| 1 | /* |
| 2 | * Copyright 2002-2013 the original author or authors. |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with |
| 5 | * the License. You may obtain a copy of the License at |
| 6 | * |
| 7 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 8 | * |
| 9 | * Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on |
| 10 | * an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the |
| 11 | * specific language governing permissions and limitations under the License. |
| 12 | */ |
| 13 | package org.springframework.batch.item; |
| 14 | |
| 15 | import org.springframework.core.convert.converter.Converter; |
| 16 | import org.springframework.expression.Expression; |
| 17 | import org.springframework.expression.ExpressionParser; |
| 18 | import org.springframework.expression.spel.standard.SpelExpressionParser; |
| 19 | |
| 20 | /** |
| 21 | * An implementation of {@link Converter} that uses SpEL to map a Value to a key |
| 22 | * @author David Turanski |
| 23 | * @since 2.2 |
| 24 | */ |
| 25 | public class SpELItemKeyMapper<K,V> implements Converter<V,K> { |
| 26 | private final ExpressionParser parser = new SpelExpressionParser(); |
| 27 | private final Expression parsedExpression; |
| 28 | |
| 29 | public SpELItemKeyMapper(String keyExpression) { |
| 30 | parsedExpression = parser.parseExpression(keyExpression); |
| 31 | } |
| 32 | /* (non-Javadoc) |
| 33 | * @see org.springframework.batch.item.ItemKeyMapper#mapKey(java.lang.Object) |
| 34 | */ |
| 35 | @SuppressWarnings("unchecked") |
| 36 | @Override |
| 37 | public K convert(V item) { |
| 38 | return (K) parsedExpression.getValue(item); |
| 39 | } |
| 40 | } |