JDOMXPathUtil.java

/**
 * Copyright 2008 The University of North Carolina at Chapel Hill
 *
 * 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 edu.unc.lib.dl.util;

import java.util.HashMap;
import java.util.Map;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.jdom2.Document;
import org.jdom2.Element;
import org.jdom2.JDOMException;
import org.jdom2.xpath.XPath;

import edu.unc.lib.dl.xml.JDOMNamespaceUtil;

/**
 * A utility class that is configured to retrieve collection identifiers
 * 
 * @author count0
 * 
 */
public class JDOMXPathUtil {
    private static final String __p = JDOMNamespaceUtil.PREMIS_V2_NS.getPrefix();

    private static XPath _dcFieldsXpath;
    private static XPath _guidXpath;
    private static XPath _isMemberOfCollectionXpath;
    private static XPath _isPartOfIDTYPEXpath;
    private static XPath _isPartOfIDVALUEXpath;
    private static final String _isPartOfRelationshipXpath = "//" + __p + ":relationship" + "[" + __p
		    + ":relationshipType = '" + JDOMNamespaceUtil.RELSEXT_NS.getURI() + "isPartOf']";
    private static XPath _pathInCollectionXpath;
    private static XPath _repoPathXpath;
    private static final String dcFieldsXpath = "//" + JDOMNamespaceUtil.DC_NS.getPrefix() + ":*";

    private static final String guidXpath = "//" + JDOMNamespaceUtil.CDR_NS.getPrefix() + ":uid";
    private static final String isMemberOfCollectionXpath = "//" + JDOMNamespaceUtil.RELSEXT_NS.getPrefix()
		    + ":isMemberOfCollection/@resource";
    private static final String isPartOfIDTYPEXpath = _isPartOfRelationshipXpath + "/" + __p
		    + ":relatedObjectIdentification/" + __p + ":relatedObjectIdentifierType";
    private static final String isPartOfIDVALUEXpath = _isPartOfRelationshipXpath + "/" + __p
		    + ":relatedObjectIdentification/" + __p + ":relatedObjectIdentifierValue";
    private static final Log log = LogFactory.getLog(JDOMXPathUtil.class);
    private static final String pathInCollectionXpath = "//" + JDOMNamespaceUtil.CDR_NS.getPrefix()
		    + ":pathInCollection";
    private static final String repoPathXpath = "//" + JDOMNamespaceUtil.CDR_NS.getPrefix() + ":repositoryPath";

    static {
	try {
	    _isMemberOfCollectionXpath = XPath.newInstance(isMemberOfCollectionXpath);
	    _isMemberOfCollectionXpath.addNamespace(JDOMNamespaceUtil.RELSEXT_NS);
	    _isMemberOfCollectionXpath.addNamespace(JDOMNamespaceUtil.RDF_NS);
	    _isPartOfIDTYPEXpath = XPath.newInstance(isPartOfIDTYPEXpath);
	    _isPartOfIDTYPEXpath.addNamespace(JDOMNamespaceUtil.PREMIS_V2_NS);
	    _isPartOfIDVALUEXpath = XPath.newInstance(isPartOfIDVALUEXpath);
	    _isPartOfIDVALUEXpath.addNamespace(JDOMNamespaceUtil.PREMIS_V2_NS);
	    _pathInCollectionXpath = XPath.newInstance(pathInCollectionXpath);
	    _pathInCollectionXpath.addNamespace(JDOMNamespaceUtil.CDR_NS);
	    _guidXpath = XPath.newInstance(guidXpath);
	    _guidXpath.addNamespace(JDOMNamespaceUtil.CDR_NS);
	    _repoPathXpath = XPath.newInstance(repoPathXpath);
	    _repoPathXpath.addNamespace(JDOMNamespaceUtil.CDR_NS);
	    _dcFieldsXpath = XPath.newInstance(dcFieldsXpath);
	    _dcFieldsXpath.addNamespace(JDOMNamespaceUtil.DC_NS);
	    _dcFieldsXpath.addNamespace(JDOMNamespaceUtil.CDR_NS);
	} catch (JDOMException e) {
	    log.error("Bad Configuration for JDOMXPathUtil", e);
	    throw new IllegalArgumentException("Bad Configuration for JDOMXPathUtil", e);
	}
    }

    public static Map<String, String> getDCFields(Document doc) {
	HashMap<String, String> result = new HashMap<String, String>();
	try {
	    for (Object con : _dcFieldsXpath.selectNodes(doc)) {
		if (con instanceof Element) {
		    Element el = (Element) con;
		    String value = el.getTextTrim();
		    String name = el.getName();
		    result.put(name, value);
		}
	    }
	} catch (JDOMException e) {
	    throw new Error("Programming error, XPath should be valid", e);
	}
	return result;
    }

    /**
     * Attempt to find the globally unique identifier in the FOXML Document.
     * 
     * @param foxml
     * @return either an identifier or null
     */
    public static String getGUID(Document foxml) {
	String guid = null;
	try {
	    guid = _guidXpath.valueOf(foxml).trim();
	    if ("".equals(guid)) {
		guid = null;
		log.info("Object is missing it's GUID: " + _guidXpath.getXPath());
	    }
	} catch (JDOMException e) {
	    log.info("Problem finding collection identifier XPaths", e);
	}
	return guid;
    }

    /**
     * Attempt to find a collection-based repository path in the FOXML Document.
     * 
     * @param foxml
     * @return either an identifier or null
     */
    /*
     * public static String getRepositoryPath(Document foxml) { String path =
     * null; try { path = _repoPathXpath.valueOf(foxml).trim(); if
     * ("".equals(path)) { path = null; log.info("Object is missing it's
     * repository path: " + _repoPathXpath.getXPath()); } } catch (JDOMException
     * e) { log.info("Problem finding repository path in FOXML via XPath.", e); }
     * return path; }
     */

    public static String getIsMemberOfCollectionPID(Document foxml) {
	String result = null;
	try {
	    result = _isMemberOfCollectionXpath.valueOf(foxml).trim();
	} catch (JDOMException e) {
	    log.warn("JDOMException trying to get collection from foxml", e);
	}
	if ("".equals(result)) {
	    result = null;
	}
	return result;
    }

    /**
     * @param foxml
     * @return a two string array containing the identifier type and the
     *         identifier value This functions returns an identifier type and
     *         value for the isPartOf relationship defined in PREMIS. The PREMIS
     *         supplied isPartOf information is used to link the top object in a
     *         SIP to it's containing object in the repository.
     */
    public static String[] getIsPartOfRelatedObject(Document foxml) {
	String[] result = new String[2];
	String type = null;
	String value = null;
	try {
	    type = _isPartOfIDTYPEXpath.valueOf(foxml).trim();
	    value = _isPartOfIDVALUEXpath.valueOf(foxml).trim();
	    result[0] = type;
	    result[1] = value;
	} catch (JDOMException e) {
	    log.warn("JDOMException trying to get collection from foxml", e);
	}
	if ("".equals(type) || "".equals(value)) {
	    result = null;
	}
	return result;
    }

    public static String getPathInCollection(Document foxml) {
	String result = null;
	try {
	    result = _pathInCollectionXpath.valueOf(foxml).trim();
	} catch (JDOMException e) {
	    log.warn("JDOMException trying to get path in collection from foxml", e);
	}
	if ("".equals(result)) {
	    result = null;
	}
	return result;
    }
}