001/*
002 * Copyright 2002-2015 the original author or authors.
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 *      https://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016
017package org.springframework.expression.spel.ast;
018
019import java.math.BigDecimal;
020import java.math.BigInteger;
021
022import org.springframework.asm.MethodVisitor;
023import org.springframework.expression.EvaluationException;
024import org.springframework.expression.Operation;
025import org.springframework.expression.TypedValue;
026import org.springframework.expression.spel.CodeFlow;
027import org.springframework.expression.spel.ExpressionState;
028import org.springframework.util.NumberUtils;
029
030/**
031 * Implements the {@code multiply} operator.
032 *
033 * <p>Conversions and promotions are handled as defined in
034 * <a href="https://java.sun.com/docs/books/jls/third_edition/html/conversions.html">Section 5.6.2 of the
035 * Java Language Specification</a>, with the addiction of {@code BigDecimal}/{@code BigInteger} management:
036 *
037 * <p>If any of the operands is of a reference type, unboxing conversion (Section 5.1.8)
038 * is performed. Then:<br>
039 * If either operand is of type {@code BigDecimal}, the other is converted to {@code BigDecimal}.<br>
040 * If either operand is of type double, the other is converted to double.<br>
041 * Otherwise, if either operand is of type float, the other is converted to float.<br>
042 * If either operand is of type {@code BigInteger}, the other is converted to {@code BigInteger}.<br>
043 * Otherwise, if either operand is of type long, the other is converted to long.<br>
044 * Otherwise, both operands are converted to type int.
045 *
046 * @author Andy Clement
047 * @author Juergen Hoeller
048 * @author Sam Brannen
049 * @author Giovanni Dall'Oglio Risso
050 * @since 3.0
051 */
052public class OpMultiply extends Operator {
053
054        public OpMultiply(int pos, SpelNodeImpl... operands) {
055                super("*", pos, operands);
056        }
057
058
059        /**
060         * Implements the {@code multiply} operator directly here for certain types
061         * of supported operands and otherwise delegates to any registered overloader
062         * for types not supported here.
063         * <p>Supported operand types:
064         * <ul>
065         * <li>numbers
066         * <li>String and int ('abc' * 2 == 'abcabc')
067         * </ul>
068         */
069        @Override
070        public TypedValue getValueInternal(ExpressionState state) throws EvaluationException {
071                Object leftOperand = getLeftOperand().getValueInternal(state).getValue();
072                Object rightOperand = getRightOperand().getValueInternal(state).getValue();
073
074                if (leftOperand instanceof Number && rightOperand instanceof Number) {
075                        Number leftNumber = (Number) leftOperand;
076                        Number rightNumber = (Number) rightOperand;
077
078                        if (leftNumber instanceof BigDecimal || rightNumber instanceof BigDecimal) {
079                                BigDecimal leftBigDecimal = NumberUtils.convertNumberToTargetClass(leftNumber, BigDecimal.class);
080                                BigDecimal rightBigDecimal = NumberUtils.convertNumberToTargetClass(rightNumber, BigDecimal.class);
081                                return new TypedValue(leftBigDecimal.multiply(rightBigDecimal));
082                        }
083                        else if (leftNumber instanceof Double || rightNumber instanceof Double) {
084                                this.exitTypeDescriptor = "D";
085                                return new TypedValue(leftNumber.doubleValue() * rightNumber.doubleValue());
086                        }
087                        else if (leftNumber instanceof Float || rightNumber instanceof Float) {
088                                this.exitTypeDescriptor = "F";
089                                return new TypedValue(leftNumber.floatValue() * rightNumber.floatValue());
090                        }
091                        else if (leftNumber instanceof BigInteger || rightNumber instanceof BigInteger) {
092                                BigInteger leftBigInteger = NumberUtils.convertNumberToTargetClass(leftNumber, BigInteger.class);
093                                BigInteger rightBigInteger = NumberUtils.convertNumberToTargetClass(rightNumber, BigInteger.class);
094                                return new TypedValue(leftBigInteger.multiply(rightBigInteger));
095                        }
096                        else if (leftNumber instanceof Long || rightNumber instanceof Long) {
097                                this.exitTypeDescriptor = "J";
098                                return new TypedValue(leftNumber.longValue() * rightNumber.longValue());
099                        }
100                        else if (CodeFlow.isIntegerForNumericOp(leftNumber) || CodeFlow.isIntegerForNumericOp(rightNumber)) {
101                                this.exitTypeDescriptor = "I";
102                                return new TypedValue(leftNumber.intValue() * rightNumber.intValue());
103                        }
104                        else {
105                                // Unknown Number subtypes -> best guess is double multiplication
106                                return new TypedValue(leftNumber.doubleValue() * rightNumber.doubleValue());
107                        }
108                }
109
110                if (leftOperand instanceof String && rightOperand instanceof Integer) {
111                        int repeats = (Integer) rightOperand;
112                        StringBuilder result = new StringBuilder();
113                        for (int i = 0; i < repeats; i++) {
114                                result.append(leftOperand);
115                        }
116                        return new TypedValue(result.toString());
117                }
118
119                return state.operate(Operation.MULTIPLY, leftOperand, rightOperand);
120        }
121
122        @Override
123        public boolean isCompilable() {
124                if (!getLeftOperand().isCompilable()) {
125                        return false;
126                }
127                if (this.children.length > 1) {
128                         if (!getRightOperand().isCompilable()) {
129                                 return false;
130                         }
131                }
132                return (this.exitTypeDescriptor != null);
133        }
134        
135        @Override
136        public void generateCode(MethodVisitor mv, CodeFlow cf) {
137                getLeftOperand().generateCode(mv, cf);
138                String leftDesc = getLeftOperand().exitTypeDescriptor;
139                CodeFlow.insertNumericUnboxOrPrimitiveTypeCoercion(mv, leftDesc, this.exitTypeDescriptor.charAt(0));
140                if (this.children.length > 1) {
141                        cf.enterCompilationScope();
142                        getRightOperand().generateCode(mv, cf);
143                        String rightDesc = getRightOperand().exitTypeDescriptor;
144                        cf.exitCompilationScope();
145                        CodeFlow.insertNumericUnboxOrPrimitiveTypeCoercion(mv, rightDesc, this.exitTypeDescriptor.charAt(0));
146                        switch (this.exitTypeDescriptor.charAt(0)) {
147                                case 'I':
148                                        mv.visitInsn(IMUL);
149                                        break;
150                                case 'J':
151                                        mv.visitInsn(LMUL);
152                                        break;
153                                case 'F': 
154                                        mv.visitInsn(FMUL);
155                                        break;
156                                case 'D':
157                                        mv.visitInsn(DMUL);
158                                        break;                          
159                                default:
160                                        throw new IllegalStateException(
161                                                        "Unrecognized exit type descriptor: '" + this.exitTypeDescriptor + "'");
162                        }
163                }
164                cf.pushDescriptor(this.exitTypeDescriptor);
165        }
166
167}