Classes in this File | Line Coverage | Branch Coverage | Complexity | ||||
AbstractConversion |
|
| 2.0;2 |
1 | /* | |
2 | * Copyright 2004 The Apache Software Foundation | |
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.apache.commons.convert.conversion; | |
17 | ||
18 | import org.apache.commons.convert.Conversion; | |
19 | import org.apache.commons.convert.Converter; | |
20 | ||
21 | /** | |
22 | * Abstract base class for conversion objects that provides basic features. | |
23 | * <p> | |
24 | * Most Conversion implementations will extend this class. It provides convenient | |
25 | * implementations of the methods of the interface, and simplifies null-handling | |
26 | * in the subclass. | |
27 | * <p> | |
28 | * To implement a conversion from a single class, simply extend this class and | |
29 | * implement the {@link #convertValue(Object, Converter)} method. To implement a | |
30 | * conversion from a class and its subclasses, use {@link AbstractConversionFactory}. | |
31 | * | |
32 | * @author Stephen Colebourne | |
33 | * @version $Id: AbstractConversion.java 155441 2005-02-26 13:19:22Z dirkv $ | |
34 | * @since 1.0 | |
35 | */ | |
36 | public abstract class AbstractConversion implements Conversion { | |
37 | ||
38 | /** Useful constant for subclass constructors */ | |
39 | 0 | protected static final Class STRING_CLASS = String.class; |
40 | ||
41 | /** The type to convert from */ | |
42 | private final Class fromType; | |
43 | /** The type to convert to */ | |
44 | private final Class toType; | |
45 | ||
46 | /** | |
47 | * Constructor that stores the from and to types. | |
48 | * | |
49 | * @param fromType the type to convert from | |
50 | * @param toType the type to convert to | |
51 | */ | |
52 | protected AbstractConversion(Class fromType, Class toType) { | |
53 | 0 | super(); |
54 | 0 | this.fromType = fromType; |
55 | 0 | this.toType = toType; |
56 | 0 | } |
57 | ||
58 | //----------------------------------------------------------------------- | |
59 | /** | |
60 | * Converts an object from one type to another. | |
61 | * <p> | |
62 | * This implementation delegates to <code>convertValue</code> after handling null. | |
63 | * If the null-safe behaviour is undesired, override this method. | |
64 | * | |
65 | * @param value the input value to be converted, may be null | |
66 | * @param converter the converter being used, not null | |
67 | * @return the converted value | |
68 | * @throws Exception if conversion fails, use ConversionException if creating | |
69 | * a new exception, otherwise just allow exceptions to be thrown | |
70 | */ | |
71 | public Object convert(Object value, Converter converter) throws Exception { | |
72 | 0 | if (value == null) { |
73 | 0 | return null; |
74 | } | |
75 | 0 | return convertValue(value, converter); |
76 | } | |
77 | ||
78 | /** | |
79 | * Convert the specified non-null value to another type. | |
80 | * | |
81 | * @param value the input value to be converted, pre-checked to not be null | |
82 | * @param converter the converter being used, not null | |
83 | * @return the converted value | |
84 | * @throws Exception if conversion fails, use ConversionException if creating | |
85 | * a new exception, otherwise just allow exceptions to be thrown | |
86 | */ | |
87 | protected Object convertValue(Object value, Converter converter) throws Exception { | |
88 | 0 | throw new UnsupportedOperationException("Not implemented"); |
89 | } | |
90 | ||
91 | //----------------------------------------------------------------------- | |
92 | /** | |
93 | * The type to convert from. | |
94 | * | |
95 | * @return the Class object representing the class to convert to | |
96 | */ | |
97 | public Class getFromType() { | |
98 | 0 | return fromType; |
99 | } | |
100 | ||
101 | /** | |
102 | * The type to convert to. | |
103 | * | |
104 | * @return the Class object representing the class to convert from | |
105 | */ | |
106 | public Class getToType() { | |
107 | 0 | return toType; |
108 | } | |
109 | ||
110 | //----------------------------------------------------------------------- | |
111 | /** | |
112 | * Gets a suitable debugging string. | |
113 | * | |
114 | * @return a debugging string | |
115 | */ | |
116 | public String toString() { | |
117 | 0 | String from = convertClassToName(getFromType()); |
118 | 0 | String to = convertClassToName(getToType()); |
119 | 0 | return "Conversion[" + from + "->" + to + "]"; |
120 | } | |
121 | ||
122 | /** | |
123 | * Converts a class to a string name for debugging. | |
124 | * | |
125 | * @param cls the class to convert | |
126 | * @return the class name | |
127 | */ | |
128 | private String convertClassToName(Class cls) { | |
129 | 0 | if (cls == null) { |
130 | 0 | return "null"; |
131 | } | |
132 | 0 | String str = cls.getName(); |
133 | 0 | int pos = str.lastIndexOf('.'); |
134 | 0 | if (str.substring(0, pos).equals("java.lang")) { |
135 | 0 | str = str.substring(pos + 1); |
136 | } | |
137 | 0 | if (str.substring(0, pos).equals("java.util")) { |
138 | 0 | str = str.substring(pos + 1); |
139 | } | |
140 | 0 | return str; |
141 | } | |
142 | ||
143 | } |