/*
* Copyright 2002-2009 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.springframework.expression.spel.support;
import org.springframework.expression.TypeComparator;
import org.springframework.expression.spel.SpelEvaluationException;
import org.springframework.expression.spel.SpelMessage;
/**
* A simple basic TypeComparator implementation. It supports comparison of numbers and types implementing Comparable.
*
* @author Andy Clement
* @author Juergen Hoeller
* @since 3.0
*/
public class StandardTypeComparator implements TypeComparator {
@SuppressWarnings("unchecked")
public int compare(Object left, Object right) throws SpelEvaluationException {
// If one is null, check if the other is
if (left == null) {
return right == null ? 0 : 1;
} else if (right == null) {
return -1; // left cannot be null
}
// Basic number comparisons
if (left instanceof Number && right instanceof Number) {
Number leftNumber = (Number) left;
Number rightNumber = (Number) right;
if (leftNumber instanceof Double || rightNumber instanceof Double) {
double d1 = leftNumber.doubleValue();
double d2 = rightNumber.doubleValue();
return Double.compare(d1,d2);
} else if (leftNumber instanceof Float || rightNumber instanceof Float) {
float f1 = leftNumber.floatValue();
float f2 = rightNumber.floatValue();
return Float.compare(f1,f2);
} else if (leftNumber instanceof Long || rightNumber instanceof Long) {
Long l1 = leftNumber.longValue();
Long l2 = rightNumber.longValue();
return l1.compareTo(l2);
} else {
Integer i1 = leftNumber.intValue();
Integer i2 = rightNumber.intValue();
return i1.compareTo(i2);
}
}
try {
if (left instanceof Comparable) {
return ((Comparable) left).compareTo(right);
}
} catch (ClassCastException cce) {
throw new SpelEvaluationException(cce, SpelMessage.NOT_COMPARABLE, left.getClass(), right.getClass());
}
throw new SpelEvaluationException(SpelMessage.NOT_COMPARABLE, left.getClass(), right.getClass());
}
public boolean canCompare(Object left, Object right) {
if (left == null || right == null) {
return true;
}
if (left instanceof Number && right instanceof Number) {
return true;
}
if (left instanceof Comparable) {
return true;
}
return false;
}
}
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