01: /*
02: * (c) Copyright 2006 by Volker Bergmann. All rights reserved.
03: *
04: * Redistribution and use in source and binary forms, with or without
05: * modification, is permitted under the terms of the
06: * GNU General Public License.
07: *
08: * For redistributing this software or a derivative work under a license other
09: * 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 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 org.databene.benerator.wrapper;
28:
29: import org.databene.benerator.Generator;
30: import org.databene.benerator.GeneratorProxy;
31:
32: import java.util.Random;
33:
34: /**
35: * Forwards the products from a source generator and injects a quota of null values.<br/>
36: * <br/>
37: * Created: 23.06.2006 20:01:07
38: */
39: public class NullableGenerator<E> extends GeneratorProxy<E> {
40:
41: /** the quota of nulls to create, ranging from 0 to 1 */
42: private double nullQuota;
43:
44: /** Helper for random number creation */
45: private Random random;
46:
47: // constructors ----------------------------------------------------------------------------------------------------
48:
49: public NullableGenerator() {
50: this (null, 0);
51: }
52:
53: public NullableGenerator(Generator<E> realGenerator,
54: double nullQuota) {
55: super (realGenerator);
56: this .nullQuota = nullQuota;
57: this .random = new Random();
58: }
59:
60: // config properties -----------------------------------------------------------------------------------------------
61:
62: /**
63: * Returns the nullQuota.
64: * @see #nullQuota
65: */
66: public double getNullQuota() {
67: return nullQuota;
68: }
69:
70: /**
71: * Sets the null quota
72: * @param nullQuota sets the nullQuota
73: * @see #nullQuota
74: */
75: public void setNullQuota(double nullQuota) {
76: this .nullQuota = nullQuota;
77: }
78:
79: // generator interface ---------------------------------------------------------------------------------------------
80:
81: /**
82: * Forwards the generated values of the source generator,
83: * including a defined quota of null values.
84: */
85: public E generate() {
86: if (random.nextFloat() < nullQuota)
87: return null;
88: else
89: return source.generate();
90: }
91:
92: }
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