1 /*
2 * (c) Copyright 2006-2020 by rapiddweller GmbH & Volker Bergmann. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, is permitted under the terms of the
6 * GNU General Public License.
7 *
8 * For redistributing this software or a derivative work under a license other
9 * than the GPL-compatible Free Software License as defined by the Free
10 * Software Foundation or approved by OSI, you must first obtain a commercial
11 * license to this software product from rapiddweller GmbH & Volker Bergmann.
12 *
13 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
14 * WITHOUT A WARRANTY OF ANY KIND. ALL EXPRESS OR IMPLIED CONDITIONS,
15 * REPRESENTATIONS AND WARRANTIES, INCLUDING ANY IMPLIED WARRANTY OF
16 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT, ARE
17 * HEREBY EXCLUDED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
18 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
19 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
20 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
21 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
22 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
23 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
24 * POSSIBILITY OF SUCH DAMAGE.
25 */
26
27 package com.rapiddweller.benerator.wrapper;
28
29 import com.rapiddweller.benerator.GeneratorContext;
30 import com.rapiddweller.benerator.IllegalGeneratorStateException;
31 import com.rapiddweller.benerator.InvalidGeneratorSetupException;
32 import com.rapiddweller.benerator.util.AbstractGenerator;
33 import com.rapiddweller.common.IOUtil;
34 import com.rapiddweller.common.TypedIterable;
35
36 import java.io.Closeable;
37 import java.util.Iterator;
38
39 /**
40 * Iterates over Iterators that are provided by an {@link Iterable}.<br/>
41 * <br/>
42 * Created: 16.08.2007 07:09:57
43 *
44 * @param <E> the type parameter
45 * @author Volker Bergmann
46 */
47 public class IteratingGenerator<E> extends AbstractGenerator<E> {
48
49 private TypedIterable<E> iterable;
50 private Iterator<E> iterator;
51
52 // constructors ----------------------------------------------------------------------------------------------------
53
54 /**
55 * Instantiates a new Iterating generator.
56 */
57 public IteratingGenerator() {
58 this(null);
59 }
60
61 /**
62 * Instantiates a new Iterating generator.
63 *
64 * @param iterable the iterable
65 */
66 public IteratingGenerator(TypedIterable<E> iterable) {
67 this.iterable = iterable;
68 this.iterator = null;
69 }
70
71 // properties ------------------------------------------------------------------------------------------------------
72
73 /**
74 * Gets iterable.
75 *
76 * @return the iterable
77 */
78 public TypedIterable<E> getIterable() {
79 return iterable;
80 }
81
82 /**
83 * Sets iterable.
84 *
85 * @param iterable the iterable
86 */
87 public void setIterable(TypedIterable<E> iterable) {
88 if (this.iterable != null) {
89 throw new IllegalGeneratorStateException("Mutating an initialized generator");
90 }
91 this.iterable = iterable;
92 }
93
94 // Generator interface ---------------------------------------------------------------------------------------------
95
96 @Override
97 public boolean isParallelizable() {
98 return false;
99 }
100
101 @Override
102 public boolean isThreadSafe() {
103 return false;
104 }
105
106 @Override
107 public void init(GeneratorContext context) {
108 if (iterable == null) {
109 throw new InvalidGeneratorSetupException("iterable", "is null");
110 }
111 super.init(context);
112 }
113
114 @Override
115 public Class<E> getGeneratedType() {
116 return iterable.getType();
117 }
118
119 @Override
120 public ProductWrapper<E> generate(ProductWrapper<E> wrapper) {
121 try {
122 assertInitialized();
123 if (iterator != null && !iterator.hasNext()) {
124 return null;
125 }
126 if (iterator == null) {
127 // iterator is created lazily for avoiding script evaluation errors in init()
128 createIterator();
129 }
130 if (!iterator.hasNext()) {
131 closeIterator();
132 return null;
133 }
134 E result = iterator.next();
135 if (!iterator.hasNext()) {
136 closeIterator();
137 }
138 return wrapper.wrap(result);
139 } catch (Exception e) {
140 throw new IllegalGeneratorStateException("Generation failed: ", e);
141 }
142 }
143
144 @Override
145 public void reset() {
146 closeIterator();
147 super.reset();
148 createIterator();
149 }
150
151 @Override
152 public void close() {
153 closeIterator();
154 super.close();
155 if (iterable instanceof Closeable) {
156 IOUtil.close((Closeable) iterable);
157 }
158 }
159
160 // private helpers -------------------------------------------------------------------------------------------------
161
162 private void createIterator() {
163 iterator = iterable.iterator();
164 }
165
166 private void closeIterator() {
167 if (iterator != null) {
168 if (iterator instanceof Closeable) {
169 IOUtil.close((Closeable) iterator);
170 }
171 }
172 }
173
174 // java.lang.Object overrides --------------------------------------------------------------------------------------
175
176 @Override
177 public String toString() {
178 return getClass().getSimpleName() + "[" + iterable + ']';
179 }
180
181 }