1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17 package org.apache.commons.betwixt.io.read;
18
19 import java.util.ArrayList;
20 import java.util.Iterator;
21
22 /***
23 * <p>Chain implementation that's backed by a list.
24 * This is the default implementation used by Betwixt.
25 * </p><p>
26 * <strong>Note</strong> this implementation is <em>not</em>
27 * intended to allow multiple threads of execution to perform
28 * modification operations concurrently with traversal of the chain.
29 * Users who require this behaviour are advised to create their own implementation.
30 * </p>
31 *
32 * @author Robert Burrell Donkin
33 * @since 0.5
34 */
35 public class BeanCreationList extends BeanCreationChain {
36
37
38
39 /***
40 * Creates the default <code>BeanCreationChain</code> used when reading beans.
41 * @return a <code>BeanCreationList</code> with the default creators loader in order, not null
42 */
43 public static final BeanCreationList createStandardChain() {
44 BeanCreationList chain = new BeanCreationList();
45 chain.addBeanCreator( ChainedBeanCreatorFactory.createIDREFBeanCreator() );
46 chain.addBeanCreator( ChainedBeanCreatorFactory.createDerivedBeanCreator() );
47 chain.addBeanCreator( ChainedBeanCreatorFactory.createElementTypeBeanCreator() );
48 return chain;
49 }
50
51
52
53
54 /*** The list backing this chain */
55 private ArrayList beanCreators = new ArrayList();
56
57
58
59 /***
60 * Creates an Object based on the given element mapping and read context.
61 * Delegates to chain.
62 *
63 * @param elementMapping the element mapping details
64 * @param readContext create against this context
65 * @return the created bean, possibly null
66 */
67 public Object create( ElementMapping elementMapping, ReadContext readContext ) {
68 ChainWorker worker = new ChainWorker();
69 return worker.create( elementMapping, readContext );
70 }
71
72
73
74 /***
75 * Gets the number of BeanCreators in the wrapped chain.
76 * @return the number of <code>ChainedBeanCreator</code>'s in the current chain
77 */
78 public int getSize() {
79 return beanCreators.size();
80 }
81
82 /***
83 * Inserts a <code>BeanCreator</code> at the given position in the chain.
84 * Shifts the object currently in that position - and any subsequent elements -
85 * to the right.
86 *
87 * @param index index at which the creator should be inserted
88 * @param beanCreator the <code>BeanCreator</code> to be inserted, not null
89 * @throws IndexOutOfBoundsException if the index is out of the range
90 * <code>(index < 0 || index > getSize())
91 */
92 public void insertBeanCreator(
93 int index,
94 ChainedBeanCreator beanCreator )
95 throws IndexOutOfBoundsException {
96 beanCreators.add( index, beanCreator );
97 }
98
99 /***
100 * Adds a <code>BeanCreator</code> to the end of the chain.
101 * @param beanCreator the <code>BeanCreator</code> to be inserted, not null
102 */
103 public void addBeanCreator( ChainedBeanCreator beanCreator ) {
104 beanCreators.add( beanCreator );
105 }
106
107 /***
108 * Clears the creator chain.
109 */
110 public void clearBeanCreators() {
111 beanCreators.clear();
112 }
113
114 /*** Worker class walks a chain */
115 private class ChainWorker extends BeanCreationChain {
116 /*** Iterator for the creator list */
117 private Iterator iterator;
118 /*** Creates the iterator */
119 ChainWorker() {
120 iterator = beanCreators.iterator();
121 }
122
123 /***
124 * @see BeanCreationChain#create
125 */
126 public Object create( ElementMapping elementMapping, ReadContext readContext ) {
127 if ( iterator.hasNext() ) {
128 ChainedBeanCreator beanCreator = (ChainedBeanCreator) iterator.next();
129 return beanCreator.create( elementMapping, readContext, this );
130 }
131
132 return null;
133 }
134 }
135 }