/*
* Copyright 2004-2009 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.springmodules.validation.util.fel.parser;
import ognl.Ognl;
import ognl.OgnlException;
import org.springmodules.validation.util.fel.FelEvaluationException;
import org.springmodules.validation.util.fel.FelParseException;
import org.springmodules.validation.util.fel.Function;
import org.springmodules.validation.util.fel.FunctionExpressionParser;
/**
* A {@link FunctionExpressionParser} implementation that knows how to parse OGNL expressions and
* return the appropriate function.
*
* @author Uri Boness
*/
public class OgnlFunctionExpressionParser implements FunctionExpressionParser {
public Function parse(String expression) {
return new OgnlFunction(expression);
}
/**
* A function that is associated with an OGNL expression and evaluates this expression on
* the given object.
*/
protected class OgnlFunction implements Function {
private String expressionAsString;
private Object ognlExpression;
public OgnlFunction(String expressionAsString) {
this.expressionAsString = expressionAsString;
try {
this.ognlExpression = Ognl.parseExpression(expressionAsString);
} catch (OgnlException oe) {
throw new FelParseException("Could not parse OGNL expression '" + expressionAsString + "'", oe);
}
}
public Object evaluate(Object argument) {
try {
return Ognl.getValue(ognlExpression, argument);
} catch (OgnlException oe) {
throw new FelEvaluationException("Could not evaluate OGNL expression '" + expressionAsString +
"' on argument '" + String.valueOf(argument), oe);
}
}
}
}