scriptella.driver.xpath.XPathExpressionCompiler Maven / Gradle / Ivy
/*
* Copyright 2006-2012 The Scriptella Project Team.
*
* 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 scriptella.driver.xpath;
import scriptella.util.LRUMap;
import javax.xml.xpath.XPathExpression;
import javax.xml.xpath.XPathExpressionException;
import javax.xml.xpath.XPathFactory;
import java.util.Map;
/**
* Represents a facade for compiling xpath expressions.
* Expressions caching is also supported.
*
* @author Fyodor Kupolov
* @version 1.0
*/
class XPathExpressionCompiler {
private static final int DEFAULT_SIZE = 100;
private static final XPathFactory XPATH_FACTORY = XPathFactory.newInstance();
private Map cache = new LRUMap(DEFAULT_SIZE);
public XPathExpression compile(final String expression) {
String trimmedEx = expression.trim();
XPathExpression ex = cache.get(trimmedEx);
if (ex == null) {
try {
cache.put(trimmedEx, ex = XPATH_FACTORY.newXPath().compile(trimmedEx));
} catch (XPathExpressionException e) {
throw new XPathProviderException("Unable to compile XPath query: " + trimmedEx, e);
}
}
return ex;
}
}