1 | /* |
2 | * Copyright 2006-2007 the original author or authors. |
3 | * |
4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
5 | * you may not use this file except in compliance with the License. |
6 | * You may obtain a copy of the License at |
7 | * |
8 | * http://www.apache.org/licenses/LICENSE-2.0 |
9 | * |
10 | * Unless required by applicable law or agreed to in writing, software |
11 | * distributed under the License is distributed on an "AS IS" BASIS, |
12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
13 | * See the License for the specific language governing permissions and |
14 | * limitations under the License. |
15 | */ |
16 | package org.springframework.batch.item.file.transform; |
17 | |
18 | import org.springframework.batch.item.file.mapping.DefaultFieldSet; |
19 | import org.springframework.batch.item.file.mapping.FieldSet; |
20 | import org.springframework.batch.item.transform.ItemTransformer; |
21 | |
22 | /** |
23 | * An {@link ItemTransformer} that expects a String[] as input and delegates to |
24 | * a {@link LineAggregator}. |
25 | * |
26 | * @author Dave Syer |
27 | * |
28 | */ |
29 | public class LineAggregatorItemTransformer implements ItemTransformer { |
30 | |
31 | private LineAggregator aggregator = new DelimitedLineAggregator(); |
32 | |
33 | /** |
34 | * Public setter for the {@link LineAggregator}. |
35 | * @param aggregator the aggregator to set |
36 | */ |
37 | public void setAggregator(LineAggregator aggregator) { |
38 | this.aggregator = aggregator; |
39 | } |
40 | |
41 | /** |
42 | * Assume the item is an array of String (no check is made) and delegate to |
43 | * the aggregator. |
44 | * |
45 | * @see org.springframework.batch.item.transform.ItemTransformer#transform(java.lang.Object) |
46 | */ |
47 | public Object transform(Object item) throws Exception { |
48 | return aggregator.aggregate(createFieldSet(item)); |
49 | } |
50 | |
51 | /** |
52 | * Extension point for subclasses. The default implementation just attempts |
53 | * to cast the item to String[] and creates a {@link DefaultFieldSet} from |
54 | * it. |
55 | * |
56 | * @param item an object (in this implementation of type String[]). |
57 | * @return a {@link FieldSet} representing the item |
58 | * |
59 | * @throws ConversionException if the field set cannot be created |
60 | */ |
61 | protected FieldSet createFieldSet(Object item) throws ConversionException { |
62 | try { |
63 | return new DefaultFieldSet((String[]) item); |
64 | } |
65 | catch (ClassCastException e) { |
66 | throw new ConversionException( |
67 | "Item must be of type String[] for conversion to FieldSet. " + |
68 | "Consider overriding this method to specify a less generic algorithm."); |
69 | } |
70 | } |
71 | } |