docs: update .all-contributorsrc [skip ci]

* #1638 Add Parameter Object pattern

* #1638 Fix comments and formatting for Parameter Object pattern

* #1638 Fix formatting, commenting, remove string concatenation in Parameter Object pattern

* #1638 Fix readme formatting and log parameter object

.all-contributorsrc

@@ -1404,6 +1404,15 @@
       "contributions": [
         "translation"
       ]
+    },
+    {
+      "login": "richardmr36",
+      "name": "Martel Richard",
+      "avatar_url": "https://avatars.githubusercontent.com/u/19147333?v=4",
+      "profile": "https://github.com/richardmr36",
+      "contributions": [
+        "code"
+      ]
     }
   ],
   "contributorsPerLine": 4,

.github/workflows/maven-ci.yml

@@ -73,7 +73,7 @@ jobs:
     # SonarQube scan does not work for forked repositories try changing it to xvfb-run mvn clean verify
     # See https://jira.sonarsource.com/browse/MMF-1371
     - name: Build with Maven and run SonarQube analysis
-      run: xvfb-run mvn clean verify org.sonarsource.scanner.maven:sonar-maven-plugin:sonar
+      run: xvfb-run ./mvnw clean verify org.sonarsource.scanner.maven:sonar-maven-plugin:sonar
       env:
         # These two env variables are needed for sonar analysis
         GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}

.github/workflows/maven-pr-builder.yml

@@ -61,4 +61,4 @@ jobs:
     # SonarQube scan does not work for forked repositories.
     # See https://jira.sonarsource.com/browse/MMF-1371
     - name: Build with Maven
-      run: xvfb-run mvn clean verify
+      run: xvfb-run ./mvnw clean verify

.mvn/wrapper/MavenWrapperDownloader.java

@@ -0,0 +1,117 @@
+/*
+ * Copyright 2007-present the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+import java.net.*;
+import java.io.*;
+import java.nio.channels.*;
+import java.util.Properties;
+
+public class MavenWrapperDownloader {
+
+    private static final String WRAPPER_VERSION = "0.5.6";
+    /**
+     * Default URL to download the maven-wrapper.jar from, if no 'downloadUrl' is provided.
+     */
+    private static final String DEFAULT_DOWNLOAD_URL = "https://repo.maven.apache.org/maven2/io/takari/maven-wrapper/"
+        + WRAPPER_VERSION + "/maven-wrapper-" + WRAPPER_VERSION + ".jar";
+
+    /**
+     * Path to the maven-wrapper.properties file, which might contain a downloadUrl property to
+     * use instead of the default one.
+     */
+    private static final String MAVEN_WRAPPER_PROPERTIES_PATH =
+            ".mvn/wrapper/maven-wrapper.properties";
+
+    /**
+     * Path where the maven-wrapper.jar will be saved to.
+     */
+    private static final String MAVEN_WRAPPER_JAR_PATH =
+            ".mvn/wrapper/maven-wrapper.jar";
+
+    /**
+     * Name of the property which should be used to override the default download url for the wrapper.
+     */
+    private static final String PROPERTY_NAME_WRAPPER_URL = "wrapperUrl";
+
+    public static void main(String args[]) {
+        System.out.println("- Downloader started");
+        File baseDirectory = new File(args[0]);
+        System.out.println("- Using base directory: " + baseDirectory.getAbsolutePath());
+
+        // If the maven-wrapper.properties exists, read it and check if it contains a custom
+        // wrapperUrl parameter.
+        File mavenWrapperPropertyFile = new File(baseDirectory, MAVEN_WRAPPER_PROPERTIES_PATH);
+        String url = DEFAULT_DOWNLOAD_URL;
+        if(mavenWrapperPropertyFile.exists()) {
+            FileInputStream mavenWrapperPropertyFileInputStream = null;
+            try {
+                mavenWrapperPropertyFileInputStream = new FileInputStream(mavenWrapperPropertyFile);
+                Properties mavenWrapperProperties = new Properties();
+                mavenWrapperProperties.load(mavenWrapperPropertyFileInputStream);
+                url = mavenWrapperProperties.getProperty(PROPERTY_NAME_WRAPPER_URL, url);
+            } catch (IOException e) {
+                System.out.println("- ERROR loading '" + MAVEN_WRAPPER_PROPERTIES_PATH + "'");
+            } finally {
+                try {
+                    if(mavenWrapperPropertyFileInputStream != null) {
+                        mavenWrapperPropertyFileInputStream.close();
+                    }
+                } catch (IOException e) {
+                    // Ignore ...
+                }
+            }
+        }
+        System.out.println("- Downloading from: " + url);
+
+        File outputFile = new File(baseDirectory.getAbsolutePath(), MAVEN_WRAPPER_JAR_PATH);
+        if(!outputFile.getParentFile().exists()) {
+            if(!outputFile.getParentFile().mkdirs()) {
+                System.out.println(
+                        "- ERROR creating output directory '" + outputFile.getParentFile().getAbsolutePath() + "'");
+            }
+        }
+        System.out.println("- Downloading to: " + outputFile.getAbsolutePath());
+        try {
+            downloadFileFromURL(url, outputFile);
+            System.out.println("Done");
+            System.exit(0);
+        } catch (Throwable e) {
+            System.out.println("- Error downloading");
+            e.printStackTrace();
+            System.exit(1);
+        }
+    }
+
+    private static void downloadFileFromURL(String urlString, File destination) throws Exception {
+        if (System.getenv("MVNW_USERNAME") != null && System.getenv("MVNW_PASSWORD") != null) {
+            String username = System.getenv("MVNW_USERNAME");
+            char[] password = System.getenv("MVNW_PASSWORD").toCharArray();
+            Authenticator.setDefault(new Authenticator() {
+                @Override
+                protected PasswordAuthentication getPasswordAuthentication() {
+                    return new PasswordAuthentication(username, password);
+                }
+            });
+        }
+        URL website = new URL(urlString);
+        ReadableByteChannel rbc;
+        rbc = Channels.newChannel(website.openStream());
+        FileOutputStream fos = new FileOutputStream(destination);
+        fos.getChannel().transferFrom(rbc, 0, Long.MAX_VALUE);
+        fos.close();
+        rbc.close();
+    }
+
+}

.mvn/wrapper/maven-wrapper.properties

@@ -0,0 +1,25 @@
+#
+# The MIT License
+# Copyright © 2014-2021 Ilkka Seppälä
+#
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included in
+# all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+# THE SOFTWARE.
+#
+
+distributionUrl=https://repo.maven.apache.org/maven2/org/apache/maven/apache-maven/3.6.3/apache-maven-3.6.3-bin.zip
+wrapperUrl=https://repo.maven.apache.org/maven2/io/takari/maven-wrapper/0.5.6/maven-wrapper-0.5.6.jar

README.md

@@ -4,18 +4,18 @@
 
 # Design patterns implemented in Java
 
-![Java CI with Maven](https://github.com/iluwatar/java-design-patterns/workflows/Java%20CI%20with%20Maven/badge.svg)
+![Java CI](https://github.com/iluwatar/java-design-patterns/workflows/Java%20CI/badge.svg)
 [![License MIT](https://img.shields.io/badge/license-MIT-blue.svg)](https://raw.githubusercontent.com/iluwatar/java-design-patterns/master/LICENSE.md)
 [![Lines of Code](https://sonarcloud.io/api/project_badges/measure?project=iluwatar_java-design-patterns&metric=ncloc)](https://sonarcloud.io/dashboard?id=iluwatar_java-design-patterns) 
 [![Coverage](https://sonarcloud.io/api/project_badges/measure?project=iluwatar_java-design-patterns&metric=coverage)](https://sonarcloud.io/dashboard?id=iluwatar_java-design-patterns)
 [![Join the chat at https://gitter.im/iluwatar/java-design-patterns](https://badges.gitter.im/Join%20Chat.svg)](https://gitter.im/iluwatar/java-design-patterns?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge)
 <!-- ALL-CONTRIBUTORS-BADGE:START - Do not remove or modify this section -->
-[![All Contributors](https://img.shields.io/badge/all_contributors-154-orange.svg?style=flat-square)](#contributors-)
+[![All Contributors](https://img.shields.io/badge/all_contributors-155-orange.svg?style=flat-square)](#contributors-)
 <!-- ALL-CONTRIBUTORS-BADGE:END -->
 
 <br/>
 
-Read in different language : [![CN](/assets/flags/CN.png)**CN**](/zh/README.md),[![KR](/assets/flags/KR.png)**KR**](/ko/README.md),[![FR](/assets/flags/FR.png)**FR**](/fr/README.md),[![TR](/assets/flags/TR.png)**TR**](/tr/README.md),[![AR](/assets/flags/AR.png)**AR**](/ar/README.md),
+Read in different language : [![CN](/assets/flags/CN.png)**CN**](/zh/README.md), [![KR](/assets/flags/KR.png)**KR**](/ko/README.md), [![FR](/assets/flags/FR.png)**FR**](/fr/README.md), [![TR](/assets/flags/TR.png)**TR**](/tr/README.md), [![AR](/assets/flags/AR.png)**AR**](/ar/README.md)
 
 <br/>
 
@@ -306,6 +306,7 @@ This project is licensed under the terms of the MIT license.
   <tr>
     <td align="center"><a href="https://github.com/byoungju94"><img src="https://avatars.githubusercontent.com/u/42516378?v=4?s=100" width="100px;" alt=""/><br /><sub><b>byoungju94</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=byoungju94" title="Code">💻</a></td>
     <td align="center"><a href="https://github.com/moustafafarhat"><img src="https://avatars.githubusercontent.com/u/38836727?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Moustafa Farhat</b></sub></a><br /><a href="#translation-moustafafarhat" title="Translation">🌍</a></td>
+    <td align="center"><a href="https://github.com/richardmr36"><img src="https://avatars.githubusercontent.com/u/19147333?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Martel Richard</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=richardmr36" title="Code">💻</a></td>
   </tr>
 </table>
 

cloud-static-content-hosting/README.md

@@ -55,13 +55,13 @@ the content globally.
 
 4. Create IAM user that has only the necessary rights for this application.
 
-* Click `Users`
-* Click `Add user`. Choose `User name` as you wish and `Access type` should be `Programmatic access`. Click `Next: Permissions`.
-* Choose `Attach existing policies directly`. Select `AmazonS3FullAccess` and `CloudFrontFullAccess`. Click `Next: Tags`.
-* No tags are necessarily needed, so just click `Next: Review`.
-* Review the presented information and if all seems good click `Create user`.
-* You are presented with `Access key ID` and `Secret access key` which you will need to complete this example, so store them safely.
-* Click `Close`.
+   * Click `Users`
+   * Click `Add user`. Choose `User name` as you wish and `Access type` should be `Programmatic access`. Click `Next: Permissions`.
+   * Choose `Attach existing policies directly`. Select `AmazonS3FullAccess` and `CloudFrontFullAccess`. Click `Next: Tags`.
+   * No tags are necessarily needed, so just click `Next: Review`.
+   * Review the presented information and if all seems good click `Create user`.
+   * You are presented with `Access key ID` and `Secret access key` which you will need to complete this example, so store them safely.
+   * Click `Close`.
 
 5. [Install AWS Command Line Interface (AWS CLI)](https://docs.aws.amazon.com/cli/latest/userguide/install-cliv1.html) to gain programmic access to AWS cloud.
 
@@ -69,83 +69,60 @@ the content globally.
 
 7. Create AWS S3 bucket for the web site content. Note that the S3 bucket names must be globally unique.
 
-* The syntax is `aws s3 mb <bucket name>` as described in the [instructions](https://docs.aws.amazon.com/cli/latest/userguide/cli-services-s3-commands.html#using-s3-commands-managing-buckets-creating)
-* For example `aws s3 mb s3://my-static-website-jh34jsjmg`
-* Verify that the bucket was successfully created with command `aws s3 ls` which list the existing buckets
+   * The syntax is `aws s3 mb <bucket name>` as described in the [instructions](https://docs.aws.amazon.com/cli/latest/userguide/cli-services-s3-commands.html#using-s3-commands-managing-buckets-creating)
+   * For example `aws s3 mb s3://my-static-website-jh34jsjmg`
+   * Verify that the bucket was successfully created with command `aws s3 ls` which list the existing buckets
 
 8. Configure the bucket as a web site with command `aws s3 website` as described in the [instructions](https://docs.aws.amazon.com/cli/latest/reference/s3/website.html).
 
-* E.g. `aws s3 website s3://my-static-website-jh34jsjmg --index-document index.html --error-document error.html`
+   * E.g. `aws s3 website s3://my-static-website-jh34jsjmg --index-document index.html --error-document error.html`
 
 9. Upload content to the bucket.
 
-* First create the content, at least `index.html` and `error.html` documents.
-  
-index.html
-```html
-<!doctype html>
-<head>
-    <title>My Static Web Site</title>
-</head>
-<body>
-    <h1>I'm the index.html</h1>
-</body>
-```
-
-error.html
-```html
-<!doctype html>
-<head>
-    <title>My Static Web Site</title>
-</head>
-<body>
-    <h1>I'm the index.html</h1>
-</body>
-```
-
-* Upload the content to your bucket as described [here](https://docs.aws.amazon.com/cli/latest/userguide/cli-services-s3-commands.html#using-s3-commands-managing-objects-copy)
-* E.g. `aws s3 cp index.html s3://my-static-website-jh34jsjmg` and `aws s3 cp error.html s3://my-static-website-jh34jsjmg`
+   * First create the content, at least `index.html` and `error.html` documents.
+   * Upload the content to your bucket as described [here](https://docs.aws.amazon.com/cli/latest/userguide/cli-services-s3-commands.html#using-s3-commands-managing-objects-copy)
+   * E.g. `aws s3 cp index.html s3://my-static-website-jh34jsjmg` and `aws s3 cp error.html s3://my-static-website-jh34jsjmg`
 
 10. Next we need to set the bucket policy to allow read access.
 
-* Create `policy.json` with the following contents (note that you need to replace the bucket name with your own).
+    * Create `policy.json` with the following contents (note that you need to replace the bucket name with your own).
 
-```json
-{
-    "Version": "2012-10-17",
-    "Statement": [
-        {
-            "Sid": "PublicReadGetObject",
-            "Effect": "Allow",
-            "Principal": "*",
-            "Action": "s3:GetObject",
-            "Resource": "arn:aws:s3:::my-static-website-jh34jsjmg/*"
-        }
-    ]
-}
-```
+    ```json
+    {
+        "Version": "2012-10-17",
+        "Statement": [
+            {
+                "Sid": "PublicReadGetObject",
+                "Effect": "Allow",
+                "Principal": "*",
+                "Action": "s3:GetObject",
+                "Resource": "arn:aws:s3:::my-static-website-jh34jsjmg/*"
+            }
+        ]
+    }
+    ```
 
-* Set the bucket policy according to these [instructions](https://docs.aws.amazon.com/cli/latest/reference/s3api/put-bucket-policy.html)
-* E.g. `aws s3api put-bucket-policy --bucket my-static-website-jh34jsjmg --policy file://policy.json`
+    * Set the bucket policy according to these [instructions](https://docs.aws.amazon.com/cli/latest/reference/s3api/put-bucket-policy.html)
+    * E.g. `aws s3api put-bucket-policy --bucket my-static-website-jh34jsjmg --policy file://policy.json`
 
 11. Test the web site in your browser.
 
-* The web site URL format is `http://<bucket-name>.s3-website-<region-name>.amazonaws.com`
-* E.g. this web site was created in `eu-west-1` region with name `my-static-website-jh34jsjmg` so it can be accessed via url `http://my-static-website-jh34jsjmg.s3-website-eu-west-1.amazonaws.com`
+    * The web site URL format is `http://<bucket-name>.s3-website-<region-name>.amazonaws.com`
+    * E.g. this web site was created in `eu-west-1` region with name `my-static-website-jh34jsjmg` so it can be accessed via url `http://my-static-website-jh34jsjmg.s3-website-eu-west-1.amazonaws.com`
 
 12. Create CloudFormation distribution for the web site.
 
-* The syntax is described in [this reference](https://docs.aws.amazon.com/cli/latest/reference/cloudfront/create-distribution.html)
-* E.g. the easiest way is to call `aws cloudfront create-distribution --origin-domain-name my-static-website-jh34jsjmg.s3.amazonaws.com --default-root-object index.html`
-* There's also JSON syntax e.g. `--distribution-config file://dist-config.json` to pass distribution configuration arguments in file
-* The output of the call will show you the exact distribution settings including the generated CloudFront domain name you can use for testing e.g. `d2k3xwnaqa8nqx.cloudfront.net` 
-* CloudFormation distribution deployment takes some time, but once it's completed your web site is served from data centers all around the globe!
+    * The syntax is described in [this reference](https://docs.aws.amazon.com/cli/latest/reference/cloudfront/create-distribution.html)
+    * E.g. the easiest way is to call `aws cloudfront create-distribution --origin-domain-name my-static-website-jh34jsjmg.s3.amazonaws.com --default-root-object index.html`
+    * There's also JSON syntax e.g. `--distribution-config file://dist-config.json` to pass distribution configuration arguments in file
+    * The output of the call will show you the exact distribution settings including the generated CloudFront domain name you can use for testing e.g. `d2k3xwnaqa8nqx.cloudfront.net` 
+    * CloudFormation distribution deployment takes some time, but once it's completed your web site is served from data centers all around the globe!
 
 13. That's it! You have implemented a static web site with content distribution network serving it lightning fast all around the world.
 
-* To update the web site you need to update the objects in S3 bucket and invalidate the objects in the CloudFront distribution
-* To do it from AWS CLI see [this reference](https://docs.aws.amazon.com/cli/latest/reference/cloudfront/create-invalidation.html)
-* Some further development you might want to do is serve the content over https and add a domain name for your site
+    * To update the web site you need to update the objects in S3 bucket and invalidate the objects in the CloudFront distribution
+    * To do it from AWS CLI see [this reference](https://docs.aws.amazon.com/cli/latest/reference/cloudfront/create-invalidation.html)
+    * Some further development you might want to do is serve the content over https and add a domain name for your site
 
 ## Applicability
 

mvnw

@@ -0,0 +1,310 @@
+#!/bin/sh
+# ----------------------------------------------------------------------------
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+# ----------------------------------------------------------------------------
+
+# ----------------------------------------------------------------------------
+# Maven Start Up Batch script
+#
+# Required ENV vars:
+# ------------------
+#   JAVA_HOME - location of a JDK home dir
+#
+# Optional ENV vars
+# -----------------
+#   M2_HOME - location of maven2's installed home dir
+#   MAVEN_OPTS - parameters passed to the Java VM when running Maven
+#     e.g. to debug Maven itself, use
+#       set MAVEN_OPTS=-Xdebug -Xrunjdwp:transport=dt_socket,server=y,suspend=y,address=8000
+#   MAVEN_SKIP_RC - flag to disable loading of mavenrc files
+# ----------------------------------------------------------------------------
+
+if [ -z "$MAVEN_SKIP_RC" ] ; then
+
+  if [ -f /etc/mavenrc ] ; then
+    . /etc/mavenrc
+  fi
+
+  if [ -f "$HOME/.mavenrc" ] ; then
+    . "$HOME/.mavenrc"
+  fi
+
+fi
+
+# OS specific support.  $var _must_ be set to either true or false.
+cygwin=false;
+darwin=false;
+mingw=false
+case "`uname`" in
+  CYGWIN*) cygwin=true ;;
+  MINGW*) mingw=true;;
+  Darwin*) darwin=true
+    # Use /usr/libexec/java_home if available, otherwise fall back to /Library/Java/Home
+    # See https://developer.apple.com/library/mac/qa/qa1170/_index.html
+    if [ -z "$JAVA_HOME" ]; then
+      if [ -x "/usr/libexec/java_home" ]; then
+        export JAVA_HOME="`/usr/libexec/java_home`"
+      else
+        export JAVA_HOME="/Library/Java/Home"
+      fi
+    fi
+    ;;
+esac
+
+if [ -z "$JAVA_HOME" ] ; then
+  if [ -r /etc/gentoo-release ] ; then
+    JAVA_HOME=`java-config --jre-home`
+  fi
+fi
+
+if [ -z "$M2_HOME" ] ; then
+  ## resolve links - $0 may be a link to maven's home
+  PRG="$0"
+
+  # need this for relative symlinks
+  while [ -h "$PRG" ] ; do
+    ls=`ls -ld "$PRG"`
+    link=`expr "$ls" : '.*-> \(.*\)$'`
+    if expr "$link" : '/.*' > /dev/null; then
+      PRG="$link"
+    else
+      PRG="`dirname "$PRG"`/$link"
+    fi
+  done
+
+  saveddir=`pwd`
+
+  M2_HOME=`dirname "$PRG"`/..
+
+  # make it fully qualified
+  M2_HOME=`cd "$M2_HOME" && pwd`
+
+  cd "$saveddir"
+  # echo Using m2 at $M2_HOME
+fi
+
+# For Cygwin, ensure paths are in UNIX format before anything is touched
+if $cygwin ; then
+  [ -n "$M2_HOME" ] &&
+    M2_HOME=`cygpath --unix "$M2_HOME"`
+  [ -n "$JAVA_HOME" ] &&
+    JAVA_HOME=`cygpath --unix "$JAVA_HOME"`
+  [ -n "$CLASSPATH" ] &&
+    CLASSPATH=`cygpath --path --unix "$CLASSPATH"`
+fi
+
+# For Mingw, ensure paths are in UNIX format before anything is touched
+if $mingw ; then
+  [ -n "$M2_HOME" ] &&
+    M2_HOME="`(cd "$M2_HOME"; pwd)`"
+  [ -n "$JAVA_HOME" ] &&
+    JAVA_HOME="`(cd "$JAVA_HOME"; pwd)`"
+fi
+
+if [ -z "$JAVA_HOME" ]; then
+  javaExecutable="`which javac`"
+  if [ -n "$javaExecutable" ] && ! [ "`expr \"$javaExecutable\" : '\([^ ]*\)'`" = "no" ]; then
+    # readlink(1) is not available as standard on Solaris 10.
+    readLink=`which readlink`
+    if [ ! `expr "$readLink" : '\([^ ]*\)'` = "no" ]; then
+      if $darwin ; then
+        javaHome="`dirname \"$javaExecutable\"`"
+        javaExecutable="`cd \"$javaHome\" && pwd -P`/javac"
+      else
+        javaExecutable="`readlink -f \"$javaExecutable\"`"
+      fi
+      javaHome="`dirname \"$javaExecutable\"`"
+      javaHome=`expr "$javaHome" : '\(.*\)/bin'`
+      JAVA_HOME="$javaHome"
+      export JAVA_HOME
+    fi
+  fi
+fi
+
+if [ -z "$JAVACMD" ] ; then
+  if [ -n "$JAVA_HOME"  ] ; then
+    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+      # IBM's JDK on AIX uses strange locations for the executables
+      JAVACMD="$JAVA_HOME/jre/sh/java"
+    else
+      JAVACMD="$JAVA_HOME/bin/java"
+    fi
+  else
+    JAVACMD="`which java`"
+  fi
+fi
+
+if [ ! -x "$JAVACMD" ] ; then
+  echo "Error: JAVA_HOME is not defined correctly." >&2
+  echo "  We cannot execute $JAVACMD" >&2
+  exit 1
+fi
+
+if [ -z "$JAVA_HOME" ] ; then
+  echo "Warning: JAVA_HOME environment variable is not set."
+fi
+
+CLASSWORLDS_LAUNCHER=org.codehaus.plexus.classworlds.launcher.Launcher
+
+# traverses directory structure from process work directory to filesystem root
+# first directory with .mvn subdirectory is considered project base directory
+find_maven_basedir() {
+
+  if [ -z "$1" ]
+  then
+    echo "Path not specified to find_maven_basedir"
+    return 1
+  fi
+
+  basedir="$1"
+  wdir="$1"
+  while [ "$wdir" != '/' ] ; do
+    if [ -d "$wdir"/.mvn ] ; then
+      basedir=$wdir
+      break
+    fi
+    # workaround for JBEAP-8937 (on Solaris 10/Sparc)
+    if [ -d "${wdir}" ]; then
+      wdir=`cd "$wdir/.."; pwd`
+    fi
+    # end of workaround
+  done
+  echo "${basedir}"
+}
+
+# concatenates all lines of a file
+concat_lines() {
+  if [ -f "$1" ]; then
+    echo "$(tr -s '\n' ' ' < "$1")"
+  fi
+}
+
+BASE_DIR=`find_maven_basedir "$(pwd)"`
+if [ -z "$BASE_DIR" ]; then
+  exit 1;
+fi
+
+##########################################################################################
+# Extension to allow automatically downloading the maven-wrapper.jar from Maven-central
+# This allows using the maven wrapper in projects that prohibit checking in binary data.
+##########################################################################################
+if [ -r "$BASE_DIR/.mvn/wrapper/maven-wrapper.jar" ]; then
+    if [ "$MVNW_VERBOSE" = true ]; then
+      echo "Found .mvn/wrapper/maven-wrapper.jar"
+    fi
+else
+    if [ "$MVNW_VERBOSE" = true ]; then
+      echo "Couldn't find .mvn/wrapper/maven-wrapper.jar, downloading it ..."
+    fi
+    if [ -n "$MVNW_REPOURL" ]; then
+      jarUrl="$MVNW_REPOURL/io/takari/maven-wrapper/0.5.6/maven-wrapper-0.5.6.jar"
+    else
+      jarUrl="https://repo.maven.apache.org/maven2/io/takari/maven-wrapper/0.5.6/maven-wrapper-0.5.6.jar"
+    fi
+    while IFS="=" read key value; do
+      case "$key" in (wrapperUrl) jarUrl="$value"; break ;;
+      esac
+    done < "$BASE_DIR/.mvn/wrapper/maven-wrapper.properties"
+    if [ "$MVNW_VERBOSE" = true ]; then
+      echo "Downloading from: $jarUrl"
+    fi
+    wrapperJarPath="$BASE_DIR/.mvn/wrapper/maven-wrapper.jar"
+    if $cygwin; then
+      wrapperJarPath=`cygpath --path --windows "$wrapperJarPath"`
+    fi
+
+    if command -v wget > /dev/null; then
+        if [ "$MVNW_VERBOSE" = true ]; then
+          echo "Found wget ... using wget"
+        fi
+        if [ -z "$MVNW_USERNAME" ] || [ -z "$MVNW_PASSWORD" ]; then
+            wget "$jarUrl" -O "$wrapperJarPath"
+        else
+            wget --http-user=$MVNW_USERNAME --http-password=$MVNW_PASSWORD "$jarUrl" -O "$wrapperJarPath"
+        fi
+    elif command -v curl > /dev/null; then
+        if [ "$MVNW_VERBOSE" = true ]; then
+          echo "Found curl ... using curl"
+        fi
+        if [ -z "$MVNW_USERNAME" ] || [ -z "$MVNW_PASSWORD" ]; then
+            curl -o "$wrapperJarPath" "$jarUrl" -f
+        else
+            curl --user $MVNW_USERNAME:$MVNW_PASSWORD -o "$wrapperJarPath" "$jarUrl" -f
+        fi
+
+    else
+        if [ "$MVNW_VERBOSE" = true ]; then
+          echo "Falling back to using Java to download"
+        fi
+        javaClass="$BASE_DIR/.mvn/wrapper/MavenWrapperDownloader.java"
+        # For Cygwin, switch paths to Windows format before running javac
+        if $cygwin; then
+          javaClass=`cygpath --path --windows "$javaClass"`
+        fi
+        if [ -e "$javaClass" ]; then
+            if [ ! -e "$BASE_DIR/.mvn/wrapper/MavenWrapperDownloader.class" ]; then
+                if [ "$MVNW_VERBOSE" = true ]; then
+                  echo " - Compiling MavenWrapperDownloader.java ..."
+                fi
+                # Compiling the Java class
+                ("$JAVA_HOME/bin/javac" "$javaClass")
+            fi
+            if [ -e "$BASE_DIR/.mvn/wrapper/MavenWrapperDownloader.class" ]; then
+                # Running the downloader
+                if [ "$MVNW_VERBOSE" = true ]; then
+                  echo " - Running MavenWrapperDownloader.java ..."
+                fi
+                ("$JAVA_HOME/bin/java" -cp .mvn/wrapper MavenWrapperDownloader "$MAVEN_PROJECTBASEDIR")
+            fi
+        fi
+    fi
+fi
+##########################################################################################
+# End of extension
+##########################################################################################
+
+export MAVEN_PROJECTBASEDIR=${MAVEN_BASEDIR:-"$BASE_DIR"}
+if [ "$MVNW_VERBOSE" = true ]; then
+  echo $MAVEN_PROJECTBASEDIR
+fi
+MAVEN_OPTS="$(concat_lines "$MAVEN_PROJECTBASEDIR/.mvn/jvm.config") $MAVEN_OPTS"
+
+# For Cygwin, switch paths to Windows format before running java
+if $cygwin; then
+  [ -n "$M2_HOME" ] &&
+    M2_HOME=`cygpath --path --windows "$M2_HOME"`
+  [ -n "$JAVA_HOME" ] &&
+    JAVA_HOME=`cygpath --path --windows "$JAVA_HOME"`
+  [ -n "$CLASSPATH" ] &&
+    CLASSPATH=`cygpath --path --windows "$CLASSPATH"`
+  [ -n "$MAVEN_PROJECTBASEDIR" ] &&
+    MAVEN_PROJECTBASEDIR=`cygpath --path --windows "$MAVEN_PROJECTBASEDIR"`
+fi
+
+# Provide a "standardized" way to retrieve the CLI args that will
+# work with both Windows and non-Windows executions.
+MAVEN_CMD_LINE_ARGS="$MAVEN_CONFIG $@"
+export MAVEN_CMD_LINE_ARGS
+
+WRAPPER_LAUNCHER=org.apache.maven.wrapper.MavenWrapperMain
+
+exec "$JAVACMD" \
+  $MAVEN_OPTS \
+  -classpath "$MAVEN_PROJECTBASEDIR/.mvn/wrapper/maven-wrapper.jar" \
+  "-Dmaven.home=${M2_HOME}" "-Dmaven.multiModuleProjectDirectory=${MAVEN_PROJECTBASEDIR}" \
+  ${WRAPPER_LAUNCHER} $MAVEN_CONFIG "$@"

mvnw.cmd

@@ -0,0 +1,182 @@
+@REM ----------------------------------------------------------------------------
+@REM Licensed to the Apache Software Foundation (ASF) under one
+@REM or more contributor license agreements.  See the NOTICE file
+@REM distributed with this work for additional information
+@REM regarding copyright ownership.  The ASF licenses this file
+@REM to you under the Apache License, Version 2.0 (the
+@REM "License"); you may not use this file except in compliance
+@REM with the License.  You may obtain a copy of the License at
+@REM
+@REM    http://www.apache.org/licenses/LICENSE-2.0
+@REM
+@REM Unless required by applicable law or agreed to in writing,
+@REM software distributed under the License is distributed on an
+@REM "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+@REM KIND, either express or implied.  See the License for the
+@REM specific language governing permissions and limitations
+@REM under the License.
+@REM ----------------------------------------------------------------------------
+
+@REM ----------------------------------------------------------------------------
+@REM Maven Start Up Batch script
+@REM
+@REM Required ENV vars:
+@REM JAVA_HOME - location of a JDK home dir
+@REM
+@REM Optional ENV vars
+@REM M2_HOME - location of maven2's installed home dir
+@REM MAVEN_BATCH_ECHO - set to 'on' to enable the echoing of the batch commands
+@REM MAVEN_BATCH_PAUSE - set to 'on' to wait for a keystroke before ending
+@REM MAVEN_OPTS - parameters passed to the Java VM when running Maven
+@REM     e.g. to debug Maven itself, use
+@REM set MAVEN_OPTS=-Xdebug -Xrunjdwp:transport=dt_socket,server=y,suspend=y,address=8000
+@REM MAVEN_SKIP_RC - flag to disable loading of mavenrc files
+@REM ----------------------------------------------------------------------------
+
+@REM Begin all REM lines with '@' in case MAVEN_BATCH_ECHO is 'on'
+@echo off
+@REM set title of command window
+title %0
+@REM enable echoing by setting MAVEN_BATCH_ECHO to 'on'
+@if "%MAVEN_BATCH_ECHO%" == "on"  echo %MAVEN_BATCH_ECHO%
+
+@REM set %HOME% to equivalent of $HOME
+if "%HOME%" == "" (set "HOME=%HOMEDRIVE%%HOMEPATH%")
+
+@REM Execute a user defined script before this one
+if not "%MAVEN_SKIP_RC%" == "" goto skipRcPre
+@REM check for pre script, once with legacy .bat ending and once with .cmd ending
+if exist "%HOME%\mavenrc_pre.bat" call "%HOME%\mavenrc_pre.bat"
+if exist "%HOME%\mavenrc_pre.cmd" call "%HOME%\mavenrc_pre.cmd"
+:skipRcPre
+
+@setlocal
+
+set ERROR_CODE=0
+
+@REM To isolate internal variables from possible post scripts, we use another setlocal
+@setlocal
+
+@REM ==== START VALIDATION ====
+if not "%JAVA_HOME%" == "" goto OkJHome
+
+echo.
+echo Error: JAVA_HOME not found in your environment. >&2
+echo Please set the JAVA_HOME variable in your environment to match the >&2
+echo location of your Java installation. >&2
+echo.
+goto error
+
+:OkJHome
+if exist "%JAVA_HOME%\bin\java.exe" goto init
+
+echo.
+echo Error: JAVA_HOME is set to an invalid directory. >&2
+echo JAVA_HOME = "%JAVA_HOME%" >&2
+echo Please set the JAVA_HOME variable in your environment to match the >&2
+echo location of your Java installation. >&2
+echo.
+goto error
+
+@REM ==== END VALIDATION ====
+
+:init
+
+@REM Find the project base dir, i.e. the directory that contains the folder ".mvn".
+@REM Fallback to current working directory if not found.
+
+set MAVEN_PROJECTBASEDIR=%MAVEN_BASEDIR%
+IF NOT "%MAVEN_PROJECTBASEDIR%"=="" goto endDetectBaseDir
+
+set EXEC_DIR=%CD%
+set WDIR=%EXEC_DIR%
+:findBaseDir
+IF EXIST "%WDIR%"\.mvn goto baseDirFound
+cd ..
+IF "%WDIR%"=="%CD%" goto baseDirNotFound
+set WDIR=%CD%
+goto findBaseDir
+
+:baseDirFound
+set MAVEN_PROJECTBASEDIR=%WDIR%
+cd "%EXEC_DIR%"
+goto endDetectBaseDir
+
+:baseDirNotFound
+set MAVEN_PROJECTBASEDIR=%EXEC_DIR%
+cd "%EXEC_DIR%"
+
+:endDetectBaseDir
+
+IF NOT EXIST "%MAVEN_PROJECTBASEDIR%\.mvn\jvm.config" goto endReadAdditionalConfig
+
+@setlocal EnableExtensions EnableDelayedExpansion
+for /F "usebackq delims=" %%a in ("%MAVEN_PROJECTBASEDIR%\.mvn\jvm.config") do set JVM_CONFIG_MAVEN_PROPS=!JVM_CONFIG_MAVEN_PROPS! %%a
+@endlocal & set JVM_CONFIG_MAVEN_PROPS=%JVM_CONFIG_MAVEN_PROPS%
+
+:endReadAdditionalConfig
+
+SET MAVEN_JAVA_EXE="%JAVA_HOME%\bin\java.exe"
+set WRAPPER_JAR="%MAVEN_PROJECTBASEDIR%\.mvn\wrapper\maven-wrapper.jar"
+set WRAPPER_LAUNCHER=org.apache.maven.wrapper.MavenWrapperMain
+
+set DOWNLOAD_URL="https://repo.maven.apache.org/maven2/io/takari/maven-wrapper/0.5.6/maven-wrapper-0.5.6.jar"
+
+FOR /F "tokens=1,2 delims==" %%A IN ("%MAVEN_PROJECTBASEDIR%\.mvn\wrapper\maven-wrapper.properties") DO (
+    IF "%%A"=="wrapperUrl" SET DOWNLOAD_URL=%%B
+)
+
+@REM Extension to allow automatically downloading the maven-wrapper.jar from Maven-central
+@REM This allows using the maven wrapper in projects that prohibit checking in binary data.
+if exist %WRAPPER_JAR% (
+    if "%MVNW_VERBOSE%" == "true" (
+        echo Found %WRAPPER_JAR%
+    )
+) else (
+    if not "%MVNW_REPOURL%" == "" (
+        SET DOWNLOAD_URL="%MVNW_REPOURL%/io/takari/maven-wrapper/0.5.6/maven-wrapper-0.5.6.jar"
+    )
+    if "%MVNW_VERBOSE%" == "true" (
+        echo Couldn't find %WRAPPER_JAR%, downloading it ...
+        echo Downloading from: %DOWNLOAD_URL%
+    )
+
+    powershell -Command "&{"^
+		"$webclient = new-object System.Net.WebClient;"^
+		"if (-not ([string]::IsNullOrEmpty('%MVNW_USERNAME%') -and [string]::IsNullOrEmpty('%MVNW_PASSWORD%'))) {"^
+		"$webclient.Credentials = new-object System.Net.NetworkCredential('%MVNW_USERNAME%', '%MVNW_PASSWORD%');"^
+		"}"^
+		"[Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]::Tls12; $webclient.DownloadFile('%DOWNLOAD_URL%', '%WRAPPER_JAR%')"^
+		"}"
+    if "%MVNW_VERBOSE%" == "true" (
+        echo Finished downloading %WRAPPER_JAR%
+    )
+)
+@REM End of extension
+
+@REM Provide a "standardized" way to retrieve the CLI args that will
+@REM work with both Windows and non-Windows executions.
+set MAVEN_CMD_LINE_ARGS=%*
+
+%MAVEN_JAVA_EXE% %JVM_CONFIG_MAVEN_PROPS% %MAVEN_OPTS% %MAVEN_DEBUG_OPTS% -classpath %WRAPPER_JAR% "-Dmaven.multiModuleProjectDirectory=%MAVEN_PROJECTBASEDIR%" %WRAPPER_LAUNCHER% %MAVEN_CONFIG% %*
+if ERRORLEVEL 1 goto error
+goto end
+
+:error
+set ERROR_CODE=1
+
+:end
+@endlocal & set ERROR_CODE=%ERROR_CODE%
+
+if not "%MAVEN_SKIP_RC%" == "" goto skipRcPost
+@REM check for post script, once with legacy .bat ending and once with .cmd ending
+if exist "%HOME%\mavenrc_post.bat" call "%HOME%\mavenrc_post.bat"
+if exist "%HOME%\mavenrc_post.cmd" call "%HOME%\mavenrc_post.cmd"
+:skipRcPost
+
+@REM pause the script if MAVEN_BATCH_PAUSE is set to 'on'
+if "%MAVEN_BATCH_PAUSE%" == "on" pause
+
+if "%MAVEN_TERMINATE_CMD%" == "on" exit %ERROR_CODE%
+
+exit /B %ERROR_CODE%

parameter-object/README.md

@@ -0,0 +1,138 @@
+---
+layout: pattern
+title: Parameter Object
+folder: parameter-object
+permalink: /patterns/parameter-object/
+categories: Behavioral
+tags:
+ - Extensibility
+---
+
+## Intent
+
+The syntax of Java language doesn’t allow you to declare a method with a predefined value
+for a parameter. Probably the best option to achieve default method parameters in Java is
+by using the method overloading. Method overloading allows you to declare several methods
+with the same name but with a different number of parameters. But the main problem with
+method overloading as a solution for default parameter values reveals itself when a method
+accepts multiple parameters. Creating an overloaded method for each possible combination of
+parameters might be cumbersome. To deal with this issue, the Parameter Object pattern is used.
+
+## Explanation
+
+The Parameter Object is simply a wrapper object for all parameters of a method.
+It is nothing more than just a regular POJO. The advantage of the Parameter Object over a
+regular method parameter list is the fact that class fields can have default values.
+Once the wrapper class is created for the method parameter list, a corresponding builder class
+is also created. Usually it's an inner static class. The final step is to use the builder
+to construct a new parameter object. For those parameters that are skipped,
+their default values are going to be used.
+
+
+**Programmatic Example**
+
+Here's the simple `SearchService` class where Method Overloading is used to default values here. To use method overloading, either the number of arguments or argument type has to be different.
+
+```java
+public class SearchService {
+  //Method Overloading example. SortOrder is defaulted in this method
+  public String search(String type, String sortBy) {
+    return getQuerySummary(type, sortBy, SortOrder.DESC);
+  }
+
+  /* Method Overloading example. SortBy is defaulted in this method. Note that the type has to be 
+  different here to overload the method */
+  public String search(String type, SortOrder sortOrder) {
+    return getQuerySummary(type, "price", sortOrder);
+  }
+
+  private String getQuerySummary(String type, String sortBy, SortOrder sortOrder) {
+    return "Requesting shoes of type \"" + type + "\" sorted by \"" + sortBy + "\" in \""
+        + sortOrder.getValue() + "ending\" order...";
+  }
+}
+
+```
+
+Next we present the `SearchService` with `ParameterObject` created with Builder pattern.
+
+```java
+public class SearchService {
+
+  /* Parameter Object example. Default values are abstracted into the Parameter Object 
+  at the time of Object creation */
+  public String search(ParameterObject parameterObject) {
+    return getQuerySummary(parameterObject.getType(), parameterObject.getSortBy(),
+        parameterObject.getSortOrder());
+  }
+  
+  private String getQuerySummary(String type, String sortBy, SortOrder sortOrder) {
+    return "Requesting shoes of type \"" + type + "\" sorted by \"" + sortBy + "\" in \""
+        + sortOrder.getValue() + "ending\" order...";
+  }
+}
+
+public class ParameterObject {
+  public static final String DEFAULT_SORT_BY = "price";
+  public static final SortOrder DEFAULT_SORT_ORDER = SortOrder.ASC;
+
+  private String type;
+  private String sortBy = DEFAULT_SORT_BY;
+  private SortOrder sortOrder = DEFAULT_SORT_ORDER;
+
+  private ParameterObject(Builder builder) {
+    type = builder.type;
+    sortBy = builder.sortBy != null && !builder.sortBy.isBlank() ? builder.sortBy : sortBy;
+    sortOrder = builder.sortOrder != null ? builder.sortOrder : sortOrder;
+  }
+
+  public static Builder newBuilder() {
+    return new Builder();
+  }
+
+  //Getters and Setters...
+
+  public static final class Builder {
+
+    private String type;
+    private String sortBy;
+    private SortOrder sortOrder;
+
+    private Builder() {
+    }
+
+    public Builder withType(String type) {
+      this.type = type;
+      return this;
+    }
+
+    public Builder sortBy(String sortBy) {
+      this.sortBy = sortBy;
+      return this;
+    }
+
+    public Builder sortOrder(SortOrder sortOrder) {
+      this.sortOrder = sortOrder;
+      return this;
+    }
+
+    public ParameterObject build() {
+      return new ParameterObject(this);
+    }
+  }
+}
+
+
+```
+
+## Class diagram
+
+![alt text](./etc/parameter-object.png "Parameter Object")
+
+## Applicability
+
+This pattern shows us the way to have default parameters for a method in Java as the language doesn't default parameters feature out of the box. 
+
+## Credits
+
+- [Does Java have default parameters?](http://dolszewski.com/java/java-default-parameters)

parameter-object/etc/parameter-object.urm.puml

@@ -0,0 +1,52 @@
+@startuml
+package com.iluwatar.parameter.object {
+  class App {
+    - LOGGER : Logger {static}
+    + App()
+    + main(args : String[]) {static}
+  }
+  class ParameterObject {
+    + DEFAULT_SORT_BY : String {static}
+    + DEFAULT_SORT_ORDER : SortOrder {static}
+    - sortBy : String
+    - sortOrder : SortOrder
+    - type : String
+    - ParameterObject(builder : Builder)
+    + getSortBy() : String
+    + getSortOrder() : SortOrder
+    + getType() : String
+    + newBuilder() : Builder {static}
+    + setSortBy(sortBy : String)
+    + setSortOrder(sortOrder : SortOrder)
+    + setType(type : String)
+  }
+  class Builder {
+    - sortBy : String
+    - sortOrder : SortOrder
+    - type : String
+    - Builder()
+    + build() : ParameterObject
+    + sortBy(sortBy : String) : Builder
+    + sortOrder(sortOrder : SortOrder) : Builder
+    + withType(type : String) : Builder
+  }
+  class SearchService {
+    + SearchService()
+    - getQuerySummary(type : String, sortBy : String, sortOrder : SortOrder) : String
+    + search(parameterObject : ParameterObject) : String
+    + search(type : String, sortBy : String) : String
+    + search(type : String, sortOrder : SortOrder) : String
+  }
+  enum SortOrder {
+    + ASC {static}
+    + DESC {static}
+    - value : String
+    + getValue() : String
+    + valueOf(name : String) : SortOrder {static}
+    + values() : SortOrder[] {static}
+  }
+}
+Builder -->  "-sortOrder" SortOrder
+Builder ..+ ParameterObject
+ParameterObject -->  "-DEFAULT_SORT_ORDER" SortOrder
+@enduml

parameter-object/pom.xml

@@ -0,0 +1,61 @@
+<?xml version="1.0"?>
+<!--
+
+    The MIT License
+    Copyright © 2014-2019 Ilkka Seppälä
+
+    Permission is hereby granted, free of charge, to any person obtaining a copy
+    of this software and associated documentation files (the "Software"), to deal
+    in the Software without restriction, including without limitation the rights
+    to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+    copies of the Software, and to permit persons to whom the Software is
+    furnished to do so, subject to the following conditions:
+
+    The above copyright notice and this permission notice shall be included in
+    all copies or substantial portions of the Software.
+
+    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+    AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+    OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+    THE SOFTWARE.
+
+-->
+<project xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd" xmlns="http://maven.apache.org/POM/4.0.0"
+    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
+  <modelVersion>4.0.0</modelVersion>
+  <parent>
+    <groupId>com.iluwatar</groupId>
+    <artifactId>java-design-patterns</artifactId>
+    <version>1.24.0-SNAPSHOT</version>
+  </parent>
+  <artifactId>parameter-object</artifactId>
+  <dependencies>
+    <dependency>
+      <groupId>org.junit.jupiter</groupId>
+      <artifactId>junit-jupiter-engine</artifactId>
+      <scope>test</scope>
+    </dependency>
+  </dependencies>
+  <build>
+    <plugins>
+      <plugin>
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-assembly-plugin</artifactId>
+        <executions>
+          <execution>
+            <configuration>
+              <archive>
+                <manifest>
+                  <mainClass>com.iluwatar.parameter.object.App</mainClass>
+                </manifest>
+              </archive>
+            </configuration>
+          </execution>
+        </executions>
+      </plugin>
+    </plugins>
+  </build>
+</project>

parameter-object/src/main/java/com/iluwatar/parameter/object/App.java

@@ -0,0 +1,62 @@
+/*
+ * The MIT License
+ * Copyright © 2014-2019 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+package com.iluwatar.parameter.object;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * The syntax of Java language doesn’t allow you to declare a method with a predefined value
+ * for a parameter. Probably the best option to achieve default method parameters in Java is
+ * by using the method overloading. Method overloading allows you to declare several methods
+ * with the same name but with a different number of parameters. But the main problem with
+ * method overloading as a solution for default parameter values reveals itself when a method
+ * accepts multiple parameters. Creating an overloaded method for each possible combination of
+ * parameters might be cumbersome. To deal with this issue, the Parameter Object pattern is used.
+ * The Parameter Object is simply a wrapper object for all parameters of a method.
+ * It is nothing more than just a regular POJO. The advantage of the Parameter Object over a
+ * regular method parameter list is the fact that class fields can have default values.
+ * Once the wrapper class is created for the method parameter list, a corresponding builder class
+ * is also created. Usually it's an inner static class. The final step is to use the builder
+ * to construct a new parameter object. For those parameters that are skipped,
+ * their default values are going to be used.
+ */
+public class App {
+
+  private static final Logger LOGGER = LoggerFactory.getLogger(App.class);
+
+  /**
+   * Program entry point.
+   *
+   * @param args command line args
+   */
+  public static void main(String[] args) {
+    ParameterObject params = ParameterObject.newBuilder()
+        .withType("sneakers")
+        .sortBy("brand")
+        .build();
+    LOGGER.info(params.toString());
+    LOGGER.info(new SearchService().search(params));
+  }
+}

parameter-object/src/main/java/com/iluwatar/parameter/object/ParameterObject.java

@@ -0,0 +1,113 @@
+/*
+ * The MIT License
+ * Copyright © 2014-2019 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+package com.iluwatar.parameter.object;
+
+public class ParameterObject {
+
+  /**
+   * Default values are defined here.
+   */
+  public static final String DEFAULT_SORT_BY = "price";
+  public static final SortOrder DEFAULT_SORT_ORDER = SortOrder.ASC;
+
+  private String type;
+
+  /**
+   * Default values are assigned here.
+   */
+  private String sortBy = DEFAULT_SORT_BY;
+  private SortOrder sortOrder = DEFAULT_SORT_ORDER;
+
+  /**
+   * Overriding default values on object creation only when builder object has a valid value.
+   */
+  private ParameterObject(Builder builder) {
+    setType(builder.type);
+    setSortBy(builder.sortBy != null && !builder.sortBy.isBlank() ? builder.sortBy : sortBy);
+    setSortOrder(builder.sortOrder != null ? builder.sortOrder : sortOrder);
+  }
+
+  public static Builder newBuilder() {
+    return new Builder();
+  }
+
+  public String getType() {
+    return type;
+  }
+
+  public void setType(String type) {
+    this.type = type;
+  }
+
+  public String getSortBy() {
+    return sortBy;
+  }
+
+  public void setSortBy(String sortBy) {
+    this.sortBy = sortBy;
+  }
+
+  public SortOrder getSortOrder() {
+    return sortOrder;
+  }
+
+  public void setSortOrder(SortOrder sortOrder) {
+    this.sortOrder = sortOrder;
+  }
+
+  @Override
+  public String toString() {
+    return String.format("ParameterObject[type='%s', sortBy='%s', sortOrder='%s']",
+        type, sortBy, sortOrder);
+  }
+
+  public static final class Builder {
+
+    private String type;
+    private String sortBy;
+    private SortOrder sortOrder;
+
+    private Builder() {
+    }
+
+    public Builder withType(String type) {
+      this.type = type;
+      return this;
+    }
+
+    public Builder sortBy(String sortBy) {
+      this.sortBy = sortBy;
+      return this;
+    }
+
+    public Builder sortOrder(SortOrder sortOrder) {
+      this.sortOrder = sortOrder;
+      return this;
+    }
+
+    public ParameterObject build() {
+      return new ParameterObject(this);
+    }
+  }
+}

parameter-object/src/main/java/com/iluwatar/parameter/object/SearchService.java

@@ -0,0 +1,60 @@
+/*
+ * The MIT License
+ * Copyright © 2014-2019 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+package com.iluwatar.parameter.object;
+
+public class SearchService {
+
+  /**
+   * Below two methods of name `search` is overloaded so that we can send a default value for
+   * one of the criteria and call the final api. A default SortOrder is sent in the first method
+   * and a default SortBy is sent in the second method. So two separate method definitions are
+   * needed for having default values for one argument in each case. Hence multiple overloaded
+   * methods are needed as the number of argument increases.
+   */
+  public String search(String type, String sortBy) {
+    return getQuerySummary(type, sortBy, SortOrder.ASC);
+  }
+
+  public String search(String type, SortOrder sortOrder) {
+    return getQuerySummary(type, "price", sortOrder);
+  }
+
+
+  /**
+   * The need for multiple method definitions can be avoided by the Parameter Object pattern.
+   * Below is the example where only one method is required and all the logic for having default
+   * values are abstracted into the Parameter Object at the time of object creation.
+   */
+  public String search(ParameterObject parameterObject) {
+    return getQuerySummary(parameterObject.getType(), parameterObject.getSortBy(),
+        parameterObject.getSortOrder());
+  }
+
+  private String getQuerySummary(String type, String sortBy, SortOrder sortOrder) {
+    return String.format("Requesting shoes of type \"%s\" sorted by \"%s\" in \"%sending\" order..",
+        type,
+        sortBy,
+        sortOrder.getValue());
+  }
+}

parameter-object/src/main/java/com/iluwatar/parameter/object/SortOrder.java

@@ -0,0 +1,39 @@
+/*
+ * The MIT License
+ * Copyright © 2014-2019 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+package com.iluwatar.parameter.object;
+
+public enum SortOrder {
+  ASC("asc"),
+  DESC("desc");
+
+  private String value;
+
+  SortOrder(String value) {
+    this.value = value;
+  }
+
+  public String getValue() {
+    return value;
+  }
+}

parameter-object/src/test/java/com/iluwatar/parameter/object/AppTest.java

@@ -0,0 +1,41 @@
+/*
+ * The MIT License
+ * Copyright © 2014-2019 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+package com.iluwatar.parameter.object;
+
+import org.junit.jupiter.api.Test;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * Application test
+ */
+class AppTest {
+  private static final Logger LOGGER = LoggerFactory.getLogger(AppTest.class);
+
+  @Test
+  void shouldExecuteApplicationWithoutException() {
+    App.main(new String[]{});
+    LOGGER.info("Executed successfully without exception.");
+  }
+}

parameter-object/src/test/java/com/iluwatar/parameter/object/ParameterObjectTest.java

@@ -0,0 +1,63 @@
+/*
+ * The MIT License
+ * Copyright © 2014-2019 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+package com.iluwatar.parameter.object;
+
+import org.junit.jupiter.api.Test;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+class ParameterObjectTest {
+
+  private static final Logger LOGGER = LoggerFactory.getLogger(ParameterObjectTest.class);
+
+  @Test
+  public void testForDefaultSortBy() {
+    //Creating parameter object with default value for SortBy set
+    ParameterObject params = ParameterObject.newBuilder()
+        .withType("sneakers")
+        .sortOrder(SortOrder.DESC)
+        .build();
+
+    assertEquals(ParameterObject.DEFAULT_SORT_BY, params.getSortBy(),
+        "Default SortBy is not set.");
+    LOGGER.info("{} Default parameter value is set during object creation as no value is passed."
+        , "SortBy");
+  }
+
+  @Test
+  public void testForDefaultSortOrder() {
+    //Creating parameter object with default value for SortOrder set
+    ParameterObject params = ParameterObject.newBuilder()
+        .withType("sneakers")
+        .sortBy("brand")
+        .build();
+
+    assertEquals(ParameterObject.DEFAULT_SORT_ORDER, params.getSortOrder(),
+        "Default SortOrder is not set.");
+    LOGGER.info("{} Default parameter value is set during object creation as no value is passed."
+        , "SortOrder");
+  }
+}

parameter-object/src/test/java/com/iluwatar/parameter/object/SearchServiceTest.java

@@ -0,0 +1,63 @@
+/*
+ * The MIT License
+ * Copyright © 2014-2019 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+package com.iluwatar.parameter.object;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+class SearchServiceTest {
+  private static final Logger LOGGER = LoggerFactory.getLogger(SearchServiceTest.class);
+  private ParameterObject parameterObject;
+  private SearchService searchService;
+
+  @BeforeEach
+  public void setUp() {
+    //Creating parameter object with default values set
+    parameterObject = ParameterObject.newBuilder()
+        .withType("sneakers")
+        .build();
+
+    searchService = new SearchService();
+  }
+
+  /**
+   *  Testing parameter object against the overloaded method to verify if the behaviour is same.
+   */
+  @Test
+  public void testDefaultParametersMatch() {
+    assertEquals(searchService.search(parameterObject), searchService.search("sneakers",
+        SortOrder.ASC), "Default Parameter values do not not match.");
+    LOGGER.info("SortBy Default parameter value matches.");
+
+    assertEquals(searchService.search(parameterObject), searchService.search("sneakers",
+        "price"), "Default Parameter values do not not match.");
+    LOGGER.info("SortOrder Default parameter value matches.");
+
+    LOGGER.info("testDefaultParametersMatch executed successfully without errors.");
+  }
+}

pom.xml

@@ -45,7 +45,7 @@
         <junit-vintage.version>${junit.version}.2</junit-vintage.version>
         <sping-test-junit5.version>1.0.2</sping-test-junit5.version>
         <compiler.version>3.8.1</compiler.version>
-        <jacoco.version>0.8.4</jacoco.version>
+        <jacoco.version>0.8.6</jacoco.version>
         <commons-dbcp.version>1.4</commons-dbcp.version>
         <camel.version>2.24.0</camel.version>
         <guava.version>19.0</guava.version>
@@ -208,6 +208,7 @@
         <module>factory</module>
         <module>separated-interface</module>
         <module>special-case</module>
+        <module>parameter-object</module>
     </modules>
 
     <repositories>