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/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package org.apache.tuscany.sca.core.invocation.impl;
import java.util.List;
import java.util.concurrent.ConcurrentHashMap;
import javax.xml.namespace.QName;
import org.apache.tuscany.sca.assembly.Implementation;
import org.apache.tuscany.sca.assembly.Property;
import org.apache.tuscany.sca.assembly.Reference;
import org.apache.tuscany.sca.assembly.Service;
import org.apache.tuscany.sca.core.invocation.AsyncFaultWrapper;
import org.apache.tuscany.sca.core.invocation.AsyncResponseHandler;
import org.apache.tuscany.sca.core.invocation.Constants;
import org.apache.tuscany.sca.interfacedef.Operation;
import org.apache.tuscany.sca.invocation.Invoker;
import org.apache.tuscany.sca.invocation.Message;
import org.apache.tuscany.sca.policy.ExtensionType;
import org.apache.tuscany.sca.policy.Intent;
import org.apache.tuscany.sca.policy.PolicySet;
import org.apache.tuscany.sca.provider.ImplementationProvider;
import org.apache.tuscany.sca.runtime.RuntimeComponentService;
/**
* A class intended to form the final link in the chain calling into a Future which represents
* the response to an asynchronous service invocation
*
* Most methods are dummies, required to fulfil the contracts for ImplementationProvider, Implementation
* and Invoker, since this class collapses together the functions of these separate interfaces, due to its
* specialized nature, where most of the function will never be used.
*
* The class acts as the implementation object that terminates the chain - and also as the provider of the implementation.
* The class accepts Future objects which represent individual invocations of forward operations on the async service
* and expects that the responses it handles as invocations will carry the unique ID of one of the Future objects in the
* message header. On receipt of each message, the class seeks out the Future with that unique ID and completes the future
* either with a response message or with a Fault.
*
* @param <V>
*/
public class AsyncResponseHandlerImpl<V> implements AsyncResponseHandler<V>,
ImplementationProvider, Implementation, Invoker {
private ConcurrentHashMap< String, AsyncInvocationFutureImpl<?> > table =
new ConcurrentHashMap< String, AsyncInvocationFutureImpl<?> >();
/**
* This class is its own invoker...
*/
public Invoker createInvoker(RuntimeComponentService service,
Operation operation) {
return this;
}
/**
* Add a future to this response handler
* @param future - the future
*/
public void addFuture( AsyncInvocationFutureImpl<?> future ) {
// The Future is stored in the table indexed by its unique ID
table.put(future.getUniqueID(), future);
} // end method addFuture
public boolean supportsOneWayInvocation() {
return true;
}
public void start() {}
public void stop() {}
public List<Operation> getOperations() {
return null;
}
public QName getType() {
return null;
}
public List<Property> getProperties() {
return null;
}
public Property getProperty(String name) {
return null;
}
public Reference getReference(String name) {
return null;
}
public List<Reference> getReferences() {
return null;
}
public Service getService(String name) {
return null;
}
public List<Service> getServices() {
return null;
}
public String getURI() {
return null;
}
public void setURI(String uri) {}
public boolean isUnresolved() {
return false;
}
public void setUnresolved(boolean unresolved) {}
public ExtensionType getExtensionType() {
return null;
}
public List<PolicySet> getPolicySets() {
return null;
}
public List<Intent> getRequiredIntents() {
return null;
}
public void setExtensionType(ExtensionType type) {}
public void setWrappedFault(AsyncFaultWrapper e) {}
public void setFault(Throwable e) {}
public void setResponse(V res) { }
/**
* Method which is the termination for the invocation chain from the callback endpoint
* @param msg - the Tuscany message containing the response from the async service invocation
* which is either the Response message or an exception of some kind
*/
@SuppressWarnings({ "unchecked", "rawtypes" })
public Message invoke(Message msg) {
// Get the unique ID from the RELATES_TO message header
String idValue = (String)msg.getHeaders().get(Constants.RELATES_TO);
if( idValue == null ) {
System.out.println( "Async message ID not found ");
} else {
// Fetch the Future with that Unique ID
AsyncInvocationFutureImpl future = table.get(idValue);
if( future == null ) {
System.out.println("Future not found for id: " + idValue);
} else {
// Complete the Future with a Response message
Object payload = msg.getBody();
Object response;
if( payload == null ) {
System.out.println("Returned response message was null");
} else {
if (payload.getClass().isArray()) {
response = ((Object[])payload)[0];
} else {
response = payload;
} // end if
if( response.getClass().equals(AsyncFaultWrapper.class)) {
future.setWrappedFault((AsyncFaultWrapper) response );
} else {
future.setResponse(response);
} // end if
} // end if
} // end if
} // end if
// Prepare an empty response message
msg.setBody(null);
return msg;
} // end method invoke
} // end class
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