/**
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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.apache.activemq.filter;
import javax.jms.JMSException;
/**
* An expression which performs an operation on two expression values
*
*
*/
public abstract class ArithmeticExpression extends BinaryExpression {
protected static final int INTEGER = 1;
protected static final int LONG = 2;
protected static final int DOUBLE = 3;
/**
* @param left
* @param right
*/
public ArithmeticExpression(Expression left, Expression right) {
super(left, right);
}
public static Expression createPlus(Expression left, Expression right) {
return new ArithmeticExpression(left, right) {
protected Object evaluate(Object lvalue, Object rvalue) {
if (lvalue instanceof String) {
String text = (String)lvalue;
String answer = text + rvalue;
return answer;
} else if (lvalue instanceof Number) {
return plus((Number)lvalue, asNumber(rvalue));
}
throw new RuntimeException("Cannot call plus operation on: " + lvalue + " and: " + rvalue);
}
public String getExpressionSymbol() {
return "+";
}
};
}
public static Expression createMinus(Expression left, Expression right) {
return new ArithmeticExpression(left, right) {
protected Object evaluate(Object lvalue, Object rvalue) {
if (lvalue instanceof Number) {
return minus((Number)lvalue, asNumber(rvalue));
}
throw new RuntimeException("Cannot call minus operation on: " + lvalue + " and: " + rvalue);
}
public String getExpressionSymbol() {
return "-";
}
};
}
public static Expression createMultiply(Expression left, Expression right) {
return new ArithmeticExpression(left, right) {
protected Object evaluate(Object lvalue, Object rvalue) {
if (lvalue instanceof Number) {
return multiply((Number)lvalue, asNumber(rvalue));
}
throw new RuntimeException("Cannot call multiply operation on: " + lvalue + " and: " + rvalue);
}
public String getExpressionSymbol() {
return "*";
}
};
}
public static Expression createDivide(Expression left, Expression right) {
return new ArithmeticExpression(left, right) {
protected Object evaluate(Object lvalue, Object rvalue) {
if (lvalue instanceof Number) {
return divide((Number)lvalue, asNumber(rvalue));
}
throw new RuntimeException("Cannot call divide operation on: " + lvalue + " and: " + rvalue);
}
public String getExpressionSymbol() {
return "/";
}
};
}
public static Expression createMod(Expression left, Expression right) {
return new ArithmeticExpression(left, right) {
protected Object evaluate(Object lvalue, Object rvalue) {
if (lvalue instanceof Number) {
return mod((Number)lvalue, asNumber(rvalue));
}
throw new RuntimeException("Cannot call mod operation on: " + lvalue + " and: " + rvalue);
}
public String getExpressionSymbol() {
return "%";
}
};
}
protected Number plus(Number left, Number right) {
switch (numberType(left, right)) {
case INTEGER:
return new Integer(left.intValue() + right.intValue());
case LONG:
return new Long(left.longValue() + right.longValue());
default:
return new Double(left.doubleValue() + right.doubleValue());
}
}
protected Number minus(Number left, Number right) {
switch (numberType(left, right)) {
case INTEGER:
return new Integer(left.intValue() - right.intValue());
case LONG:
return new Long(left.longValue() - right.longValue());
default:
return new Double(left.doubleValue() - right.doubleValue());
}
}
protected Number multiply(Number left, Number right) {
switch (numberType(left, right)) {
case INTEGER:
return new Integer(left.intValue() * right.intValue());
case LONG:
return new Long(left.longValue() * right.longValue());
default:
return new Double(left.doubleValue() * right.doubleValue());
}
}
protected Number divide(Number left, Number right) {
return new Double(left.doubleValue() / right.doubleValue());
}
protected Number mod(Number left, Number right) {
return new Double(left.doubleValue() % right.doubleValue());
}
private int numberType(Number left, Number right) {
if (isDouble(left) || isDouble(right)) {
return DOUBLE;
} else if (left instanceof Long || right instanceof Long) {
return LONG;
} else {
return INTEGER;
}
}
private boolean isDouble(Number n) {
return n instanceof Float || n instanceof Double;
}
protected Number asNumber(Object value) {
if (value instanceof Number) {
return (Number)value;
} else {
throw new RuntimeException("Cannot convert value: " + value + " into a number");
}
}
public Object evaluate(MessageEvaluationContext message) throws JMSException {
Object lvalue = left.evaluate(message);
if (lvalue == null) {
return null;
}
Object rvalue = right.evaluate(message);
if (rvalue == null) {
return null;
}
return evaluate(lvalue, rvalue);
}
/**
* @param lvalue
* @param rvalue
* @return
*/
protected abstract Object evaluate(Object lvalue, Object rvalue);
}