net.java.truecommons.services

Class LocatableFactory<P>

java.lang.Object

net.java.truecommons.services.LocatableService

net.java.truecommons.services.LocatableProvider<P>

net.java.truecommons.services.LocatableFactory<P>

Type Parameters:

P - the type of the products to create.

All Implemented Interfaces:

javax.inject.Provider<P>, Factory<P>

Direct Known Subclasses:

FeedbackFactory, KeyManagerMapFactory, ObjectNameModifierFactory

@Immutable
public abstract class LocatableFactory<P>
extends LocatableProvider<P>
implements Factory<P>

A locatable provider for creating products. For best results, clients should create another abstract subclass which just specifies the type parameter P. In the following example the type parameter is specified as StringBuilder:

 package com.company.spec;

 import net.java.truecommons.services.LocatableFactory;

 public abstract class StringBuilderFactory
 extends LocatableFactory<StringBuilder> {
 }
 

An implementation could now implement this service as follows:

 package com.company.impl;

 import com.company.spec.StringBuilderFactory;

 public class GreetingFactory extends StringBuilderFactory {
     \@Override
     public StringBuilder get() {
         // Return a new instance on each call!
         return new StringBuilder("Hello Christian!");
     }
 }
 

Next, the implementation needs to advertise its service by providing a file with the name META-INF/services/com.company.spec.StringBuilderFactory on the run time class path with the following single line content:

 com.company.impl.GreetingFactory
 

If multiple factory services are locatable on the class path at run time, the service with the greatest priority gets selected.

Finally, a client could now simply compose a factory according to the StringBuilderFactory specification by calling:

 package com.company.client;

 import net.java.truecommons.services.Locator;
 import com.company.spec.StringBuilderFactory;

 public class Main {
     public static void main(String[] args) {
         Locator l = new Locator(Main.class); // specify calling class
         Factory<StringBuilder> f = l.factory(StringBuilderFactory.class);
         StringBuilder b = f.get(); // create product
         System.out.println(b.toString()); // use product
     }
 }
 

Note that multiple calls to f.get() would always return a new product because f is a factory, not a container.

Implementations should be thread-safe.

Author:

Christian Schlichtherle

See Also:

Locator

Constructor Summary

Constructors

Constructor and Description
LocatableFactory()

Method Summary

Methods inherited from class net.java.truecommons.services.LocatableService

getPriority, toString

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface net.java.truecommons.services.Factory

get

Constructor Detail

LocatableFactory

public LocatableFactory()