org.jboss.weld.interceptor.proxy.SimpleInterceptionChain Maven / Gradle / Ivy

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/*
 * JBoss, Home of Professional Open Source
 * Copyright 2009, Red Hat, Inc. and/or its affiliates, and individual
 * contributors by the @authors tag. See the copyright.txt in the
 * distribution for a full listing of individual contributors.
 *
 * Licensed 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.jboss.weld.interceptor.proxy;

import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;

import javax.interceptor.InvocationContext;

import org.jboss.weld.injection.Exceptions;
import org.jboss.weld.interceptor.spi.context.InterceptionChain;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * @author Marius Bogoevici
 */
public class SimpleInterceptionChain implements InterceptionChain {

    private static final Logger log = LoggerFactory.getLogger(SimpleInterceptionChain.class);

    private final Object target;

    private final Method targetMethod;

    private int currentPosition;

    private final List interceptorMethodInvocations;

    public SimpleInterceptionChain(Collection interceptorInvocations, Object target, Method targetMethod) {
        this.target = target;
        this.targetMethod = targetMethod;
        this.currentPosition = 0;
        interceptorMethodInvocations = new ArrayList();
        for (InterceptorInvocation interceptorInvocation : interceptorInvocations) {
            interceptorMethodInvocations.addAll(interceptorInvocation.getInterceptorMethodInvocations());
        }
    }

    public Object invokeNextInterceptor(InvocationContext invocationContext) throws Throwable {

        try {
            if (hasNextInterceptor()) {
                int oldCurrentPosition = currentPosition;
                try {
                    InterceptorMethodInvocation nextInterceptorMethodInvocation = interceptorMethodInvocations.get(currentPosition++);
                    if (log.isTraceEnabled()) {
                        log.trace("Invoking next interceptor in chain:" + nextInterceptorMethodInvocation.toString());
                    }
                    if (nextInterceptorMethodInvocation.expectsInvocationContext()) {
                        return nextInterceptorMethodInvocation.invoke(invocationContext);
                    } else {
                        nextInterceptorMethodInvocation.invoke(null);
                        while (hasNextInterceptor()) {
                            nextInterceptorMethodInvocation = interceptorMethodInvocations.get(currentPosition++);
                            nextInterceptorMethodInvocation.invoke(null);
                        }
                        return null;
                    }
                } finally {
                    currentPosition = oldCurrentPosition;
                }
            } else {
                if (targetMethod != null) {
                    targetMethod.setAccessible(true);
                    if (invocationContext.getMethod() != null) {
                        return targetMethod.invoke(target, invocationContext.getParameters());
                    } else {
                        return targetMethod.invoke(target);
                    }

                } else {
                    return null;
                }
            }
        } catch (InvocationTargetException e) {
            throw Exceptions.unwrapIfPossible(e);
        }
    }

    private void validateInterceptor(SimpleMethodInvocation nextInterceptorMethodInvocation, InvocationContext context) {
        int expectedParameters = context == null ? 0 : 1;
        if (nextInterceptorMethodInvocation.method.getJavaMethod().getParameterTypes().length != expectedParameters) {
            throw new IllegalStateException(
                    "Mismatch between number of expected and actual parameters on "
                            + nextInterceptorMethodInvocation.getMethod() + ": expected " + expectedParameters
                            + ", actual " + nextInterceptorMethodInvocation.getMethod().getJavaMethod().getParameterTypes().length);
        }
    }

    public boolean hasNextInterceptor() {
        return currentPosition < interceptorMethodInvocations.size();
    }

}