/*
* $Id: AbstractMappingDispatcher.java 729832 2008-12-29 05:12:58Z pbenedict $
*
* 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.struts.dispatcher;
import org.apache.struts.action.ActionMapping;
import org.apache.struts.chain.contexts.ActionContext;
/**
* This abstract class is a template for choosing the target method that is
* named by the <code>parameter</code> attribute of the corresponding
* {@link ActionMapping}. The attribute value, if not provided, defaults to
* <code>execute</code>.
*
* @version $Rev: 729832 $
* @since Struts 1.4
*/
public abstract class AbstractMappingDispatcher extends AbstractDispatcher {
private String defaultMappingParameter;
/**
* Constructs a new dispatcher with the specified method resolver.
*
* @param methodResolver the method resolver
*/
public AbstractMappingDispatcher(MethodResolver methodResolver) {
super(methodResolver);
setDefaultMappingParameter(EXECUTE_METHOD_NAME);
}
/**
* Retrieves the default mapping parameter value. This value is used by
* {@link #resolveMethodName(ActionContext)} if the mapping did not provide
* a value.
*
* @return the mapping parameter value or <code>null</code>
* @see #setDefaultMappingParameter(String)
*/
protected final String getDefaultMappingParameter() {
return defaultMappingParameter;
}
/**
* Resolves the method name by obtaining the <code>parameter</code>
* attribute from the {@link ActionMapping}.
*
* @param context {@inheritDoc}
* @throws IllegalStateException if the parameter cannot be resolved
* @return the parameter attribute value
*/
protected String resolveMethodName(ActionContext context) {
// Null out an empty string parameter
ActionMapping mapping = (ActionMapping) context.getActionConfig();
String parameter = mapping.getParameter();
if ("".equals(parameter)) {
parameter = null;
}
// Assign the default if the mapping did not provide a value
if (parameter == null) {
parameter = defaultMappingParameter;
}
// Parameter is required
if (parameter == null) {
String message = messages.getMessage(MSG_KEY_MISSING_MAPPING_PARAMETER, mapping.getPath());
log.error(message);
throw new IllegalStateException(message);
}
return parameter;
}
/**
* Stores the new default mapping parameter value.
*
* @param defaultMappingParameter the parameter value
* @see #getDefaultMappingParameter()
*/
protected final void setDefaultMappingParameter(String defaultMappingParameter) {
this.defaultMappingParameter = defaultMappingParameter;
}
}