/*
 * Copyright 2002-2019 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
 *
 *      https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
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 * See the License for the specific language governing permissions and
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package org.springframework.expression.spel.ast;

import org.springframework.asm.Label;
import org.springframework.asm.MethodVisitor;
import org.springframework.expression.EvaluationContext;
import org.springframework.expression.EvaluationException;
import org.springframework.expression.spel.CodeFlow;
import org.springframework.expression.spel.ExpressionState;
import org.springframework.expression.spel.support.BooleanTypedValue;

Implements the not-equal operator.
Author:Andy Clement
Since:3.0
/** * Implements the not-equal operator. * * @author Andy Clement * @since 3.0 */
public class OpNE extends Operator { public OpNE(int startPos, int endPos, SpelNodeImpl... operands) { super("!=", startPos, endPos, operands); this.exitTypeDescriptor = "Z"; } @Override public BooleanTypedValue getValueInternal(ExpressionState state) throws EvaluationException { Object leftValue = getLeftOperand().getValueInternal(state).getValue(); Object rightValue = getRightOperand().getValueInternal(state).getValue(); this.leftActualDescriptor = CodeFlow.toDescriptorFromObject(leftValue); this.rightActualDescriptor = CodeFlow.toDescriptorFromObject(rightValue); return BooleanTypedValue.forValue(!equalityCheck(state.getEvaluationContext(), leftValue, rightValue)); } // This check is different to the one in the other numeric operators (OpLt/etc) // because we allow simple object comparison @Override public boolean isCompilable() { SpelNodeImpl left = getLeftOperand(); SpelNodeImpl right = getRightOperand(); if (!left.isCompilable() || !right.isCompilable()) { return false; } String leftDesc = left.exitTypeDescriptor; String rightDesc = right.exitTypeDescriptor; DescriptorComparison dc = DescriptorComparison.checkNumericCompatibility(leftDesc, rightDesc, this.leftActualDescriptor, this.rightActualDescriptor); return (!dc.areNumbers || dc.areCompatible); } @Override public void generateCode(MethodVisitor mv, CodeFlow cf) { cf.loadEvaluationContext(mv); String leftDesc = getLeftOperand().exitTypeDescriptor; String rightDesc = getRightOperand().exitTypeDescriptor; boolean leftPrim = CodeFlow.isPrimitive(leftDesc); boolean rightPrim = CodeFlow.isPrimitive(rightDesc); cf.enterCompilationScope(); getLeftOperand().generateCode(mv, cf); cf.exitCompilationScope(); if (leftPrim) { CodeFlow.insertBoxIfNecessary(mv, leftDesc.charAt(0)); } cf.enterCompilationScope(); getRightOperand().generateCode(mv, cf); cf.exitCompilationScope(); if (rightPrim) { CodeFlow.insertBoxIfNecessary(mv, rightDesc.charAt(0)); } String operatorClassName = Operator.class.getName().replace('.', '/'); String evaluationContextClassName = EvaluationContext.class.getName().replace('.', '/'); mv.visitMethodInsn(INVOKESTATIC, operatorClassName, "equalityCheck", "(L" + evaluationContextClassName + ";Ljava/lang/Object;Ljava/lang/Object;)Z", false); // Invert the boolean Label notZero = new Label(); Label end = new Label(); mv.visitJumpInsn(IFNE, notZero); mv.visitInsn(ICONST_1); mv.visitJumpInsn(GOTO, end); mv.visitLabel(notZero); mv.visitInsn(ICONST_0); mv.visitLabel(end); cf.pushDescriptor("Z"); } }