Merge pull request #42 from joshzambales/master

Updated pull request

README.md

@@ -1,4 +1,3 @@
-
 # Design pattern samples in Java.
 
 ## Build status:
@@ -62,6 +61,13 @@ Behavioral patterns are concerned with algorithms and the assignment of responsi
 * [Callback](#callback)
 * [Execute Around](#execute-around)
 
+### Presentation Tier Patterns
+
+Presentation Tier patterns are the top-most level of the application, this is concerned with translating tasks and results to something the user can understand.
+
+* [Intercepting Filter](#intercepting-filter)
+
+
 ## <a name="abstract-factory">Abstract Factory</a> [&#8593;](#list-of-design-patterns)
 **Intent:** Provide an interface for creating families of related or dependent objects without specifying their concrete classes.
 
@@ -431,6 +437,17 @@ Behavioral patterns are concerned with algorithms and the assignment of responsi
 **Applicability:** Use the Callback pattern when
 * When some arbitrary synchronous or asynchronous action must be performed after execution of some defined activity.
 
+
+## <a name="intercepting-filter">Intercepting Filter</a> [&#8593;](#list-of-design-patterns)
+**Intent:** Provide pluggable filters to conduct necessary pre-processing and post-processing to requests from a client to a target
+ 
+![alt text](https://github.com/iluwatar/java-design-patterns/blob/master/intercepting-filter/etc/Intercepting-filter.png "Intercepting Filter")
+ 
+**Applicability:** Use the Intercepting Filter pattern when
+* a system uses pre-processing or post-processing requests
+* a system should do the authentication/ authorization/ logging or tracking of request and then pass the requests to corresponding handlers 
+* you want a modular approach to configuring pre-processing and post-processing schemes
+
 **Real world examples:**
 * [CyclicBarrier] (http://docs.oracle.com/javase/7/docs/api/java/util/concurrent/CyclicBarrier.html#CyclicBarrier%28int,%20java.lang.Runnable%29) constructor can accept callback that will be triggered every time when barrier is tripped.
 
@@ -453,6 +470,7 @@ Behavioral patterns are concerned with algorithms and the assignment of responsi
 **Real world examples:**
 * [JavaScript](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Inheritance_and_the_prototype_chain) prototype inheritance
 
+
 # Frequently asked questions
 
 **<a id="Q1">Q: What is the difference between State and Strategy patterns?</a>**
@@ -497,10 +515,13 @@ The difference is the intent of the patterns. While Proxy controls access to the
 * [Let’s Modify the Objects-First Approach into Design-Patterns-First](http://edu.pecinovsky.cz/papers/2006_ITiCSE_Design_Patterns_First.pdf)
 * [Pattern Languages of Program Design](http://www.amazon.com/Pattern-Languages-Program-Design-Coplien/dp/0201607344/ref=sr_1_1)
 * [Martin Fowler - Event Aggregator](http://martinfowler.com/eaaDev/EventAggregator.html)
+* [TutorialsPoint - Intercepting Filter](http://www.tutorialspoint.com/design_pattern/intercepting_filter_pattern.htm)
+* [Presentation Tier Pattern](http://www.javagyan.com/tutorials/corej2eepatterns/presentation-tier-patterns)
 * [Functional Programming in Java: Harnessing the Power of Java 8 Lambda Expressions](http://www.amazon.com/Functional-Programming-Java-Harnessing-Expressions/dp/1937785467/ref=sr_1_1)
 
 
 
+
 # License
 
 This project is licensed under the terms of the MIT license.

intercepting-filter/pom.xml

@@ -0,0 +1,18 @@
+<?xml version="1.0"?>
+<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>1.0-SNAPSHOT</version>
+  </parent>
+  <artifactId>intercepting-filter</artifactId>
+  <dependencies>
+    <dependency>
+      <groupId>junit</groupId>
+      <artifactId>junit</artifactId>
+      <scope>test</scope>
+    </dependency>
+  </dependencies>
+</project>

intercepting-filter/src/main/java/com/iluwatar/AddressFilter.java

@@ -0,0 +1,14 @@
+package com.iluwatar;
+/**
+ * Concrete implementation of filter
+ * This filter is responsible for checking/filtering the input in the address field, returns null if field is empty
+ * @author joshzambales
+ *
+ */
+public class AddressFilter implements Filter{
+	public String execute(String[] request){
+		if(request[2].equals("")){
+			return null;
+		}else return request[2];
+	}
+}

intercepting-filter/src/main/java/com/iluwatar/App.java

@@ -0,0 +1,35 @@
+package com.iluwatar;
+import java.util.*;
+import javax.swing.*;
+import javax.swing.table.*;
+import java.awt.*;
+import java.awt.event.*;
+/**
+ *
+ * This is an app that checks whether the order request is valid through pre-processing done via Filters
+ * Each field has its own corresponding Filter
+ * @author joshzambales
+ *
+ */
+public class App{
+	public static void main(String[] args){
+		FilterManager filterManager = new FilterManager(new Target());
+		filterManager.setFilter(new NameFilter());
+		filterManager.setFilter(new ContactFilter());
+		filterManager.setFilter(new AddressFilter());
+		filterManager.setFilter(new DepositFilter());
+		filterManager.setFilter(new OrderFilter());
+
+		Client client = new Client();
+		client.setFilterManager(filterManager);
+	}
+}
+
+
+
+
+
+
+
+
+

intercepting-filter/src/main/java/com/iluwatar/Client.java

@@ -0,0 +1,90 @@
+package com.iluwatar;
+ import java.util.*;
+import javax.swing.*;
+import javax.swing.table.*;
+import java.awt.*;
+import java.awt.event.*;
+
+/**
+ * The Client class is responsible for handling the input and running them through filters inside the filterManager
+ *
+ * This is where Filters come to play as the client pre-processes the request before being displayed in the Target
+ * 
+ * @author joshzambales
+ *
+ */
+public class Client extends JFrame{
+	private FilterManager filterManager;
+	private JLabel jl;
+	private JTextField[] jtFields;
+	private JTextArea[] jtAreas;
+	private JButton clearButton, processButton;
+	public Client(){
+		super("Client System");
+		setDefaultCloseOperation(EXIT_ON_CLOSE);
+		setSize(300,300);
+		jl = new JLabel("RUNNING...");
+		jtFields = new JTextField[3];
+		for(int i = 0; i < 3; i++){
+			jtFields[i] = new JTextField();
+		}
+		jtAreas = new JTextArea[2];
+		for(int i = 0; i < 2; i++){
+			jtAreas[i] = new JTextArea();
+		}
+		 clearButton = new JButton("Clear");
+		 processButton = new JButton("Process");
+
+		setup();
+	}
+	private void setup(){
+		setLayout(new BorderLayout());
+		JPanel panel = new JPanel();
+		add(jl,BorderLayout.SOUTH);
+		add(panel, BorderLayout.CENTER);
+		panel.setLayout(new GridLayout(6,2));
+		panel.add(new JLabel("Name"));
+		panel.add(jtFields[0]);
+		panel.add(new JLabel("Contact Number"));
+		panel.add(jtFields[1]);
+		panel.add(new JLabel("Address"));
+		panel.add(jtAreas[0]);
+		panel.add(new JLabel("Deposit Number"));
+		panel.add(jtFields[2]);
+		panel.add(new JLabel("Order"));
+		panel.add(jtAreas[1]);
+		panel.add(clearButton);
+		panel.add(processButton);
+
+		clearButton.addActionListener(new ActionListener(){
+			@Override
+			public void actionPerformed(ActionEvent e){
+				for(JTextArea i : jtAreas){
+					i.setText("");
+				}
+				for(JTextField i : jtFields){
+					i.setText("");
+				}
+			}
+		});
+
+		processButton.addActionListener(new ActionListener(){
+			@Override
+			public void actionPerformed(ActionEvent e){
+				String request = String.format("%s&%s&%s&%s&%s",jtFields[0].getText(),jtFields[1].getText(),jtAreas[0].getText(),jtFields[2].getText(),jtAreas[1].getText());
+				
+				jl.setText(sendRequest(request));
+			}
+		});
+
+		JRootPane rootPane = SwingUtilities.getRootPane(processButton); 
+		rootPane.setDefaultButton(processButton);
+		setVisible(true);
+	} 
+	public void setFilterManager(FilterManager filterManager){
+		this.filterManager = filterManager;
+	}
+	public String sendRequest(String request){
+		return filterManager.filterRequest(request);
+	}
+}

intercepting-filter/src/main/java/com/iluwatar/ContactFilter.java

@@ -0,0 +1,14 @@
+package com.iluwatar;
+/**
+ * Concrete implementation of filter
+ * This filter checks for the contact field in which it checks if the input consist of numbers and it also checks if the input follows the length constraint (11 digits)
+ * @author joshzambales
+ *
+ */
+public class ContactFilter implements Filter{
+	public String execute(String[] request){
+		if(request[1].equals("") || request[1].matches(".*[^\\d]+.*") || request[1].length() != 11){
+			return null;
+		}else return request[1];
+	}
+}

intercepting-filter/src/main/java/com/iluwatar/DepositFilter.java

@@ -0,0 +1,15 @@
+package com.iluwatar;
+/**
+ * Concrete implementation of filter
+*
+ * This checks for the deposit code, returns null when deposit field is empty 
+ * @author joshzambales
+ *
+ */
+public class DepositFilter implements Filter{
+	public String execute(String[] request){
+		if(request[3].equals("")){
+			return null;
+		}else return request[3];
+	}
+}

intercepting-filter/src/main/java/com/iluwatar/Filter.java

@@ -0,0 +1,11 @@
+package com.iluwatar;
+/**
+* Filter interface 
+ * Filters perform certain tasks prior or after execution of request by request handler.
+ * In this case, before the request is handled by the target, the request undergoes through each Filter
+ * @author joshzambales
+ *
+ */
+public interface Filter{
+	public String execute(String[] request);
+}

intercepting-filter/src/main/java/com/iluwatar/FilterChain.java

@@ -0,0 +1,49 @@
+ package com.iluwatar;
+ import java.util.*;
+/**
+ * Filter Chain carries multiple filters and help to execute them in defined order on target.
+ * 
+ * @author joshzambales
+ */
+public class FilterChain{
+	private ArrayList<Filter> filters = new ArrayList<Filter>();
+	private final Target target;
+
+	public FilterChain(Target target){
+		this.target = target;
+	}
+	public void addFilter(Filter filter){
+		filters.add(filter);
+	}
+
+	public String execute(String request){
+		String tempout[] = new String[filters.size()];
+
+		String tempin[] = request.split("&");
+		int i = 0;
+		try{
+			for(Filter filter:filters){
+				tempout[i] = null;
+				tempout[i++] = filter.execute(tempin);
+			}
+		}catch(Exception e){
+			return "NOT ENOUGHT INPUT";
+		}
+		
+		if(tempout[4] == null){
+			return "INVALID ORDER!";
+		}else if(tempout[3] == null){
+			return "INVALID DEPOSIT NUMBER!";
+		}else if(tempout[2] == null){
+			return "INVALID ADRDESS!";
+		}else if(tempout[1] == null){
+			return "INVALID Contact Number!";
+		}else if(tempout[0] == null){
+			return "INVALID Name!";
+		}else{
+			target.execute(tempout);
+			return "RUNNING...";
+		}
+	}
+
+}

intercepting-filter/src/main/java/com/iluwatar/FilterManager.java

@@ -0,0 +1,24 @@
+ package com.iluwatar;
+ import java.util.*;
+import javax.swing.*;
+import javax.swing.table.*;
+import java.awt.*;
+import java.awt.event.*;
+/**
+ *  Filter Manager manages the filters and Filter Chain. 
+ * @author joshzambales
+ *
+ */
+public class FilterManager{
+	private FilterChain filterChain;
+	
+	public FilterManager(Target target){		
+		filterChain = new FilterChain(target);
+	}
+	public void setFilter(Filter filter){
+		filterChain.addFilter(filter);
+	}
+	public String filterRequest(String request){
+		return filterChain.execute(request);
+	}
+}

intercepting-filter/src/main/java/com/iluwatar/NameFilter.java

@@ -0,0 +1,14 @@
+package com.iluwatar;
+/**
+ * Concrete implementation of filter
+ * This filter checks if the input in the Name field is valid. (alphanumeric) 
+ * @author joshzambales
+ *
+ */
+public class NameFilter implements Filter{
+	public String execute(String[] request){
+		if(request[0].equals("") || request[0].matches(".*[^\\w|\\s]+.*")){
+			return null;
+		}else return request[0];
+	}
+}

intercepting-filter/src/main/java/com/iluwatar/OrderFilter.java

@@ -0,0 +1,15 @@
+package com.iluwatar;
+/**
+ * Concrete implementation of filter
+ * This checks for the order field, returns null when order field is empty 
+ * 
+ * @author joshzambales
+ *
+ */
+public class OrderFilter implements Filter{
+	public String execute(String[] request){
+		if(request[4].equals("")){
+			return null;
+		}else return request[4];
+	}
+}

intercepting-filter/src/main/java/com/iluwatar/Target.java

@@ -0,0 +1,59 @@
+ package com.iluwatar;
+ import java.util.*;
+import javax.swing.*;
+import javax.swing.table.*;
+import java.awt.*;
+import java.awt.event.*;
+/**
+ * This is where the requests are displayed after being validated by filters. 
+ * 
+ * @author mjoshzambales
+ *
+ */
+public class Target extends JFrame{
+	private JTable jt;
+	private JScrollPane jsp;
+	private DefaultTableModel dtm;
+	private JButton del;
+	public Target(){
+		super("Order System");
+		setDefaultCloseOperation(EXIT_ON_CLOSE);
+		setSize(640,480);
+		dtm = new DefaultTableModel(new Object[]{"Name", "Contact Number", "Address", "Deposit Number", "Order"},0);
+		jt = new JTable(dtm);
+		del = new JButton("Delete");
+		setup();
+	}
+	private void setup(){
+		setLayout(new BorderLayout());
+		JPanel bot = new JPanel();
+		add(jt.getTableHeader(), BorderLayout.NORTH);
+		bot.setLayout(new BorderLayout());
+		bot.add(del, BorderLayout.EAST);
+		add(bot, BorderLayout.SOUTH);
+		jsp = new JScrollPane(jt);
+		jsp.setPreferredSize(new Dimension(500,250));
+		add(jsp, BorderLayout.CENTER);
+
+		del.addActionListener(new DListener());
+
+		JRootPane rootPane = SwingUtilities.getRootPane(del); 
+		rootPane.setDefaultButton(del);
+		setVisible(true);
+	}
+	public void execute(String[] request){
+		dtm.addRow(new Object[]{request[0],request[1],request[2],request[3],request[4]});
+	}
+
+	class DListener implements ActionListener{
+		@Override
+		public void actionPerformed(ActionEvent e){
+			int temp = jt.getSelectedRow();
+			if(temp == -1) return;
+			int temp2 = jt.getSelectedRowCount();
+			for(int i = 0; i < temp2; i++){
+				dtm.removeRow(temp);
+			}
+		}
+	}
+}

pom.xml

@@ -43,6 +43,7 @@
 		<module>callback</module>
 		<module>execute-around</module>
 		<module>property</module>
+		<module>intercepting-filter</module>
 	</modules>
 
 	<dependencyManagement>