/*
* 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.ast;
import org.springframework.expression.EvaluationException;
import org.springframework.expression.Operation;
import org.springframework.expression.TypedValue;
import org.springframework.expression.spel.ExpressionState;
/**
* The minus operator supports:
* <ul>
* <li>subtraction of doubles (floats are represented as doubles)
* <li>subtraction of longs
* <li>subtraction of integers
* <li>subtraction of an int from a string of one character (effectively decreasing that character), so 'd'-3='a'
* </ul>
* It can be used as a unary operator for numbers (double/long/int). The standard promotions are performed
* when the operand types vary (double-int=double).
* For other options it defers to the registered overloader.
*
* @author Andy Clement
* @since 3.0
*/
public class OpMinus extends Operator {
public OpMinus(int pos, SpelNodeImpl... operands) {
super("-", pos, operands);
}
@Override
public TypedValue getValueInternal(ExpressionState state) throws EvaluationException {
SpelNodeImpl leftOp = getLeftOperand();
SpelNodeImpl rightOp = getRightOperand();
if (rightOp == null) {// If only one operand, then this is unary minus
Object operand = leftOp.getValueInternal(state).getValue();
if (operand instanceof Number) {
Number n = (Number) operand;
if (operand instanceof Double) {
return new TypedValue(0 - n.doubleValue());
} else if (operand instanceof Long) {
return new TypedValue(0 - n.longValue());
} else {
return new TypedValue(0 - n.intValue());
}
}
return state.operate(Operation.SUBTRACT, operand, null);
} else {
Object left = leftOp.getValueInternal(state).getValue();
Object right = rightOp.getValueInternal(state).getValue();
if (left instanceof Number && right instanceof Number) {
Number op1 = (Number) left;
Number op2 = (Number) right;
if (op1 instanceof Double || op2 instanceof Double) {
return new TypedValue(op1.doubleValue() - op2.doubleValue());
} else if (op1 instanceof Long || op2 instanceof Long) {
return new TypedValue(op1.longValue() - op2.longValue());
} else {
return new TypedValue(op1.intValue() - op2.intValue());
}
} else if (left instanceof String && right instanceof Integer && ((String)left).length()==1) {
String theString = (String) left;
Integer theInteger = (Integer) right;
// implements character - int (ie. b - 1 = a)
return new TypedValue(Character.toString((char) (theString.charAt(0) - theInteger)));
}
return state.operate(Operation.SUBTRACT, left, right);
}
}
@Override
public String toStringAST() {
if (getRightOperand() == null) { // unary minus
return new StringBuilder().append("-").append(getLeftOperand().toStringAST()).toString();
}
return super.toStringAST();
}
public SpelNodeImpl getRightOperand() {
if (children.length<2) {return null;}
return children[1];
}
}
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