Xml.java

/**
 * Copyright © 2010-2011 Nokia
 *
 * 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 com.github.restdriver.serverdriver;

import javax.xml.xpath.XPath;
import javax.xml.xpath.XPathConstants;
import javax.xml.xpath.XPathExpression;
import javax.xml.xpath.XPathExpressionException;
import javax.xml.xpath.XPathFactory;

import org.w3c.dom.Element;

import com.github.restdriver.XmlUtil;
import com.github.restdriver.serverdriver.http.response.Response;

/**
 * Provides static helper methods for XML representations.
 * 
 * @author mjg
 */
public final class Xml {
    
    private Xml() {
    }
    
    /**
     * Converts a string to an XML element.
     * 
     * @param content The content to be converted
     * @return The converted element
     * @deprecated Instead of doing asXml(response.getContent()) you can now do asXml(response).
     */
    @Deprecated
    public static Element asXml(String content) {
        return XmlUtil.asXml(content);
    }
    
    /**
     * Converts the body of the given Response to an XML element.
     * 
     * @param response The response to be converted
     * @return The converted element
     */
    public static Element asXml(Response response) {
        return XmlUtil.asXml(response.getContent());
    }
    
    /**
     * Extracts an XPath value from an XML element and returns the result as a string.
     * 
     * @param expression The XPath expression to use for extraction
     * @param element The element to use the XPath expression on
     * @return The result of evaluating the XPath expression on the element
     */
    public static String extractXPathValue(String expression, Element element) {
        
        XPath xPath = XPathFactory.newInstance().newXPath();
        
        XPathExpression compiledXPath;
        
        try {
            compiledXPath = xPath.compile(expression);
            
        } catch (XPathExpressionException e) {
            throw new RuntimeException("Failed to compile XPath '" + expression + "'", e);
            
        }
        
        try {
            return compiledXPath.evaluate(element, XPathConstants.STRING).toString();
            
        } catch (XPathExpressionException e) {
            throw new RuntimeException("Failed to evaluate XPath '" + expression + "'", e);
        }
        
    }
    
}