com.opensymphony.xwork2.interceptor.PrepareInterceptor Maven / Gradle / Ivy
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* Licensed to the Apache Software Foundation (ASF) under one
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* 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 com.opensymphony.xwork2.interceptor;
import com.opensymphony.xwork2.ActionInvocation;
import com.opensymphony.xwork2.Preparable;
import org.apache.logging.log4j.Logger;
import org.apache.logging.log4j.LogManager;
import java.lang.reflect.InvocationTargetException;
/**
*
*
* This interceptor calls prepare() on actions which implement
* {@link Preparable}. This interceptor is very useful for any situation where
* you need to ensure some logic runs before the actual execute method runs.
*
*
* A typical use of this is to run some logic to load an object from the
* database so that when parameters are set they can be set on this object. For
* example, suppose you have a User object with two properties: id and
* name. Provided that the params interceptor is called twice (once
* before and once after this interceptor), you can load the User object using
* the id property, and then when the second params interceptor is called the
* parameter user.name will be set, as desired, on the actual object
* loaded from the database. See the example for more info.
*
*
* Note: Since XWork 2.0.2, this interceptor extends {@link MethodFilterInterceptor}, therefore being
* able to deal with excludeMethods / includeMethods parameters. See [Workflow Interceptor]
* (class {@link DefaultWorkflowInterceptor}) for documentation and examples on how to use this feature.
*
*
*
* Update: Added logic to execute a prepare{MethodName} and conditionally
* the a general prepare() Method, depending on the 'alwaysInvokePrepare' parameter/property
* which is by default true. This allows us to run some logic based on the method
* name we specify in the {@link com.opensymphony.xwork2.ActionProxy}. For example, you can specify a
* prepareInput() method that will be run before the invocation of the input method.
*
*
*
*
* Interceptor parameters:
*
*
*
*
*
* - alwaysInvokePrepare - Default to true. If true, prepare will always be invoked,
* otherwise it will not.
*
*
*
*
*
* Extending the interceptor:
*
*
*
* There are no known extension points to this interceptor.
*
*
*
* Example code:
*
*
*
* <!-- Calls the params interceptor twice, allowing you to
* pre-load data for the second time parameters are set -->
* <action name="someAction" class="com.examples.SomeAction">
* <interceptor-ref name="params"/>
* <interceptor-ref name="prepare"/>
* <interceptor-ref name="basicStack"/>
* <result name="success">good_result.ftl</result>
* </action>
*
*
*
* @author Jason Carreira
* @author Philip Luppens
* @author tm_jee
* @see com.opensymphony.xwork2.Preparable
*/
public class PrepareInterceptor extends MethodFilterInterceptor {
private static final long serialVersionUID = -5216969014510719786L;
private final static String PREPARE_PREFIX = "prepare";
private final static String ALT_PREPARE_PREFIX = "prepareDo";
private boolean alwaysInvokePrepare = true;
private boolean firstCallPrepareDo = false;
/**
* Sets if the prepare method should always be executed.
*
* Default is true.
*
*
* @param alwaysInvokePrepare if prepare should always be executed or not.
*/
public void setAlwaysInvokePrepare(String alwaysInvokePrepare) {
this.alwaysInvokePrepare = Boolean.parseBoolean(alwaysInvokePrepare);
}
/**
* Sets if the prepareDoXXX method should be called first
*
* Default is false for backward compatibility
*
* @param firstCallPrepareDo if prepareDoXXX should be called first
*/
public void setFirstCallPrepareDo(String firstCallPrepareDo) {
this.firstCallPrepareDo = Boolean.parseBoolean(firstCallPrepareDo);
}
@Override
public String doIntercept(ActionInvocation invocation) throws Exception {
Object action = invocation.getAction();
if (action instanceof Preparable) {
try {
String[] prefixes;
if (firstCallPrepareDo) {
prefixes = new String[] {ALT_PREPARE_PREFIX, PREPARE_PREFIX};
} else {
prefixes = new String[] {PREPARE_PREFIX, ALT_PREPARE_PREFIX};
}
PrefixMethodInvocationUtil.invokePrefixMethod(invocation, prefixes);
}
catch (InvocationTargetException e) {
/*
* The invoked method threw an exception and reflection wrapped it
* in an InvocationTargetException.
* If possible re-throw the original exception so that normal
* exception handling will take place.
*/
Throwable cause = e.getCause();
if (cause instanceof Exception) {
throw (Exception) cause;
} else if(cause instanceof Error) {
throw (Error) cause;
} else {
/*
* The cause is not an Exception or Error (must be Throwable) so
* just re-throw the wrapped exception.
*/
throw e;
}
}
if (alwaysInvokePrepare) {
((Preparable) action).prepare();
}
}
return invocation.invoke();
}
}