/*
 * 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
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package org.springframework.expression.spel.ast;

import java.math.BigDecimal;
import java.math.BigInteger;

import org.springframework.asm.MethodVisitor;
import org.springframework.expression.EvaluationException;
import org.springframework.expression.Operation;
import org.springframework.expression.TypedValue;
import org.springframework.expression.spel.CodeFlow;
import org.springframework.expression.spel.ExpressionState;
import org.springframework.util.Assert;
import org.springframework.util.NumberUtils;

The minus operator supports:
  • subtraction of numbers
  • subtraction of an int from a string of one character (effectively decreasing that character), so 'd'-3='a'

It can be used as a unary operator for numbers. 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, Juergen Hoeller, Giovanni Dall'Oglio Risso
Since:3.0
/** * The minus operator supports: * <ul> * <li>subtraction of numbers * <li>subtraction of an int from a string of one character * (effectively decreasing that character), so 'd'-3='a' * </ul> * * <p>It can be used as a unary operator for numbers. * 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 * @author Juergen Hoeller * @author Giovanni Dall'Oglio Risso * @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(); if (this.children.length < 2) { // if only one operand, then this is unary minus Object operand = leftOp.getValueInternal(state).getValue(); if (operand instanceof Number) { if (operand instanceof BigDecimal) { return new TypedValue(((BigDecimal) operand).negate()); } else if (operand instanceof Double) { this.exitTypeDescriptor = "D"; return new TypedValue(0 - ((Number) operand).doubleValue()); } else if (operand instanceof Float) { this.exitTypeDescriptor = "F"; return new TypedValue(0 - ((Number) operand).floatValue()); } else if (operand instanceof BigInteger) { return new TypedValue(((BigInteger) operand).negate()); } else if (operand instanceof Long) { this.exitTypeDescriptor = "J"; return new TypedValue(0 - ((Number) operand).longValue()); } else if (operand instanceof Integer) { this.exitTypeDescriptor = "I"; return new TypedValue(0 - ((Number) operand).intValue()); } else if (operand instanceof Short) { return new TypedValue(0 - ((Number) operand).shortValue()); } else if (operand instanceof Byte) { return new TypedValue(0 - ((Number) operand).byteValue()); } else { // Unknown Number subtypes -> best guess is double subtraction return new TypedValue(0 - ((Number) operand).doubleValue()); } } return state.operate(Operation.SUBTRACT, operand, null); } Object left = leftOp.getValueInternal(state).getValue(); Object right = getRightOperand().getValueInternal(state).getValue(); if (left instanceof Number && right instanceof Number) { Number leftNumber = (Number) left; Number rightNumber = (Number) right; if (leftNumber instanceof BigDecimal || rightNumber instanceof BigDecimal) { BigDecimal leftBigDecimal = NumberUtils.convertNumberToTargetClass(leftNumber, BigDecimal.class); BigDecimal rightBigDecimal = NumberUtils.convertNumberToTargetClass(rightNumber, BigDecimal.class); return new TypedValue(leftBigDecimal.subtract(rightBigDecimal)); } else if (leftNumber instanceof Double || rightNumber instanceof Double) { this.exitTypeDescriptor = "D"; return new TypedValue(leftNumber.doubleValue() - rightNumber.doubleValue()); } else if (leftNumber instanceof Float || rightNumber instanceof Float) { this.exitTypeDescriptor = "F"; return new TypedValue(leftNumber.floatValue() - rightNumber.floatValue()); } else if (leftNumber instanceof BigInteger || rightNumber instanceof BigInteger) { BigInteger leftBigInteger = NumberUtils.convertNumberToTargetClass(leftNumber, BigInteger.class); BigInteger rightBigInteger = NumberUtils.convertNumberToTargetClass(rightNumber, BigInteger.class); return new TypedValue(leftBigInteger.subtract(rightBigInteger)); } else if (leftNumber instanceof Long || rightNumber instanceof Long) { this.exitTypeDescriptor = "J"; return new TypedValue(leftNumber.longValue() - rightNumber.longValue()); } else if (CodeFlow.isIntegerForNumericOp(leftNumber) || CodeFlow.isIntegerForNumericOp(rightNumber)) { this.exitTypeDescriptor = "I"; return new TypedValue(leftNumber.intValue() - rightNumber.intValue()); } else { // Unknown Number subtypes -> best guess is double subtraction return new TypedValue(leftNumber.doubleValue() - rightNumber.doubleValue()); } } 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 (this.children.length < 2) { // unary minus return "-" + getLeftOperand().toStringAST(); } return super.toStringAST(); } @Override public SpelNodeImpl getRightOperand() { if (this.children.length < 2) { throw new IllegalStateException("No right operand"); } return this.children[1]; } @Override public boolean isCompilable() { if (!getLeftOperand().isCompilable()) { return false; } if (this.children.length > 1) { if (!getRightOperand().isCompilable()) { return false; } } return (this.exitTypeDescriptor != null); } @Override public void generateCode(MethodVisitor mv, CodeFlow cf) { getLeftOperand().generateCode(mv, cf); String leftDesc = getLeftOperand().exitTypeDescriptor; String exitDesc = this.exitTypeDescriptor; Assert.state(exitDesc != null, "No exit type descriptor"); char targetDesc = exitDesc.charAt(0); CodeFlow.insertNumericUnboxOrPrimitiveTypeCoercion(mv, leftDesc, targetDesc); if (this.children.length > 1) { cf.enterCompilationScope(); getRightOperand().generateCode(mv, cf); String rightDesc = getRightOperand().exitTypeDescriptor; cf.exitCompilationScope(); CodeFlow.insertNumericUnboxOrPrimitiveTypeCoercion(mv, rightDesc, targetDesc); switch (targetDesc) { case 'I': mv.visitInsn(ISUB); break; case 'J': mv.visitInsn(LSUB); break; case 'F': mv.visitInsn(FSUB); break; case 'D': mv.visitInsn(DSUB); break; default: throw new IllegalStateException( "Unrecognized exit type descriptor: '" + this.exitTypeDescriptor + "'"); } } else { switch (targetDesc) { case 'I': mv.visitInsn(INEG); break; case 'J': mv.visitInsn(LNEG); break; case 'F': mv.visitInsn(FNEG); break; case 'D': mv.visitInsn(DNEG); break; default: throw new IllegalStateException( "Unrecognized exit type descriptor: '" + this.exitTypeDescriptor + "'"); } } cf.pushDescriptor(this.exitTypeDescriptor); } }