Struts example source code file (ParameterRemoverInterceptor.java)

This example Struts source code file (ParameterRemoverInterceptor.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Struts tags/keywords

abstractinterceptor, actioncontext, exception, exception, failed, log, map, noparameters, object, override, set, set, string, string, util

The Struts ParameterRemoverInterceptor.java source code

/*
 * Copyright 2002-2007,2009 The Apache Software Foundation.
 * 
 * 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 com.opensymphony.xwork2.interceptor;

import com.opensymphony.xwork2.ActionContext;
import com.opensymphony.xwork2.ActionInvocation;
import com.opensymphony.xwork2.util.TextParseUtil;
import com.opensymphony.xwork2.util.logging.Logger;
import com.opensymphony.xwork2.util.logging.LoggerFactory;

import java.util.Collections;
import java.util.Map;
import java.util.Set;

/**
 * <!-- START SNIPPET: description -->
 * This is a simple XWork interceptor that allows parameters (matching
 * one of the paramNames attribute csv value) to be 
 * removed from the parameter map if they match a certain value
 * (matching one of the paramValues attribute csv value), before they 
 * are set on the action. A typical usage would be to want a dropdown/select 
 * to map onto a boolean value on an action. The select had the options 
 * none, yes and no with values -1, true and false. The true and false would 
 * map across correctly. However the -1 would be set to false. 
 * This was not desired as one might needed the value on the action to stay null. 
 * This interceptor fixes this by preventing the parameter from ever reaching 
 * the action.
 * <!-- END SNIPPET: description -->
 * 
 * 
 * <!-- START SNIPPET: parameters -->
 * <ul>
 * 	<li>paramNames - A comma separated value (csv) indicating the parameter name 
 * 								    whose param value should be considered that if they match any of the
 *                                     comma separated value (csv) from paramValues attribute, shall be 
 *                                     removed from the parameter map such that they will not be applied
 *                                     to the action</li>
 * 	<li>paramValues - A comma separated value (csv) indicating the parameter value that if 
 * 							      matched shall have its parameter be removed from the parameter map 
 * 							      such that they will not be applied to the action</li>
 * </ul>
 * <!-- END SNIPPET: parameters -->
 * 
 * 
 * <!-- START SNIPPET: extending -->
 * No intended extension point
 * <!-- END SNIPPET: extending -->
 * 
 * <pre>
 * <!-- START SNIPPET: example -->
 *	
 * <action name="sample" class="org.martingilday.Sample">
 * 	<interceptor-ref name="paramRemover">
 *   		<param name="paramNames">aParam,anotherParam</param>
 *   		<param name="paramValues">--,-1</param>
 * 	</interceptor-ref>
 * 	<interceptor-ref name="defaultStack" />
 * 	...
 * </action>
 *  
 * <!-- END SNIPPET: example -->
 * </pre>
 *  
 *  
 * @author martin.gilday
 */
public class ParameterRemoverInterceptor extends AbstractInterceptor {

	private static final Logger LOG = LoggerFactory.getLogger(ParameterRemoverInterceptor.class);

	private static final long serialVersionUID = 1;

	private Set<String> paramNames = Collections.emptySet();

	private Set<String> paramValues = Collections.emptySet();

	
	/**
	 * Decide if the parameter should be removed from the parameter map based on
	 * <code>paramNames and paramValues.
	 * 
	 * @see com.opensymphony.xwork2.interceptor.AbstractInterceptor
	 */
	@Override
	public String intercept(ActionInvocation invocation) throws Exception {
		if (!(invocation.getAction() instanceof NoParameters)
				&& (null != this.paramNames)) {
			ActionContext ac = invocation.getInvocationContext();
			final Map<String, Object> parameters = ac.getParameters();

			if (parameters != null) {
                for (String removeName : paramNames) {
                    // see if the field is in the parameter map
                    if (parameters.containsKey(removeName)) {

                        try {
                            String[] values = (String[]) parameters
                                    .get(removeName);
                            String value = values[0];
                            if (null != value && this.paramValues.contains(value)) {
                                parameters.remove(removeName);
                            }
                        } catch (Exception e) {
                            LOG.error("Failed to convert parameter to string", e);
                        }
                    }
                }
			}
		}
		return invocation.invoke();
	}

	/**
	 * Allows <code>paramNames attribute to be set as comma-separated-values (csv).
	 * 
	 * @param paramNames the paramNames to set
	 */
	public void setParamNames(String paramNames) {
		this.paramNames = TextParseUtil.commaDelimitedStringToSet(paramNames);
	}


	/**
	 * Allows <code>paramValues attribute to be set as a comma-separated-values (csv).
	 * 
	 * @param paramValues the paramValues to set
	 */
	public void setParamValues(String paramValues) {
		this.paramValues = TextParseUtil.commaDelimitedStringToSet(paramValues);
	}
}