001/* 002 * Copyright 2002-2018 the original author or authors. 003 * 004 * Licensed under the Apache License, Version 2.0 (the "License"); 005 * you may not use this file except in compliance with the License. 006 * You may obtain a copy of the License at 007 * 008 * https://www.apache.org/licenses/LICENSE-2.0 009 * 010 * Unless required by applicable law or agreed to in writing, software 011 * distributed under the License is distributed on an "AS IS" BASIS, 012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 013 * See the License for the specific language governing permissions and 014 * limitations under the License. 015 */ 016 017package org.springframework.expression; 018 019import org.springframework.core.convert.TypeDescriptor; 020import org.springframework.lang.Nullable; 021import org.springframework.util.ObjectUtils; 022 023/** 024 * Encapsulates an object and a {@link TypeDescriptor} that describes it. 025 * The type descriptor can contain generic declarations that would not 026 * be accessible through a simple {@code getClass()} call on the object. 027 * 028 * @author Andy Clement 029 * @author Juergen Hoeller 030 * @since 3.0 031 */ 032public class TypedValue { 033 034 /** 035 * {@link TypedValue} for {@code null}. 036 */ 037 public static final TypedValue NULL = new TypedValue(null); 038 039 040 @Nullable 041 private final Object value; 042 043 @Nullable 044 private TypeDescriptor typeDescriptor; 045 046 047 /** 048 * Create a {@link TypedValue} for a simple object. The {@link TypeDescriptor} 049 * is inferred from the object, so no generic declarations are preserved. 050 * @param value the object value 051 */ 052 public TypedValue(@Nullable Object value) { 053 this.value = value; 054 this.typeDescriptor = null; // initialized when/if requested 055 } 056 057 /** 058 * Create a {@link TypedValue} for a particular value with a particular 059 * {@link TypeDescriptor} which may contain additional generic declarations. 060 * @param value the object value 061 * @param typeDescriptor a type descriptor describing the type of the value 062 */ 063 public TypedValue(@Nullable Object value, @Nullable TypeDescriptor typeDescriptor) { 064 this.value = value; 065 this.typeDescriptor = typeDescriptor; 066 } 067 068 069 @Nullable 070 public Object getValue() { 071 return this.value; 072 } 073 074 @Nullable 075 public TypeDescriptor getTypeDescriptor() { 076 if (this.typeDescriptor == null && this.value != null) { 077 this.typeDescriptor = TypeDescriptor.forObject(this.value); 078 } 079 return this.typeDescriptor; 080 } 081 082 083 @Override 084 public boolean equals(@Nullable Object other) { 085 if (this == other) { 086 return true; 087 } 088 if (!(other instanceof TypedValue)) { 089 return false; 090 } 091 TypedValue otherTv = (TypedValue) other; 092 // Avoid TypeDescriptor initialization if not necessary 093 return (ObjectUtils.nullSafeEquals(this.value, otherTv.value) && 094 ((this.typeDescriptor == null && otherTv.typeDescriptor == null) || 095 ObjectUtils.nullSafeEquals(getTypeDescriptor(), otherTv.getTypeDescriptor()))); 096 } 097 098 @Override 099 public int hashCode() { 100 return ObjectUtils.nullSafeHashCode(this.value); 101 } 102 103 @Override 104 public String toString() { 105 return "TypedValue: '" + this.value + "' of [" + getTypeDescriptor() + "]"; 106 } 107 108}