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[refactor] Remove unnecessary declarations in service-locator pattern.

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This commit is contained in:
ruslanpa 2015-02-10 10:02:44 +02:00
parent 4b432a79d9
commit 14058082bb
6 changed files with 119 additions and 120 deletions
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24
service-locator/src/main/java/com/iluwatar/App.java
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@ -1,20 +1,20 @@
package com.iluwatar; package com.iluwatar;
/** /**
* Service locator pattern, used to lookup jndi services * Service locator pattern, used to lookup jndi services
* and cache them for subsequent requests. * and cache them for subsequent requests.
* @author saifasif
* *
* @author saifasif
*/ */
public class App { public class App {
public static void main(String[] args) { public static void main(String[] args) {
Service service = ServiceLocator.getService("jndi/serviceA"); Service service = ServiceLocator.getService("jndi/serviceA");
service.execute(); service.execute();
service = ServiceLocator.getService("jndi/serviceB"); service = ServiceLocator.getService("jndi/serviceB");
service.execute(); service.execute();
service = ServiceLocator.getService("jndi/serviceA"); service = ServiceLocator.getService("jndi/serviceA");
service.execute(); service.execute();
service = ServiceLocator.getService("jndi/serviceA"); service = ServiceLocator.getService("jndi/serviceA");
service.execute(); service.execute();
} }
} }

38
service-locator/src/main/java/com/iluwatar/InitContext.java
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@ -3,27 +3,27 @@ package com.iluwatar;
/** /**
* For JNDI lookup of services from the web.xml. Will match name of the service name that * For JNDI lookup of services from the web.xml. Will match name of the service name that
* is being requested and return a newly created service object with the name * is being requested and return a newly created service object with the name
* @author saifasif
* *
* @author saifasif
*/ */
public class InitContext { public class InitContext {
/** /**
* Perform the lookup based on the service name. The returned object will need to be * Perform the lookup based on the service name. The returned object will need to be
* casted into a {@link Service} * casted into a {@link Service}
* @param serviceName *
* @return * @param serviceName a string
*/ * @return an {@link Object}
public Object lookup(String serviceName){ */
if( serviceName.equals("jndi/serviceA") ){ public Object lookup(String serviceName) {
System.out.println("Looking up service A and creating new service for A"); if (serviceName.equals("jndi/serviceA")) {
return new ServiceImpl("jndi/serviceA"); System.out.println("Looking up service A and creating new service for A");
} else if( serviceName.equals("jndi/serviceB") ){ return new ServiceImpl("jndi/serviceA");
System.out.println("Looking up service B and creating new service for B"); } else if (serviceName.equals("jndi/serviceB")) {
return new ServiceImpl("jndi/serviceB"); System.out.println("Looking up service B and creating new service for B");
} else { return new ServiceImpl("jndi/serviceB");
return null; } else {
} return null;
} }
}
} }

7
service-locator/src/main/java/com/iluwatar/Service.java
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@ -14,16 +14,15 @@ public interface Service {
/* /*
* The human readable name of the service * The human readable name of the service
*/ */
public String getName(); String getName();
/* /*
* Unique ID of the particular service * Unique ID of the particular service
*/ */
public int getId(); int getId();
/* /*
* The workflow method that defines what this service does * The workflow method that defines what this service does
*/ */
public void execute(); void execute();
} }

57
service-locator/src/main/java/com/iluwatar/ServiceCache.java
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@ -8,39 +8,40 @@ import java.util.Map;
* On first hit, the cache will be empty and thus any service that is being requested, will be * On first hit, the cache will be empty and thus any service that is being requested, will be
* created fresh and then placed into the cache map. On next hit, if same service name will * created fresh and then placed into the cache map. On next hit, if same service name will
* be requested, it will be returned from the cache * be requested, it will be returned from the cache
* @author saifasif
* *
* @author saifasif
*/ */
public class ServiceCache { public class ServiceCache {
private Map<String, Service> serviceCache; private final Map<String, Service> serviceCache;
public ServiceCache() { public ServiceCache() {
serviceCache = new HashMap<String, Service>(); serviceCache = new HashMap<String, Service>();
} }
/** /**
* Get the service from the cache. null if no service is found matching the * Get the service from the cache. null if no service is found matching the name
* name *
* @param serviceName * @param serviceName a string
* @return {@link Service} * @return {@link Service}
*/ */
public Service getService(String serviceName){ public Service getService(String serviceName) {
Service cachedService = null; Service cachedService = null;
for (String serviceJndiName : serviceCache.keySet()){ for (String serviceJndiName : serviceCache.keySet()) {
if( serviceJndiName.equals( serviceName ) ){ if (serviceJndiName.equals(serviceName)) {
cachedService = serviceCache.get(serviceJndiName); cachedService = serviceCache.get(serviceJndiName);
System.out.println("(cache call) Fetched service " + cachedService.getName() + "("+cachedService.getId()+") from cache... !"); System.out.println("(cache call) Fetched service " + cachedService.getName() + "(" + cachedService.getId() + ") from cache... !");
} }
} }
return cachedService; return cachedService;
} }
/** /**
* Adds the service into the cache map * Adds the service into the cache map
* @param newService *
*/ * @param newService a {@link Service}
public void addService(Service newService){ */
serviceCache.put(newService.getName(), newService); public void addService(Service newService) {
} serviceCache.put(newService.getName(), newService);
}
} }

42
service-locator/src/main/java/com/iluwatar/ServiceImpl.java
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@ -4,34 +4,34 @@ package com.iluwatar;
* This is a single service implementation of a sample service. This is the actual * This is a single service implementation of a sample service. This is the actual
* service that will process the request. The reference for this service is to * service that will process the request. The reference for this service is to
* be looked upon in the JNDI server that can be set in the web.xml deployment descriptor * be looked upon in the JNDI server that can be set in the web.xml deployment descriptor
* @author saifasif
* *
* @author saifasif
*/ */
public class ServiceImpl implements Service { public class ServiceImpl implements Service {
private String serviceName; private final String serviceName;
private int id; private final int id;
public ServiceImpl(String serviceName) { public ServiceImpl(String serviceName) {
// set the service name // set the service name
this.serviceName = serviceName; this.serviceName = serviceName;
// Generate a random id to this service object // Generate a random id to this service object
this.id = (int)Math.floor(Math.random()*1000)+1; this.id = (int) Math.floor(Math.random() * 1000) + 1;
} }
@Override @Override
public String getName() { public String getName() {
return serviceName; return serviceName;
} }
@Override @Override
public int getId() { public int getId() {
return id; return id;
} }
@Override @Override
public void execute() { public void execute() {
System.out.println("Service " + getName() + " is now executing with id " + getId()); System.out.println("Service " + getName() + " is now executing with id " + getId());
} }
} }

45
service-locator/src/main/java/com/iluwatar/ServiceLocator.java
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@ -5,33 +5,32 @@ package com.iluwatar;
* Will fetch service from cache, otherwise creates a fresh service and update cache * Will fetch service from cache, otherwise creates a fresh service and update cache
* *
* @author saifasif * @author saifasif
*
*/ */
public class ServiceLocator { public class ServiceLocator {
private static ServiceCache serviceCache = new ServiceCache(); private static ServiceCache serviceCache = new ServiceCache();
/** /**
* Fetch the service with the name param from the cache first, * Fetch the service with the name param from the cache first,
* if no service is found, lookup the service from the {@link InitContext} and * if no service is found, lookup the service from the {@link InitContext} and
* then add the newly created service into the cache map for future requests. * then add the newly created service into the cache map for future requests.
* @param serviceJndiName *
* @return {@link Service} * @param serviceJndiName a string
*/ * @return {@link Service}
public static Service getService(String serviceJndiName){ */
Service serviceObj = serviceCache.getService(serviceJndiName); public static Service getService(String serviceJndiName) {
if ( serviceObj != null ){ Service serviceObj = serviceCache.getService(serviceJndiName);
return serviceObj; if (serviceObj != null) {
} else { return serviceObj;
/* } else {
* If we are unable to retrive anything from cache, then /*
* If we are unable to retrive anything from cache, then
* lookup the service and add it in the cache map * lookup the service and add it in the cache map
*/ */
InitContext ctx = new InitContext(); InitContext ctx = new InitContext();
serviceObj = (Service) ctx.lookup(serviceJndiName); serviceObj = (Service) ctx.lookup(serviceJndiName);
serviceCache.addService(serviceObj); serviceCache.addService(serviceObj);
return serviceObj; return serviceObj;
} }
} }
} }