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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 org.slf4j.Logger;
import java.lang.reflect.Method;
import java.util.Map;
/**
* GetExecutor that is smart about Maps. If it detects one, it does not
* use Reflection but a cast to access the getter.
*
* @author Henning P. Schmiedehausen
* @version $Id$
* @since 1.5
*/
public class MapGetExecutor
extends AbstractExecutor
{
private final String property;
private final boolean isAlive;
public MapGetExecutor(final Logger log, final Object object, final String property)
{
this.log = log;
this.property = property;
isAlive = discover(object);
}
@Override
public Method getMethod()
{
if (isAlive())
{
return MapGetMethod.instance();
}
return null;
}
@Override
public boolean isAlive()
{
return isAlive;
}
protected boolean discover (final Object object)
{
if (object instanceof Map)
{
if (property != null)
{
return true;
}
}
return false;
}
@Override
public Object execute(final Object o)
{
return ((Map) o).get(property);
}
private static final class MapGetMethod
{
private static final Method instance;
static
{
try
{
instance = Map.class.getMethod("get", Object.class);
}
catch (final NoSuchMethodException mapGetMethodMissingError)
{
throw new Error(mapGetMethodMissingError);
}
}
private MapGetMethod() { }
static Method instance()
{
return instance;
}
}
}