package org.apache.velocity.runtime.parser.node;
/*
* 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.
*/
import java.lang.reflect.InvocationTargetException;
import org.apache.velocity.exception.VelocityException;
import org.apache.velocity.runtime.RuntimeLogger;
import org.apache.velocity.runtime.log.Log;
import org.apache.velocity.runtime.log.RuntimeLoggerLog;
import org.apache.velocity.util.introspection.Introspector;
/**
* Executor that simply tries to execute a get(key)
* operation. This will try to find a get(key) method
* for any type of object, not just objects that
* implement the Map interface as was previously
* the case.
*
* @author <a href="mailto:[email protected]">Jason van Zyl</a>
* @version $Id: GetExecutor.java 687177 2008-08-19 22:00:32Z nbubna $
*/
public class GetExecutor extends AbstractExecutor
{
private final Introspector introspector;
// This is still threadsafe because this object is only read except in the C'tor.
private Object [] params = {};
/**
* @param log
* @param introspector
* @param clazz
* @param property
* @since 1.5
*/
public GetExecutor(final Log log, final Introspector introspector,
final Class clazz, final String property)
{
this.log = log;
this.introspector = introspector;
// If you passed in null as property, we don't use the value
// for parameter lookup. Instead we just look for get() without
// any parameters.
//
// In any other case, the following condition will set up an array
// for looking up get(String) on the class.
if (property != null)
{
this.params = new Object[] { property };
}
discover(clazz);
}
/**
* @param rlog
* @param introspector
* @param clazz
* @param property
* @deprecated RuntimeLogger is deprecated. Use the other constructor.
*/
public GetExecutor(final RuntimeLogger rlog, final Introspector introspector,
final Class clazz, final String property)
{
this(new RuntimeLoggerLog(rlog), introspector, clazz, property);
}
/**
* @since 1.5
*/
protected void discover(final Class clazz)
{
try
{
setMethod(introspector.getMethod(clazz, "get", params));
}
/**
* pass through application level runtime exceptions
*/
catch( RuntimeException e )
{
throw e;
}
catch(Exception e)
{
String msg = "Exception while looking for get('" + params[0] + "') method";
log.error(msg, e);
throw new VelocityException(msg, e);
}
}
/**
* @see org.apache.velocity.runtime.parser.node.AbstractExecutor#execute(java.lang.Object)
*/
public Object execute(final Object o)
throws IllegalAccessException, InvocationTargetException
{
return isAlive() ? getMethod().invoke(o, params) : null;
}
}
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