/*
* Copyright 2002-2017 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 java.math.BigDecimal;
import java.math.BigInteger;
import org.springframework.expression.EvaluationException;
import org.springframework.expression.Operation;
import org.springframework.expression.TypedValue;
import org.springframework.expression.spel.ExpressionState;
import org.springframework.expression.spel.SpelEvaluationException;
import org.springframework.expression.spel.SpelMessage;
import org.springframework.util.Assert;
/**
* Decrement operator. Can be used in a prefix or postfix form. This will throw
* appropriate exceptions if the operand in question does not support decrement.
*
* @author Andy Clement
* @author Juergen Hoeller
* @author Giovanni Dall'Oglio Risso
* @since 3.2
*/
public class OpDec extends Operator {
private final boolean postfix; // false means prefix
public OpDec(int pos, boolean postfix, SpelNodeImpl... operands) {
super("--", pos, operands);
this.postfix = postfix;
Assert.notEmpty(operands, "Operands must not be empty");
}
@Override
public TypedValue getValueInternal(ExpressionState state) throws EvaluationException {
SpelNodeImpl operand = getLeftOperand();
// The operand is going to be read and then assigned to, we don't want to evaluate it twice.
ValueRef lvalue = operand.getValueRef(state);
TypedValue operandTypedValue = lvalue.getValue(); //operand.getValueInternal(state);
Object operandValue = operandTypedValue.getValue();
TypedValue returnValue = operandTypedValue;
TypedValue newValue = null;
if (operandValue instanceof Number) {
Number op1 = (Number) operandValue;
if (op1 instanceof BigDecimal) {
newValue = new TypedValue(((BigDecimal) op1).subtract(BigDecimal.ONE), operandTypedValue.getTypeDescriptor());
}
else if (op1 instanceof Double) {
newValue = new TypedValue(op1.doubleValue() - 1.0d, operandTypedValue.getTypeDescriptor());
}
else if (op1 instanceof Float) {
newValue = new TypedValue(op1.floatValue() - 1.0f, operandTypedValue.getTypeDescriptor());
}
else if (op1 instanceof BigInteger) {
newValue = new TypedValue(((BigInteger) op1).subtract(BigInteger.ONE), operandTypedValue.getTypeDescriptor());
}
else if (op1 instanceof Long) {
newValue = new TypedValue(op1.longValue() - 1L, operandTypedValue.getTypeDescriptor());
}
else if (op1 instanceof Integer) {
newValue = new TypedValue(op1.intValue() - 1, operandTypedValue.getTypeDescriptor());
}
else if (op1 instanceof Short) {
newValue = new TypedValue(op1.shortValue() - (short) 1, operandTypedValue.getTypeDescriptor());
}
else if (op1 instanceof Byte) {
newValue = new TypedValue(op1.byteValue() - (byte) 1, operandTypedValue.getTypeDescriptor());
}
else {
// Unknown Number subtype -> best guess is double decrement
newValue = new TypedValue(op1.doubleValue() - 1.0d, operandTypedValue.getTypeDescriptor());
}
}
if (newValue == null) {
try {
newValue = state.operate(Operation.SUBTRACT, returnValue.getValue(), 1);
}
catch (SpelEvaluationException ex) {
if (ex.getMessageCode() == SpelMessage.OPERATOR_NOT_SUPPORTED_BETWEEN_TYPES) {
// This means the operand is not decrementable
throw new SpelEvaluationException(operand.getStartPosition(),
SpelMessage.OPERAND_NOT_DECREMENTABLE, operand.toStringAST());
}
else {
throw ex;
}
}
}
// set the new value
try {
lvalue.setValue(newValue.getValue());
}
catch (SpelEvaluationException see) {
// if unable to set the value the operand is not writable (e.g. 1-- )
if (see.getMessageCode() == SpelMessage.SETVALUE_NOT_SUPPORTED) {
throw new SpelEvaluationException(operand.getStartPosition(),
SpelMessage.OPERAND_NOT_DECREMENTABLE);
}
else {
throw see;
}
}
if (!this.postfix) {
// the return value is the new value, not the original value
returnValue = newValue;
}
return returnValue;
}
@Override
public String toStringAST() {
return getLeftOperand().toStringAST() + "--";
}
@Override
public SpelNodeImpl getRightOperand() {
return null;
}
}