/*
    * Copyright 2002-2013 the original author or authors.
    *
    * 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.springframework.batch.core.listener;
  
  import java.util.Map;
  import java.util.Set;
  
  import org.aopalliance.intercept.MethodInterceptor;
  import org.aopalliance.intercept.MethodInvocation;
  import org.springframework.batch.core.ExitStatus;
  import org.springframework.batch.core.StepExecutionListener;
  import org.springframework.batch.support.MethodInvoker;
  
  /**
   * {@link MethodInterceptor} that, given a map of method names and
   * {@link MethodInvoker}s, will execute all methods tied to a particular method
   * name, with the provided arguments. The only possible return value that is
   * handled is of type ExitStatus, since the only StepListener implementation
   * that isn't void is
   * {@link StepExecutionListener#afterStep(org.springframework.batch.core.StepExecution)}
   * , which returns ExitStatus.
   *
   * @author Lucas Ward
   * @since 2.0
   * @see MethodInvoker
   */
  public class MethodInvokerMethodInterceptor implements MethodInterceptor {
  
  	private final Map<String, Set<MethodInvoker>> invokerMap;
  	private final boolean ordered;
  
  	public MethodInvokerMethodInterceptor(Map<String, Set<MethodInvoker>> invokerMap) {
  		this(invokerMap, false);
  	}
  
  	public MethodInvokerMethodInterceptor(Map<String, Set<MethodInvoker>> invokerMap, boolean ordered) {
  		this.ordered = ordered;
  		this.invokerMap = invokerMap;
  	}
  
  	@Override
  	public Object invoke(MethodInvocation invocation) throws Throwable {
  
  		String methodName = invocation.getMethod().getName();
  		if (ordered && methodName.equals("getOrder")) {
  			return invocation.proceed();
  		}
  
  		Set<MethodInvoker> invokers = invokerMap.get(methodName);
  
  		if (invokers == null) {
  			return null;
  		}
  		ExitStatus status = null;
  		for (MethodInvoker invoker : invokers) {
  			Object retVal = invoker.invokeMethod(invocation.getArguments());
  			if (retVal instanceof ExitStatus) {
  				if (status != null) {
  					status = status.and((ExitStatus) retVal);
  				}
  				else {
  					status = (ExitStatus) retVal;
  				}
  			}
  		}
  
  		// The only possible return values are ExitStatus or int (from Ordered)
  		return status;
  	}
  
  	/**
  	 * {@inheritDoc}
  	 */
  	@Override
  	public boolean equals(Object obj) {
  		if (!(obj instanceof MethodInvokerMethodInterceptor)) {
  			return false;
  		}
  		MethodInvokerMethodInterceptor other = (MethodInvokerMethodInterceptor) obj;
  		return invokerMap.equals(other.invokerMap);
  	}
  
  	/**
  	 * {@inheritDoc}
  	 */
  	@Override
 	public int hashCode() {
 		return invokerMap.hashCode();
 	}
 
 }