org.apache.struts.dispatcher.AbstractEventMappingDispatcher Maven / Gradle / Ivy
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* to you under the Apache License, Version 2.0 (the
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* http://www.apache.org/licenses/LICENSE-2.0
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package org.apache.struts.dispatcher;
import org.apache.struts.action.ActionMapping;
import org.apache.struts.chain.contexts.ActionContext;
import java.util.StringTokenizer;
/**
* This abstract class is a template for choosing the target method that is
* named in the list-encoded parameter attribute of the
* {@link ActionMapping} that matches a submission parameter. This is useful for
* developers who prefer to use many submit buttons, images, or submit links on
* a single form and whose related actions exist in a single action.
*
* For utility purposes, you can use the key=value notation to
* alias methods so that they are exposed as different form element names, in
* the event of a naming conflict or otherwise. In this example, the
* recalc button (via a submission parameter) will invoke the
* recalculate method. The security-minded person may find this
* feature valuable to obfuscate and not expose the methods.
*
* The default key is purely optional, but encouraged when nothing
* matches (such as the user pressing the enter key). If this is not specified
* and no parameters match the list of method keys, the method resolution
* returns null.
*
* The order of the parameters are guaranteed to be iterated in the order
* specified. If multiple buttons were accidently submitted, the first match in
* the list will be dispatched.
*
* @version $Rev$
* @since Struts 1.4
*/
public abstract class AbstractEventMappingDispatcher extends AbstractMappingDispatcher {
/**
* The method key, if present, to use if other specified method keys do not
* match a request parameter.
*/
protected static final String DEFAULT_METHOD_KEY = "default";
/**
* Constructs a new dispatcher with the specified method resolver.
*
* @param methodResolver the method resolver
*/
public AbstractEventMappingDispatcher(MethodResolver methodResolver) {
super(methodResolver);
}
/**
* Determines whether the specified method key is a submission parameter.
*
* @param context the current action context
* @param methodKey the method key
* @return true if match; otherwise false
* @see #resolveMethodName(ActionContext)
*/
protected abstract boolean isSubmissionParameter(ActionContext context, String methodKey);
protected final String resolveMethodName(ActionContext context) {
// Obtain the mapping parameter
String mappingParameter = super.resolveMethodName(context);
if (mappingParameter == null) {
return null;
}
// Parse it as a comma-separated list
StringTokenizer st = new StringTokenizer(mappingParameter, ",");
String defaultMethodName = null;
while (st.hasMoreTokens()) {
String methodKey = st.nextToken().trim();
String methodName = methodKey;
// The key can either be a direct method name or an alias
// to a method as indicated by a "key=value" signature
int equals = methodKey.indexOf('=');
if (equals > -1) {
methodName = methodKey.substring(equals + 1).trim();
methodKey = methodKey.substring(0, equals).trim();
}
// Set the default if it passes by
if (methodKey.equals(DEFAULT_METHOD_KEY)) {
defaultMethodName = methodName;
}
// Is it a match?
if (isSubmissionParameter(context, methodKey)) {
return methodName;
}
}
return defaultMethodName;
}
}