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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.apache.commons.lang3.StringUtils;
import org.apache.velocity.exception.VelocityException;
import org.apache.velocity.util.introspection.Introspector;
import org.slf4j.Logger;
import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
/**
* Returns the value of a public field when executed.
*/
public class PublicFieldExecutor extends AbstractExecutor
{
private final Introspector introspector;
/**
* Field to be accessed
*/
private Field field = null;
/**
* @param log
* @param introspector
* @param clazz
* @param property
* @since 1.5
*/
public PublicFieldExecutor(final Logger log, final Introspector introspector,
final Class clazz, final String property)
{
this.log = log;
this.introspector = introspector;
// Don't allow passing in the empty string or null because
// it will either fail with a StringIndexOutOfBounds error
// or the introspector will get confused.
if (StringUtils.isNotEmpty(property))
{
discover(clazz, property);
}
}
@Override
public boolean isAlive() {
return getField() != null;
}
/**
* @return The current field.
*/
public Field getField()
{
return field;
}
/**
* @param field
*/
protected void setField(final Field field)
{
this.field = field;
}
/**
* @return The current introspector.
* @since 1.5
*/
protected Introspector getIntrospector()
{
return this.introspector;
}
/**
* @param clazz
* @param property
*/
protected void discover(final Class clazz, final String property)
{
try
{
setField(introspector.getField(clazz, property));
}
/*
* pass through application level runtime exceptions
*/
catch( RuntimeException e )
{
throw e;
}
catch(Exception e)
{
String msg = "Exception while looking for public field '" + property;
log.error(msg, e);
throw new VelocityException(msg, e);
}
}
/**
* @see org.apache.velocity.runtime.parser.node.AbstractExecutor#execute(java.lang.Object)
*/
@Override
public Object execute(Object o)
throws IllegalAccessException, InvocationTargetException
{
return isAlive() ? getField().get(o) : null;
}
}