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XWork is an command-pattern framework that is used to power WebWork as well as other applications. XWork provides an Inversion of Control container, a powerful expression language, data type conversion, validation, and pluggable configuration.
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/*
 * Copyright (c) 2002-2007 by OpenSymphony
 * All rights reserved.
 */
package com.opensymphony.xwork2.interceptor;

import com.opensymphony.xwork2.ActionInvocation;
import com.opensymphony.xwork2.Unchainable;
import com.opensymphony.xwork2.inject.Inject;
import com.opensymphony.xwork2.util.CompoundRoot;
import com.opensymphony.xwork2.util.ValueStack;
import com.opensymphony.xwork2.util.logging.Logger;
import com.opensymphony.xwork2.util.logging.LoggerFactory;
import com.opensymphony.xwork2.util.reflection.ReflectionProvider;

import java.util.*;


/**
 * 
 *
 * An interceptor that copies all the properties of every object in the value stack to the currently executing object,
 * except for any object that implements {@link Unchainable}. A collection of optional includes and
 * excludes may be provided to control how and which parameters are copied. Only includes or excludes may be
 * specified. Specifying both results in undefined behavior. See the javadocs for {@link ReflectionProvider#copy(Object, Object,
 * java.util.Map, java.util.Collection, java.util.Collection)} for more information.
 *
 * 
 * Note: It is important to remember that this interceptor does nothing if there are no objects already on the stack.
 * 
This means two things:
 * 
One, you can safely apply it to all your actions without any worry of adverse affects.
 * 
Two, it is up to you to ensure an object exists in the stack prior to invoking this action. The most typical way this is done
 * is through the use of the chain result type, which combines with this interceptor to make up the action
 * chaining feature.
 *
 * 
 *
 * 
 Interceptor parameters:
 *
 * 
 *
 * 

 *
 * excludes (optional) - the list of parameter names to exclude from copying (all others will be included).
 *
 * includes (optional) - the list of parameter names to include when copying (all others will be excluded).
 *
 * 
 *
 * 
 *
 *  Extending the interceptor:
 *
 * 

 *
 * 
 *
 * There are no known extension points to this interceptor.
 *
 * 
 *
 * 
 Example code:
 *
 * 
 * 
 * 
 * <action name="someAction" class="com.examples.SomeAction">
 *     <interceptor-ref name="basicStack"/>
 *     <result name="success" type="chain">otherAction</result>
 * </action>
 *
 * <action name="otherAction" class="com.examples.OtherAction">
 *     <interceptor-ref name="chain"/>
 *     <interceptor-ref name="basicStack"/>
 *     <result name="success">good_result.ftl</result>
 * </action>
 * 
 * 
 * 
 *
 * @see com.opensymphony.xwork2.ActionChainResult
 * @author mrdon
 * @author tm_jee ( tm_jee(at)yahoo.co.uk )
 */
public class ChainingInterceptor extends AbstractInterceptor {
	
	private static final Logger LOG = LoggerFactory.getLogger(ChainingInterceptor.class);
	
    protected Collection excludes;
    protected Collection includes;
    
    protected ReflectionProvider reflectionProvider;
    
    @Inject
    public void setReflectionProvider(ReflectionProvider prov) {
        this.reflectionProvider = prov;
    }

    @Override
    public String intercept(ActionInvocation invocation) throws Exception {
        ValueStack stack = invocation.getStack();
        CompoundRoot root = stack.getRoot();

        if (root.size() > 1) {
            List list = new ArrayList(root);
            list.remove(0);
            Collections.reverse(list);

            Map ctxMap = invocation.getInvocationContext().getContextMap();
            Iterator iterator = list.iterator();
            int index = 1; // starts with 1, 0 has been removed
            while (iterator.hasNext()) {
            	index = index + 1;
                Object o = iterator.next();
                if (o != null) {
                	if (!(o instanceof Unchainable)) {
                		reflectionProvider.copy(o, invocation.getAction(), ctxMap, excludes, includes);
                	}
                }
                else {
                	LOG.warn("compound root element at index "+index+" is null");
                }
            }
        }
        
        return invocation.invoke();
    }
    
    /**
     * Gets list of parameter names to exclude
     *
     * @return the exclude list
     */
    public Collection getExcludes() {
        return excludes;
    }

    /**
     * Sets the list of parameter names to exclude from copying (all others will be included).
     *
     * @param excludes  the excludes list
     */
    public void setExcludes(Collection excludes) {
        this.excludes = excludes;
    }

    /**
     * Gets list of parameter names to include
     *
     * @return the include list
     */
    public Collection getIncludes() {
        return includes;
    }

    /**
     * Sets the list of parameter names to include when copying (all others will be excluded).
     *
     * @param includes  the includes list
     */
    public void setIncludes(Collection includes) {
        this.includes = includes;
    }

}