001/* 002 * Copyright 2002-2019 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.spel.support; 018 019import java.math.BigDecimal; 020import java.math.BigInteger; 021 022import org.springframework.expression.TypeComparator; 023import org.springframework.expression.spel.SpelEvaluationException; 024import org.springframework.expression.spel.SpelMessage; 025import org.springframework.lang.Nullable; 026import org.springframework.util.NumberUtils; 027 028/** 029 * A basic {@link TypeComparator} implementation: supports comparison of 030 * {@link Number} types as well as types implementing {@link Comparable}. 031 * 032 * @author Andy Clement 033 * @author Juergen Hoeller 034 * @author Giovanni Dall'Oglio Risso 035 * @since 3.0 036 */ 037public class StandardTypeComparator implements TypeComparator { 038 039 @Override 040 public boolean canCompare(@Nullable Object left, @Nullable Object right) { 041 if (left == null || right == null) { 042 return true; 043 } 044 if (left instanceof Number && right instanceof Number) { 045 return true; 046 } 047 if (left instanceof Comparable) { 048 return true; 049 } 050 return false; 051 } 052 053 @Override 054 @SuppressWarnings("unchecked") 055 public int compare(@Nullable Object left, @Nullable Object right) throws SpelEvaluationException { 056 // If one is null, check if the other is 057 if (left == null) { 058 return (right == null ? 0 : -1); 059 } 060 else if (right == null) { 061 return 1; // left cannot be null at this point 062 } 063 064 // Basic number comparisons 065 if (left instanceof Number && right instanceof Number) { 066 Number leftNumber = (Number) left; 067 Number rightNumber = (Number) right; 068 069 if (leftNumber instanceof BigDecimal || rightNumber instanceof BigDecimal) { 070 BigDecimal leftBigDecimal = NumberUtils.convertNumberToTargetClass(leftNumber, BigDecimal.class); 071 BigDecimal rightBigDecimal = NumberUtils.convertNumberToTargetClass(rightNumber, BigDecimal.class); 072 return leftBigDecimal.compareTo(rightBigDecimal); 073 } 074 else if (leftNumber instanceof Double || rightNumber instanceof Double) { 075 return Double.compare(leftNumber.doubleValue(), rightNumber.doubleValue()); 076 } 077 else if (leftNumber instanceof Float || rightNumber instanceof Float) { 078 return Float.compare(leftNumber.floatValue(), rightNumber.floatValue()); 079 } 080 else if (leftNumber instanceof BigInteger || rightNumber instanceof BigInteger) { 081 BigInteger leftBigInteger = NumberUtils.convertNumberToTargetClass(leftNumber, BigInteger.class); 082 BigInteger rightBigInteger = NumberUtils.convertNumberToTargetClass(rightNumber, BigInteger.class); 083 return leftBigInteger.compareTo(rightBigInteger); 084 } 085 else if (leftNumber instanceof Long || rightNumber instanceof Long) { 086 return Long.compare(leftNumber.longValue(), rightNumber.longValue()); 087 } 088 else if (leftNumber instanceof Integer || rightNumber instanceof Integer) { 089 return Integer.compare(leftNumber.intValue(), rightNumber.intValue()); 090 } 091 else if (leftNumber instanceof Short || rightNumber instanceof Short) { 092 return Short.compare(leftNumber.shortValue(), rightNumber.shortValue()); 093 } 094 else if (leftNumber instanceof Byte || rightNumber instanceof Byte) { 095 return Byte.compare(leftNumber.byteValue(), rightNumber.byteValue()); 096 } 097 else { 098 // Unknown Number subtypes -> best guess is double multiplication 099 return Double.compare(leftNumber.doubleValue(), rightNumber.doubleValue()); 100 } 101 } 102 103 try { 104 if (left instanceof Comparable) { 105 return ((Comparable<Object>) left).compareTo(right); 106 } 107 } 108 catch (ClassCastException ex) { 109 throw new SpelEvaluationException(ex, SpelMessage.NOT_COMPARABLE, left.getClass(), right.getClass()); 110 } 111 112 throw new SpelEvaluationException(SpelMessage.NOT_COMPARABLE, left.getClass(), right.getClass()); 113 } 114 115}