XmlConverterUtils.java

/*
 * 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.compass.core.converter.mapping.xsem;

import org.compass.core.converter.ConversionException;
import org.compass.core.mapping.xsem.XPathEnabledMapping;
import org.compass.core.xml.XmlObject;
import org.compass.core.xml.XmlXPathExpression;

/**
 * A set of utilities for xml conversion.
 *
 * @author kimchy
 */
public abstract class XmlConverterUtils {

    /**
     * Executes the given xpath expression (using {@link XPathEnabledMapping} and returns
     * a list of xml objects.
     * <p/>
     * Handles compilation of xpath expression if possible, and storing the compiled xpath
     * expressions in the {@link XPathEnabledMapping}.
     *
     * @param xmlObject    The xml object to execute the xpath expression against.
     * @param xpathMapping The xpath mapping definiton
     * @return The list of xml objects matching the xpath expression
     * @throws ConversionException
     */
    public static XmlObject[] select(XmlObject xmlObject, XPathEnabledMapping xpathMapping) throws ConversionException {
        if (xpathMapping.getXPathExpression() != null) {
            try {
                return xpathMapping.getXPathExpression().select(xmlObject);
            } catch (Exception e) {
                throw new ConversionException("Failed to select xpath [" + xpathMapping.getXPath() + "]", e);
            }
        }
        if (xmlObject.canCompileXpath()) {
            XmlXPathExpression xPathExpression;
            try {
                xPathExpression = xmlObject.compile(xpathMapping.getXPath());
            } catch (Exception e) {
                throw new ConversionException("Failed to compile xpath [" + xpathMapping.getXPath() + "]", e);
            }
            xpathMapping.setXPathExpression(xPathExpression);
            try {
                return xPathExpression.select(xmlObject);
            } catch (Exception e) {
                throw new ConversionException("Failed to select xpath [" + xpathMapping.getXPath() + "]", e);
            }
        }
        try {
            return xmlObject.selectPath(xpathMapping.getXPath());
        } catch (Exception e) {
            throw new ConversionException("Failed to select xpath [" + xpathMapping.getXPath() + "]", e);
        }
    }
}