/*
 * 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.struts2.interceptor;

import com.opensymphony.xwork2.ActionContext;
import com.opensymphony.xwork2.interceptor.ParametersInterceptor;
import org.apache.struts2.ServletActionContext;
import org.apache.struts2.dispatcher.HttpParameters;
import org.apache.struts2.dispatcher.mapper.ActionMapping;

import java.util.Map;

/**
 * <!-- START SNIPPET: description -->
 * <p>
 * This interceptor sets all parameters from the action mapping, for this request, on the value stack.  It operates
 * exactly like {@link ParametersInterceptor}, only the parameters come from the {@link ActionMapping}, not the
 * {@link ActionContext#getParameters()} method.
 * </p>
 *
 * <!-- END SNIPPET: description -->
 *
 * <p><u>Interceptor parameters:</u></p>
 *
 * <!-- START SNIPPET: parameters -->
 *
 * <ul>
 *
 * <li>ordered - set to true if you want the top-down property setter behaviour</li>
 *
 * </ul>
 *
 * <!-- END SNIPPET: parameters -->
 *
 * <p><u>Extending the interceptor:</u></p>
 *
 * <!-- START SNIPPET: extending -->
 *
 * <p>
 * The best way to add behavior to this interceptor is to utilize the {@link com.opensymphony.xwork2.interceptor.ParameterNameAware} interface in your
 * actions. However, if you wish to apply a global rule that isn't implemented in your action, then you could extend
 * this interceptor and override the {@link #acceptableName(String)} method.
 * </p>
 *
 * <!-- END SNIPPET: extending -->
 *
 * <p><u>Example code:</u></p>
 *
 * <pre>
 * <!-- START SNIPPET: example -->
 * &lt;action name="someAction" class="com.examples.SomeAction"&gt;
 *     &lt;interceptor-ref name="mappingParams"/&gt;
 *     &lt;result name="success"&gt;good_result.ftl&lt;/result&gt;
 * &lt;/action&gt;
 * <!-- END SNIPPET: example -->
 * </pre>
 */
public class ActionMappingParametersInterceptor extends ParametersInterceptor {

    /**
     * Get the parameter map from ActionMapping associated with the provided ActionContext.
     * 
     * @param ac The action context
     * @return the parameters from the action mapping in the context.  If none found, returns an empty map.
     */
    @Override
    protected HttpParameters retrieveParameters(ActionContext ac) {
        ActionMapping mapping = ac.getActionMapping();
        if (mapping != null) {
            return HttpParameters.create(mapping.getParams()).buildNoNestedWrapping();
        } else {
            return HttpParameters.create().buildNoNestedWrapping();
        }
    }

    /**
     * Adds the parameters into the current ActionContext's parameter map.
     *
     * Note: The method should avoid re-wrapping values which are already of type Parameter.
     *
     * @param ac        The action context
     * @param newParams The parameter map to apply
     */
    @Override
    protected void addParametersToContext(ActionContext ac, Map<String, ?> newParams) {
        HttpParameters previousParams = ac.getParameters();
        HttpParameters.Builder combinedParams = HttpParameters.create().withParent(previousParams).withExtraParams(newParams);

        ac.setParameters(combinedParams.buildNoNestedWrapping());
    }
}
