xsltdisseminationcrosswalk.java

dspace 用j2ee架构的一个数字图书馆.开源程序

/*
 * XSLTDisseminationCrosswalk.java
 *
 * Version: $Revision: 1.1 $
 *
 * Date: $Date: 2006/03/17 00:04:38 $
 *
 * Copyright (c) 2002-2005, Hewlett-Packard Company and Massachusetts
 * Institute of Technology.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 * - Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 *
 * - Redistributions in binary form must reproduce the above copyright
 * notice, this list of conditions and the following disclaimer in the
 * documentation and/or other materials provided with the distribution.
 *
 * - Neither the name of the Hewlett-Packard Company nor the name of the
 * Massachusetts Institute of Technology nor the names of their
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR
 * TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
 * USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
 * DAMAGE.
 */

package org.dspace.content.crosswalk;

import java.io.InputStream;
import java.io.IOException;
import java.sql.SQLException;
import java.util.Iterator;
import java.util.List;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Properties;
import java.util.Enumeration;
import java.io.OutputStream;
import java.io.StringReader;
import java.io.File;
import java.io.FileInputStream;

import java.sql.SQLException;
import org.apache.log4j.Logger;

import org.dspace.core.Context;
import org.dspace.core.Constants;
import org.dspace.content.Item;
import org.dspace.content.DCDate;
import org.dspace.content.DCValue;
import org.dspace.content.DSpaceObject;
import org.dspace.authorize.AuthorizeException;
import org.dspace.core.ConfigurationManager;
import org.dspace.core.SelfNamedPlugin;

import org.jdom.*;
import org.jdom.output.XMLOutputter;
import org.jdom.output.Format;
import org.jdom.input.SAXBuilder;
import org.jdom.input.JDOMParseException;
import org.jdom.xpath.XPath;
import org.jdom.transform.XSLTransformer;
import org.jdom.transform.XSLTransformException;

/**
 * Configurable XSLT-driven dissemination Crosswalk
 * <p>
 * See the XSLTCrosswalk superclass for details on configuration.
 * <p>
 * <h3>Additional Configuration of Dissemination crosswalk:</h3>
 * The disseminator also needs to be configured with an XML Namespace
 * (including prefix and URI) and an XML Schema for output format.  This
 * is configured on additional properties in the DSpace Configuration, i.e.:
 * <pre>
 *   crosswalk.dissemination.<i>PluginName</i>.namespace.<i>Prefix</i> = <i>namespace-URI</i>
 *   crosswalk.dissemination.<i>PluginName</i>.schemaLocation = <i>schemaLocation value</i>
 *   crosswalk.dissemination.<i>PluginName</i>.preferList = <i>boolean</i> (default is false)
 * </pre>
 * For example:
 * <pre>
 *   crosswalk.dissemination.qdc.namespace.dc = http://purl.org/dc/elements/1.1/
 *   crosswalk.dissemination.qdc.namespace.dcterms = http://purl.org/dc/terms/
 *   crosswalk.dissemination.qdc.schemaLocation = \
 *      http://purl.org/dc/elements/1.1/ http://dublincore.org/schemas/xmls/qdc/2003/04/02/qualifieddc.xsd
 *   crosswalk.dissemination.qdc.preferList = true
 * </pre>
 *
 * @author Larry Stone
 * @version $Revision: 1.1 $
 * @see XSLTCrosswalk
 */
public class XSLTDisseminationCrosswalk
    extends XSLTCrosswalk
    implements DisseminationCrosswalk
{
    /** log4j category */
    private static Logger log = Logger.getLogger(XSLTDisseminationCrosswalk.class);

    private final static String DIRECTION = "dissemination";

    private static XMLOutputter outputPretty = new XMLOutputter(Format.getPrettyFormat());

    private static String aliases[] = makeAliases(DIRECTION);

    public static String[] getPluginNames()
    {
        return aliases;
    }

    // namespace and schema; don't worry about initializing these
    // until there's an instance, so do it in constructor.
    private String schemaLocation = null;

    private Namespace namespaces[] = null;

    private String rootName = null;

    private boolean preferList = false;

    // load the namespace and schema from config
    private void init()
        throws CrosswalkInternalException
    {
        if (namespaces != null || schemaLocation != null)
            return;
        String myAlias = getPluginInstanceName();
        if (myAlias == null)
        {
            log.error("Must use PluginManager to instantiate XSLTDisseminationCrosswalk so the class knows its name.");
            throw new CrosswalkInternalException("Must use PluginManager to instantiate XSLTDisseminationCrosswalk so the class knows its name.");
        }

        // all configs for this plugin instance start with this:
        String prefix = CONFIG_PREFIX+DIRECTION+"."+myAlias+".";

        // get the schema location string, should already be in the
        // right format for value of "schemaLocation" attribute.
        schemaLocation = ConfigurationManager.getProperty(prefix+"schemaLocation");
        if (schemaLocation == null)
            log.warn("No schemaLocation for crosswalk="+myAlias+", key="+prefix+"schemaLocation");

        // sanity check: schemaLocation should have space.
        else if (schemaLocation.length() > 0 && schemaLocation.indexOf(" ") < 0)
            log.warn("Possible INVALID schemaLocation (no space found) for crosswalk="+
                      myAlias+", key="+prefix+"schemaLocation"+
                      "\n\tCorrect format is \"{namespace} {schema-URL}\"");

        // grovel for namespaces of the form:
        //  crosswalk.diss.{PLUGIN_NAME}.namespace.{PREFIX} = {URI}
        String nsPrefix = prefix + "namespace.";
        Enumeration pe = ConfigurationManager.propertyNames();
        List nsList = new ArrayList();
        while (pe.hasMoreElements())
        {
            String key = (String)pe.nextElement();
            if (key.startsWith(nsPrefix))
                nsList.add(Namespace.getNamespace(key.substring(nsPrefix.length()),
                             ConfigurationManager.getProperty(key)));
        }
        namespaces = (Namespace[])nsList.toArray(new Namespace[nsList.size()]);

        preferList = ConfigurationManager.getBooleanProperty(prefix+"preferList", false);
    }

    public Namespace[] getNamespaces()
    {
        try
        {
            init();
        }
        catch (CrosswalkInternalException e)
        {
            log.error(e.toString());
        }
        return namespaces;
    }

    public String getSchemaLocation()
    {
        try
        {
            init();
        }
        catch (CrosswalkInternalException e)
        {
            log.error(e.toString());
        }
        return schemaLocation;
    }

    public Element disseminateElement(DSpaceObject dso)
        throws CrosswalkException,
               IOException, SQLException, AuthorizeException
    {
        init();

        if (dso.getType() != Constants.ITEM)
            throw new CrosswalkObjectNotSupported("XSLTDisseminationCrosswalk can only crosswalk an Item.");
        Item item = (Item)dso;
        XSLTransformer xform = getTransformer(DIRECTION);
        if (xform == null)
            throw new CrosswalkInternalException("Failed to initialize transformer, probably error loading stylesheet.");

        try
        {
            Document ddim = new Document(getDim(item));
            Document result = xform.transform(ddim);
            return result.getRootElement();
        }
        catch (XSLTransformException e)
        {
            log.error("Got error: "+e.toString());
            throw new CrosswalkInternalException("XSL translation failed: "+e.toString());
        }
    }

    public List disseminateList(DSpaceObject dso)
        throws CrosswalkException,
               IOException, SQLException, AuthorizeException
    {
        init();

        if (dso.getType() != Constants.ITEM)
            throw new CrosswalkObjectNotSupported("XSLTDisseminationCrosswalk can only crosswalk an Item.");
        Item item = (Item)dso;
        XSLTransformer xform = getTransformer(DIRECTION);
        if (xform == null)
            throw new CrosswalkInternalException("Failed to initialize transformer, probably error loading stylesheet.");

        try
        {
            return xform.transform(getDim(item).getChildren());
        }
        catch (XSLTransformException e)
        {
            log.error("Got error: "+e.toString());
            throw new CrosswalkInternalException("XSL translation failed: "+e.toString());
        }
    }


    // build DIM expression of Item's metadata.
    private Element getDim(Item item)
    {
        DCValue[] dc = item.getMetadata(Item.ANY, Item.ANY, Item.ANY, Item.ANY);
        Element dim = new Element("dim", DIM_NS);
        for (int i = 0; i < dc.length; i++)
        {
            Element field = new Element("field", DIM_NS);
            field.setAttribute("mdschema", dc[i].schema);
            field.setAttribute("element", dc[i].element);
            if (dc[i].qualifier != null)
                field.setAttribute("qualifier", dc[i].qualifier);
            if (dc[i].language != null)
                field.setAttribute("lang", dc[i].language);
            if (dc[i].value != null)
                field.setText(dc[i].value);
            dim.addContent(field);
        }
        return dim;
    }

    public boolean canDisseminate(DSpaceObject dso)
    {
        return dso.getType() == Constants.ITEM;
    }

    public boolean preferList()
    {
        try
        {
            init();
        }
        catch (CrosswalkInternalException e)
        {
            log.error(e.toString());
        }
        return preferList;
    }
}