/*
* Copyright 2002-2012 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.core.convert.TypeDescriptor;
import org.springframework.expression.EvaluationException;
import org.springframework.expression.Operation;
import org.springframework.expression.TypeConverter;
import org.springframework.expression.TypedValue;
import org.springframework.expression.spel.ExpressionState;
import org.springframework.util.Assert;
/**
* The plus operator will:
* <ul>
* <li>add doubles (floats are represented as doubles)
* <li>add longs
* <li>add integers
* <li>concatenate strings
* </ul>
* It can be used as a unary operator for numbers (double/long/int). 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 Ivo Smid
* @since 3.0
*/
public class OpPlus extends Operator {
public OpPlus(int pos, SpelNodeImpl... operands) {
super("+", pos, operands);
Assert.notEmpty(operands);
}
@Override
public TypedValue getValueInternal(ExpressionState state) throws EvaluationException {
SpelNodeImpl leftOp = getLeftOperand();
SpelNodeImpl rightOp = getRightOperand();
if (rightOp == null) { // If only one operand, then this is unary plus
Object operandOne = leftOp.getValueInternal(state).getValue();
if (operandOne instanceof Number) {
if (operandOne instanceof Double || operandOne instanceof Long) {
return new TypedValue(operandOne);
} else if (operandOne instanceof Float) {
return new TypedValue(((Number) operandOne).floatValue());
} else {
return new TypedValue(((Number) operandOne).intValue());
}
}
return state.operate(Operation.ADD, operandOne, null);
}
else {
final TypedValue operandOneValue = leftOp.getValueInternal(state);
final Object operandOne = operandOneValue.getValue();
final TypedValue operandTwoValue = rightOp.getValueInternal(state);
final Object operandTwo = operandTwoValue.getValue();
if (operandOne instanceof Number && operandTwo instanceof Number) {
Number op1 = (Number) operandOne;
Number op2 = (Number) operandTwo;
if (op1 instanceof Double || op2 instanceof Double) {
return new TypedValue(op1.doubleValue() + op2.doubleValue());
} else if (op1 instanceof Float || op2 instanceof Float) {
return new TypedValue(op1.floatValue() + op2.floatValue());
} else if (op1 instanceof Long || op2 instanceof Long) {
return new TypedValue(op1.longValue() + op2.longValue());
} else { // TODO what about overflow?
return new TypedValue(op1.intValue() + op2.intValue());
}
} else if (operandOne instanceof String && operandTwo instanceof String) {
return new TypedValue(new StringBuilder((String) operandOne).append((String) operandTwo).toString());
} else if (operandOne instanceof String) {
StringBuilder result = new StringBuilder((String) operandOne);
result.append((operandTwo == null ? "null" : convertTypedValueToString(operandTwoValue, state)));
return new TypedValue(result.toString());
} else if (operandTwo instanceof String) {
StringBuilder result = new StringBuilder((operandOne == null ? "null" : convertTypedValueToString(
operandOneValue, state)));
result.append((String) operandTwo);
return new TypedValue(result.toString());
}
return state.operate(Operation.ADD, operandOne, operandTwo);
}
}
@Override
public String toStringAST() {
if (children.length<2) { // unary plus
return new StringBuilder().append("+").append(getLeftOperand().toStringAST()).toString();
}
return super.toStringAST();
}
@Override
public SpelNodeImpl getRightOperand() {
if (children.length < 2) {
return null;
}
return children[1];
}
/**
* Convert operand value to string using registered converter or using
* {@code toString} method.
*
* @param value typed value to be converted
* @param state expression state
* @return {@code TypedValue} instance converted to {@code String}
*/
private static String convertTypedValueToString(TypedValue value, ExpressionState state) {
final TypeConverter typeConverter = state.getEvaluationContext().getTypeConverter();
final TypeDescriptor typeDescriptor = TypeDescriptor.valueOf(String.class);
if (typeConverter.canConvert(value.getTypeDescriptor(), typeDescriptor)) {
final Object obj = typeConverter.convertValue(value.getValue(), value.getTypeDescriptor(), typeDescriptor);
return String.valueOf(obj);
} else {
return String.valueOf(value.getValue());
}
}
}