Adding appropriate comments on classes and full description in App.java. Removing added function in ServiceAmbassador as it's not appropriate for the example.

This commit is contained in:
Ovidijus Okinskas 2018-06-04 20:36:10 +01:00 committed by O.Okinskas
parent 73925cef2e
commit 6b10f4bdd1
5 changed files with 61 additions and 13 deletions

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@ -1,5 +1,44 @@
/**
* The MIT License
* Copyright (c) 2014-2016 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.ambassador;
/**
*
* The ambassador pattern creates a helper service that sends network requests on behalf of a
* client. It is often used in cloud-based applications to offload features of a remote service.
*
* An ambassador service can be thought of as an out-of-process proxy that is co-located with
* the client. Similar to the proxy design pattern, the ambassador service provides an interface
* for another remote service. In addition to the interface, the ambassador provides extra
* functionality and features, specifically offloaded common connectivity tasks. This usually
* consists of monitoring, logging, routing, security etc. This is extremely useful in
* legacy applications where the codebase is difficult to modify and allows for improvements
* in the application's networking capabilities.
*
* In this example, we will the ({@link ServiceAmbassador}) class represents the ambassador while the
* ({@link RemoteService}) class represents a remote application.
*
*/
public class App {
/**
@ -9,11 +48,7 @@ public class App {
Client host1 = new Client();
Client host2 = new Client();
host1.useService(12);
host2.useService(73);
host1.useNewService(12);
host2.useNewService(73);
}
}

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@ -22,6 +22,9 @@
*/
package com.iluwatar.ambassador;
/**
* A simple Client
*/
public class Client {
private ServiceAmbassador serviceAmbassador;
@ -34,9 +37,4 @@ public class Client {
long result = serviceAmbassador.doRemoteFunction(value);
System.out.println(result);
}
void useNewService(int value) {
long result = serviceAmbassador.doAddedFunction(value);
System.out.println(result);
}
}

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@ -24,6 +24,9 @@ package com.iluwatar.ambassador;
import static java.lang.Thread.sleep;
/**
* A remote legacy application represented by a Singleton implementation.
*/
public class RemoteService implements RemoteServiceInterface {
private static RemoteService service = null;
@ -39,6 +42,12 @@ public class RemoteService implements RemoteServiceInterface {
}
/**
* Remote function takes a value and multiplies it by 10 taking a random amount of time.
* Will sometimes return -1. This immitates connectivity issues a client might have to account for.
* @param value integer value to be multiplied.
* @return if waitTime is more than 200ms, it returns value * 10, otherwise -1.
*/
@Override
public long doRemoteFunction(int value) {

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@ -22,6 +22,9 @@
*/
package com.iluwatar.ambassador;
/**
* Interface shared by ({@link RemoteService}) and ({@link ServiceAmbassador}).
*/
interface RemoteServiceInterface {
long doRemoteFunction(int value) throws Exception;

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@ -27,6 +27,13 @@ import org.slf4j.LoggerFactory;
import static java.lang.Thread.sleep;
/**
*
* ServiceAmbassador provides an interface for a ({@link Client}) to access ({@link RemoteService}).
* The interface adds logging, latency testing and usage of the service in a safe way that will not
* add stress to the remote service when connectivity issues occur.
*
*/
public class ServiceAmbassador implements RemoteServiceInterface {
private static final Logger LOGGER = LoggerFactory.getLogger(ServiceAmbassador.class);
@ -43,10 +50,6 @@ public class ServiceAmbassador implements RemoteServiceInterface {
return safeCall(value);
}
long doAddedFunction(int value) {
return safeCall(value) * 5;
}
private long checkLatency(int value) {
RemoteService service = RemoteService.getRemoteService();
long startTime = System.currentTimeMillis();