/*
* Copyright 2002-2013 the original author or authors.
*
* Licensed 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 org.springframework.batch.item;
import org.springframework.core.convert.converter.Converter;
import org.springframework.expression.Expression;
import org.springframework.expression.ExpressionParser;
import org.springframework.expression.spel.standard.SpelExpressionParser;
/**
* An implementation of {@link Converter} that uses SpEL to map a Value to a key
* @author David Turanski
* @since 2.2
*/
public class SpELItemKeyMapper<K,V> implements Converter<V,K> {
private final ExpressionParser parser = new SpelExpressionParser();
private final Expression parsedExpression;
public SpELItemKeyMapper(String keyExpression) {
parsedExpression = parser.parseExpression(keyExpression);
}
/* (non-Javadoc)
* @see org.springframework.batch.item.ItemKeyMapper#mapKey(java.lang.Object)
*/
@SuppressWarnings("unchecked")
@Override
public K convert(V item) {
return (K) parsedExpression.getValue(item);
}
}