/*
* Copyright 1999-2004 The Apache Software Foundation.
*
* 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.apache.cocoon.woody.expression;
import org.apache.avalon.framework.component.Component;
import org.apache.avalon.framework.configuration.Configurable;
import org.apache.avalon.framework.configuration.Configuration;
import org.apache.avalon.framework.configuration.ConfigurationException;
import org.apache.avalon.framework.thread.ThreadSafe;
import org.outerj.expression.DefaultFunctionFactory;
import org.outerj.expression.Expression;
import org.outerj.expression.ExpressionException;
import org.outerj.expression.FormulaParser;
import org.outerj.expression.ParseException;
/**
* Implementation of the {@link ExpressionManager} role.
*
* Custom functions can be added using configuration elements:
* <pre>
* <function name="MyFunction" class="net.foo.MyFunction"/>
* </pre>
*
* @version CVS $Id: DefaultExpressionManager.java 30932 2004-07-29 17:35:38Z vgritsenko $
*/
public class DefaultExpressionManager
implements ExpressionManager, Component, Configurable, ThreadSafe {
private DefaultFunctionFactory factory;
public void configure(Configuration config) throws ConfigurationException {
factory = new DefaultFunctionFactory();
Configuration[] functions = config.getChildren("function");
for (int i = 0; i < functions.length; i++) {
String name = functions[i].getAttribute("name");
String clazz = functions[i].getAttribute("class");
try {
factory.registerFunction(name, Class.forName(clazz));
} catch (ClassNotFoundException e) {
throw new ConfigurationException("Can not find class " + clazz + " for function " + name + ": " + e);
}
}
}
public Expression parse(String expressionString) throws ParseException, ExpressionException {
FormulaParser parser = new FormulaParser(new java.io.StringReader(expressionString), factory);
parser.sum();
Expression expression = parser.getExpression();
expression.check();
return expression;
}
}