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package com.sun.xml.ws.api.server;
import com.sun.xml.ws.api.config.management.Reconfigurable;
import com.sun.xml.ws.api.Component;
import com.sun.xml.ws.api.pipe.Codec;
import com.sun.xml.ws.api.message.Packet;
import com.sun.xml.ws.api.server.WSEndpoint.PipeHead;
import com.sun.xml.ws.util.Pool;
/**
* Receives incoming messages from a transport (such as HTTP, JMS, etc)
* in a transport specific way, and delivers it to {@link WSEndpoint.PipeHead#process}.
*
* <p>
* Since this class mostly concerns itself with converting a
* transport-specific message representation to a {@link Packet},
* the name is the "adapter".
*
* <p>
* The purpose of this class is twofolds:
*
* <ol>
* <li>
* To hide the logic of converting a transport-specific connection
* to a {@link Packet} and do the other way around.
*
* <li>
* To manage thread-unsafe resources, such as {@link WSEndpoint.PipeHead},
* and {@link Codec}.
* </ol>
*
* <p>
* {@link Adapter}s are extended to work with each kind of transport,
* and therefore {@link Adapter} class itself is not all that
* useful by itself --- it merely provides a design template
* that can be followed.
*
* <p>
* For managing resources, an adapter uses an object called {@link Toolkit}
* (think of it as a tray full of tools that a dentist uses ---
* trays are identical, but each patient has to get one. You have
* a pool of them and you assign it to a patient.)
*
* {@link Adapter.Toolkit} can be extended by derived classes.
* That actual type is the {@code TK} type parameter this class takes.
*
* @author Kohsuke Kawaguchi
*/
public abstract class Adapter<TK extends Adapter.Toolkit>
implements Reconfigurable, Component {
protected final WSEndpoint<?> endpoint;
/**
* Object that groups all thread-unsafe resources.
*/
public class Toolkit {
/**
* For encoding/decoding infoset to/from the byte stream.
*/
public final Codec codec;
/**
* This object from {@link WSEndpoint} serves the request.
*/
public final PipeHead head;
public Toolkit() {
this.codec = endpoint.createCodec();
this.head = endpoint.createPipeHead();
}
}
/**
* Pool of {@link Toolkit}s.
*
* Instances of this pool may be replaced at runtime. Therefore, when you take
* an object out of the pool, you must make sure that it is recycled by the
* same instance of the pool.
*/
protected volatile Pool<TK> pool = new Pool<TK>() {
protected TK create() {
return createToolkit();
}
};
/**
* Creates an {@link Adapter} that delivers
* messages to the given endpoint.
*/
protected Adapter(WSEndpoint endpoint) {
assert endpoint!=null;
this.endpoint = endpoint;
// Enables other components to reconfigure this adapter
endpoint.getComponents().add(getEndpointComponent());
}
protected Component getEndpointComponent() {
return new Component() {
public <S> S getSPI(Class<S> spiType) {
if (spiType.isAssignableFrom(Reconfigurable.class)) {
return spiType.cast(Adapter.this);
}
return null;
}
};
}
/**
* The pool instance needs to be recreated to prevent reuse of old Toolkit instances.
*/
public void reconfigure() {
this.pool = new Pool<TK>() {
protected TK create() {
return createToolkit();
}
};
}
public <S> S getSPI(Class<S> spiType) {
if (spiType.isAssignableFrom(Reconfigurable.class)) {
return spiType.cast(this);
}
if (endpoint != null) {
return endpoint.getSPI(spiType);
}
return null;
}
/**
* Gets the endpoint that this {@link Adapter} is serving.
*
* @return
* always non-null.
*/
public WSEndpoint<?> getEndpoint() {
return endpoint;
}
/**
* Returns a reference to the pool of Toolkits for this adapter.
*
* The pool may be recreated during runtime reconfiguration and this method
* will then return a reference to a new instance. When you recycle a toolkit,
* you must make sure that you return it to the same pool instance that you
* took it from.
*
* @return
*/
protected Pool<TK> getPool() {
return pool;
}
/**
* Creates a {@link Toolkit} instance.
*
* <p>
* If the derived class doesn't have to add any per-thread state
* to {@link Toolkit}, simply implement this as {@code new Toolkit()}.
*/
protected abstract TK createToolkit();
}