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Spring Expression Language (SpEL)
/*
* Copyright 2002-2014 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.asm.Label;
import org.springframework.asm.MethodVisitor;
import org.springframework.expression.EvaluationException;
import org.springframework.expression.spel.CodeFlow;
import org.springframework.expression.spel.ExpressionState;
import org.springframework.expression.spel.SpelEvaluationException;
import org.springframework.expression.spel.SpelMessage;
import org.springframework.expression.spel.support.BooleanTypedValue;
/**
* Represents the boolean OR operation.
*
* @author Andy Clement
* @author Mark Fisher
* @author Oliver Becker
* @since 3.0
*/
public class OpOr extends Operator {
public OpOr(int pos, SpelNodeImpl... operands) {
super("or", pos, operands);
this.exitTypeDescriptor = "Z";
}
@Override
public BooleanTypedValue getValueInternal(ExpressionState state) throws EvaluationException {
if (getBooleanValue(state, getLeftOperand())) {
// no need to evaluate right operand
return BooleanTypedValue.TRUE;
}
return BooleanTypedValue.forValue(getBooleanValue(state, getRightOperand()));
}
private boolean getBooleanValue(ExpressionState state, SpelNodeImpl operand) {
try {
Boolean value = operand.getValue(state, Boolean.class);
assertValueNotNull(value);
return value;
}
catch (SpelEvaluationException ee) {
ee.setPosition(operand.getStartPosition());
throw ee;
}
}
private void assertValueNotNull(Boolean value) {
if (value == null) {
throw new SpelEvaluationException(SpelMessage.TYPE_CONVERSION_ERROR, "null", "boolean");
}
}
@Override
public boolean isCompilable() {
SpelNodeImpl left = getLeftOperand();
SpelNodeImpl right = getRightOperand();
return (left.isCompilable() && right.isCompilable() &&
CodeFlow.isBooleanCompatible(left.exitTypeDescriptor) &&
CodeFlow.isBooleanCompatible(right.exitTypeDescriptor));
}
@Override
public void generateCode(MethodVisitor mv, CodeFlow cf) {
// pseudo: if (leftOperandValue) { result=true; } else { result=rightOperandValue; }
Label elseTarget = new Label();
Label endOfIf = new Label();
cf.enterCompilationScope();
getLeftOperand().generateCode(mv, cf);
cf.unboxBooleanIfNecessary(mv);
cf.exitCompilationScope();
mv.visitJumpInsn(IFEQ, elseTarget);
mv.visitLdcInsn(1); // TRUE
mv.visitJumpInsn(GOTO,endOfIf);
mv.visitLabel(elseTarget);
cf.enterCompilationScope();
getRightOperand().generateCode(mv, cf);
cf.unboxBooleanIfNecessary(mv);
cf.exitCompilationScope();
mv.visitLabel(endOfIf);
cf.pushDescriptor(this.exitTypeDescriptor);
}
}