/*
 * 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.util.List;

import org.apache.tuscany.sca.interfacedef.Operation;
import org.apache.tuscany.sca.invocation.Interceptor;
import org.apache.tuscany.sca.invocation.Invoker;
import org.apache.tuscany.sca.invocation.Message;
import org.apache.tuscany.sca.policy.util.PolicyHandler;

/**
 * An interceptor to invoke policy handlers before and after the invocation of operations on 
 * an implementation.
 *
 * @version $Rev$ $Date$
 */
public class PolicyHandlingInterceptor implements Interceptor {
    private Invoker next;
    private List<PolicyHandler> policyHandlers = null;
    private Operation targetOperation = null;

    public PolicyHandlingInterceptor(Operation targetOperation, List<PolicyHandler> policyHandlers) {
        this.policyHandlers = policyHandlers;
        this.targetOperation = targetOperation;
    }

    public Message invoke(Message msg) {
        try {
            applyPreInvocationPolicies(targetOperation, msg);
            msg = next.invoke(msg);
        } finally {
            applyPostInvocationPolices(targetOperation, msg);
        }
        return msg;
    }

    public void setNext(Invoker next) {
        this.next = next;
    }

    public Invoker getNext() {
        return next;
    }

    private void applyPreInvocationPolicies(Object... context) {
        for (PolicyHandler policyHandler : policyHandlers) {
            policyHandler.beforeInvoke(context);
        }
    }

    private void applyPostInvocationPolices(Object... context) {
        for ( int count = policyHandlers.size() - 1 ; count >= 0 ; --count) {
            policyHandlers.get(count).afterInvoke(context);
        }
    }
}