1 /*
2 * Copyright 2002-2014 the original author or authors.
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
17 package org.springframework.expression;
18
19 import org.springframework.core.convert.TypeDescriptor;
20 import org.springframework.util.ObjectUtils;
21
22 /**
23 * Encapsulates an object and a {@link TypeDescriptor} that describes it.
24 * The type descriptor can contain generic declarations that would not
25 * be accessible through a simple {@code getClass()} call on the object.
26 *
27 * @author Andy Clement
28 * @author Juergen Hoeller
29 * @since 3.0
30 */
31 public class TypedValue {
32
33 public static final TypedValue NULL = new TypedValue(null);
34
35
36 private final Object value;
37
38 private TypeDescriptor typeDescriptor;
39
40
41 /**
42 * Create a {@link TypedValue} for a simple object. The {@link TypeDescriptor}
43 * is inferred from the object, so no generic declarations are preserved.
44 * @param value the object value
45 */
46 public TypedValue(Object value) {
47 this.value = value;
48 this.typeDescriptor = null; // initialized when/if requested
49 }
50
51 /**
52 * Create a {@link TypedValue} for a particular value with a particular
53 * {@link TypeDescriptor} which may contain additional generic declarations.
54 * @param value the object value
55 * @param typeDescriptor a type descriptor describing the type of the value
56 */
57 public TypedValue(Object value, TypeDescriptor typeDescriptor) {
58 this.value = value;
59 this.typeDescriptor = typeDescriptor;
60 }
61
62
63 public Object getValue() {
64 return this.value;
65 }
66
67 public TypeDescriptor getTypeDescriptor() {
68 if (this.typeDescriptor == null && this.value != null) {
69 this.typeDescriptor = TypeDescriptor.forObject(this.value);
70 }
71 return this.typeDescriptor;
72 }
73
74
75 @Override
76 public boolean equals(Object other) {
77 if (this == other) {
78 return true;
79 }
80 if (!(other instanceof TypedValue)) {
81 return false;
82 }
83 TypedValue otherTv = (TypedValue) other;
84 // Avoid TypeDescriptor initialization if not necessary
85 return (ObjectUtils.nullSafeEquals(this.value, otherTv.value) &&
86 ((this.typeDescriptor == null && otherTv.typeDescriptor == null) ||
87 ObjectUtils.nullSafeEquals(getTypeDescriptor(), otherTv.getTypeDescriptor())));
88 }
89
90 @Override
91 public int hashCode() {
92 return ObjectUtils.nullSafeHashCode(this.value);
93 }
94
95 @Override
96 public String toString() {
97 return "TypedValue: '" + this.value + "' of [" + getTypeDescriptor() + "]";
98 }
99
100 }