/**
* 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.camel.language.jxpath;
import org.apache.camel.Exchange;
import org.apache.camel.ExpressionEvaluationException;
import org.apache.camel.support.ExpressionSupport;
import org.apache.commons.jxpath.CompiledExpression;
import org.apache.commons.jxpath.JXPathContext;
import org.apache.commons.jxpath.JXPathException;
/**
* <a href="http://commons.apache.org/jxpath/">JXPath</a> {@link org.apache.camel.Expression} support
*/
public class JXPathExpression extends ExpressionSupport {
private final String expression;
private CompiledExpression compiledExpression;
private final Class<?> type;
/**
* Creates a new JXPathExpression instance
*
* @param expression the JXPath expression to be evaluated
* @param type the expected result type
*/
public JXPathExpression(String expression, Class<?> type) {
super();
this.expression = expression;
this.type = type;
}
public <T> T evaluate(Exchange exchange, Class<T> tClass) {
try {
JXPathContext context = JXPathContext.newContext(exchange);
Object result = getJXPathExpression().getValue(context, type);
assertResultType(exchange, result);
return exchange.getContext().getTypeConverter().convertTo(tClass, result);
} catch (JXPathException e) {
throw new ExpressionEvaluationException(this, exchange, e);
}
}
/*
* Check if the result is of the specified type
*/
private void assertResultType(Exchange exchange, Object result) {
if (result != null && !type.isAssignableFrom(result.getClass())) {
throw new JXPathException("JXPath result type is " + result.getClass() + " instead of required type " + type);
}
}
@Override
protected String assertionFailureMessage(Exchange exchange) {
return expression;
}
/*
* Get a compiled expression instance for better performance
*/
private synchronized CompiledExpression getJXPathExpression() {
if (compiledExpression == null) {
compiledExpression = JXPathContext.compile(expression);
}
return compiledExpression;
}
@Override
public String toString() {
return "JXpath[" + expression + "]";
}
}