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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.sample;
28  
29  import com.rapiddweller.benerator.GeneratorContext;
30  import com.rapiddweller.benerator.InvalidGeneratorSetupException;
31  import com.rapiddweller.benerator.util.ThreadSafeGenerator;
32  import com.rapiddweller.benerator.wrapper.ProductWrapper;
33  
34  /**
35   * Returns a value only once and then becomes unavailable immediately.<br/>
36   * <br/>
37   * Created at 23.09.2009 00:20:03
38   *
39   * @param <E> the type parameter
40   * @author Volker Bergmann
41   * @since 0.6.0
42   */
43  public class OneShotGenerator<E> extends ThreadSafeGenerator<E> {
44  
45    private E value;
46    private final Class<E> generatedType;
47    private boolean used;
48  
49    /**
50     * Instantiates a new One shot generator.
51     *
52     * @param value the value
53     */
54    @SuppressWarnings("unchecked")
55    public OneShotGenerator(E value) {
56      this(value, (Class<E>) value.getClass());
57    }
58  
59    /**
60     * Instantiates a new One shot generator.
61     *
62     * @param value         the value
63     * @param generatedType the generated type
64     */
65    public OneShotGenerator(E value, Class<E> generatedType) {
66      this.value = value;
67      this.generatedType = generatedType;
68      this.used = false;
69    }
70  
71    @Override
72    public void close() {
73      used = true;
74      value = null;
75      super.close();
76    }
77  
78    @Override
79    public ProductWrapper<E> generate(ProductWrapper<E> wrapper) {
80      if (used) {
81        return null;
82      }
83      used = true;
84      return wrapper.wrap(value);
85    }
86  
87    @Override
88    public Class<E> getGeneratedType() {
89      return generatedType;
90    }
91  
92    @Override
93    public void init(GeneratorContext context) throws InvalidGeneratorSetupException {
94      super.init(context);
95    }
96  
97    @Override
98    public void reset() {
99      used = false;
100     super.reset();
101   }
102 
103   @Override
104   public String toString() {
105     return getClass().getSimpleName() + '[' + value + ']';
106   }
107 
108 }