modules/implementation-java-runtime/src/main/java/org/apache/tuscany/sca/implementation/java/invocation/JavaImplementationInvoker.java

/*
 * 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.implementation.java.invocation;

import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;

import org.apache.tuscany.sca.assembly.EndpointReference;
import org.apache.tuscany.sca.core.factory.InstanceWrapper;
import org.apache.tuscany.sca.core.factory.ObjectCreationException;
import org.apache.tuscany.sca.core.scope.ScopeContainer;
import org.apache.tuscany.sca.core.scope.ScopedRuntimeComponent;
import org.apache.tuscany.sca.implementation.java.JavaImplementation;
import org.apache.tuscany.sca.interfacedef.DataType;
import org.apache.tuscany.sca.interfacedef.Operation;
import org.apache.tuscany.sca.interfacedef.java.impl.JavaInterfaceUtil;
import org.apache.tuscany.sca.invocation.Invoker;
import org.apache.tuscany.sca.invocation.Message;
import org.apache.tuscany.sca.runtime.RuntimeComponent;
import org.oasisopen.sca.ServiceRuntimeException;

/**
 * Responsible for synchronously dispatching an invocation to a Java component
 * implementation instance
 * 
 * @version $Rev$ $Date$
 */
public class JavaImplementationInvoker implements Invoker {
    protected Operation operation;
    protected Method method;
    protected boolean allowsPBR;

    @SuppressWarnings("unchecked")
    protected final ScopeContainer scopeContainer;

    public JavaImplementationInvoker(Operation operation, Method method, RuntimeComponent component) {
        assert method != null : "Operation method cannot be null";
        this.method = method;
        this.operation = operation;
        this.scopeContainer = ((ScopedRuntimeComponent)component).getScopeContainer();
        this.allowsPBR = ((JavaImplementation)component.getImplementation()).isAllowsPassByReference(method);
    }

    public JavaImplementationInvoker(Operation operation, RuntimeComponent component) {
        // used if the method can't be computed statically in advance 
        this.operation = operation;
        this.scopeContainer = ((ScopedRuntimeComponent)component).getScopeContainer();
    }

    @SuppressWarnings("unchecked")
    public Message invoke(Message msg) {
        Operation op = msg.getOperation();
        if (op == null) {
            op = this.operation;
        }
        Object payload = msg.getBody();

        Object contextId = null;

        EndpointReference from = msg.getFrom();

        // store the current thread context classloader
        // as we need to replace it with the class loader
        // used to load the java class as per SCA Spec
        ClassLoader tccl = Thread.currentThread().getContextClassLoader();
        
        try {
            // The following call might create a new conversation, as a result, the msg.getConversationID() might 
            // return a new value
            InstanceWrapper wrapper = scopeContainer.getWrapper(contextId);

            Object instance = wrapper.getInstance();

            // If the method couldn't be computed statically, or the instance being
            // invoked is a user-specified callback object that doesn't implement
            // the service interface from which the reflective method was obtained,
            // compute the method object dynamically for this invocation.
            Method imethod = method;
            if (imethod == null || !imethod.getDeclaringClass().isInstance(instance)) {
                try {
                    imethod = JavaInterfaceUtil.findMethod(instance.getClass(), operation);
                } catch (NoSuchMethodException e) {
                    throw new IllegalArgumentException("Callback object does not provide method " + e.getMessage());
                }
            }
            
            // Set the thread context classloader of the thread used to invoke an operation 
            // of a Java POJO component implementation is the class loader of the contribution 
            // that contains the POJO implementation class.
            
            Thread.currentThread().setContextClassLoader(instance.getClass().getClassLoader());
            
            Object ret;
            if (payload != null && !payload.getClass().isArray()) {
                ret = imethod.invoke(instance, payload);
            } else {
                ret = imethod.invoke(instance, (Object[])payload);
            }

            scopeContainer.returnWrapper(wrapper, contextId);
            
            msg.setBody(ret);
        } catch (InvocationTargetException e) {
            Throwable cause = e.getTargetException();
            boolean isChecked = false;
            for (DataType<?> d : operation.getFaultTypes()) {
                if (d.getPhysical().isInstance(cause)) {
                    isChecked = true;
                    msg.setFaultBody(cause);
                    break;
                }
            } 
            
            if (!isChecked) {
                if (cause instanceof RuntimeException) {
                    throw (RuntimeException)cause;
                }
                if (cause instanceof Error) {
                    throw (Error)cause;
                } else {
                    throw new ServiceRuntimeException(cause.getMessage(), cause);
                }
            }            
                
        } catch (ObjectCreationException e) {
            throw new ServiceRuntimeException(e.getMessage(), e);
        } catch (Exception e) {
            msg.setFaultBody(e);           
        } finally {
            // set the tccl 
            Thread.currentThread().setContextClassLoader(tccl);
        }
        return msg;
    }

}