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 java.util.List; |
16 | |
17 | import org.springframework.beans.factory.InitializingBean; |
18 | import org.springframework.core.convert.converter.Converter; |
19 | import org.springframework.util.Assert; |
20 | |
21 | /** |
22 | * A base class to implement any {@link ItemWriter} that writes to a key value store |
23 | * using a {@link Converter} to derive a key from an item |
24 | * |
25 | * @author David Turanski |
26 | * @since 2.2 |
27 | * |
28 | */ |
29 | public abstract class KeyValueItemWriter<K, V> implements ItemWriter<V>, InitializingBean { |
30 | |
31 | protected Converter<V, K> itemKeyMapper; |
32 | protected boolean delete; |
33 | |
34 | /* (non-Javadoc) |
35 | * @see org.springframework.batch.item.ItemWriter#write(java.util.List) |
36 | */ |
37 | @Override |
38 | public void write(List<? extends V> items) throws Exception { |
39 | if (items == null) { |
40 | return; |
41 | } |
42 | for (V item : items) { |
43 | K key = itemKeyMapper.convert(item); |
44 | writeKeyValue(key, item); |
45 | } |
46 | } |
47 | |
48 | /** |
49 | * Subclasses implement this method to write each item to key value store |
50 | * @param key the key |
51 | * @param value the item |
52 | */ |
53 | protected abstract void writeKeyValue(K key, V value); |
54 | |
55 | /** |
56 | * afterPropertiesSet() hook |
57 | */ |
58 | protected abstract void init(); |
59 | |
60 | /** |
61 | * Set the {@link Converter} to use to derive the key from the item |
62 | * @param itemKeyMapper |
63 | */ |
64 | public void setItemKeyMapper(Converter<V, K> itemKeyMapper) { |
65 | this.itemKeyMapper = itemKeyMapper; |
66 | } |
67 | |
68 | /** |
69 | * Sets the delete flag to have the item writer perform deletes |
70 | * @param delete |
71 | */ |
72 | public void setDelete(boolean delete) { |
73 | this.delete = delete; |
74 | } |
75 | |
76 | /* (non-Javadoc) |
77 | * @see org.springframework.beans.factory.InitializingBean#afterPropertiesSet() |
78 | */ |
79 | @Override |
80 | public void afterPropertiesSet() throws Exception { |
81 | Assert.notNull(itemKeyMapper, "itemKeyMapper requires a Converter type."); |
82 | init(); |
83 | } |
84 | } |