org.expath.exist.ftclient.GetResourceMetadataFunction.java Source code

Introduction

Here is the source code for org.expath.exist.ftclient.GetResourceMetadataFunction.java

Source

/*
 *  eXist Open Source Native XML Database
 *  Copyright (C) 2011 The eXist Project
 *  http://exist-db.org
 *
 *  This program is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Lesser General Public License
 *  as published by the Free Software Foundation; either version 2
 *  of the License, or (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public
 *  License along with this library; if not, write to the Free Software
 *  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 *
 *  $Id$
 */
package org.expath.exist.ftclient;

import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.UnsupportedEncodingException;

import javax.xml.transform.stream.StreamResult;

import org.apache.commons.io.input.CloseShieldInputStream;
import org.apache.log4j.Logger;
import org.exist.dom.QName;
import org.exist.memtree.DocumentBuilderReceiver;
import org.exist.memtree.MemTreeBuilder;
import org.exist.xquery.BasicFunction;
import org.exist.xquery.Cardinality;
import org.exist.xquery.FunctionSignature;
import org.exist.xquery.XPathException;
import org.exist.xquery.XQueryContext;
import org.exist.xquery.value.FunctionParameterSequenceType;
import org.exist.xquery.value.FunctionReturnSequenceType;
import org.exist.xquery.value.IntegerValue;
import org.exist.xquery.value.NodeValue;
import org.exist.xquery.value.Sequence;
import org.exist.xquery.value.SequenceType;
import org.exist.xquery.value.Type;
import org.exist.xquery.value.ValueSequence;
import org.w3c.dom.Document;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
import org.xml.sax.XMLReader;

/**
 * Implements a method for getting a resource metadata.
 * 
 * @author Claudius Teodorescu <claudius.teodorescu@gmail.com>
 */
public class GetResourceMetadataFunction extends BasicFunction {

    private static final Logger log = Logger.getLogger(GetResourceMetadataFunction.class);

    public final static FunctionSignature signature = new FunctionSignature(new QName("get-resource-metadata",
            ExistExpathFTClientModule.NAMESPACE_URI, ExistExpathFTClientModule.PREFIX),
            "Get metadata of a resource.",
            new SequenceType[] {
                    new FunctionParameterSequenceType("connection-handle", Type.LONG, Cardinality.EXACTLY_ONE,
                            "The connection handle"),
                    new FunctionParameterSequenceType("remote-resource-path", Type.STRING, Cardinality.EXACTLY_ONE,
                            "The path for resource to be retrieved.") },
            new FunctionReturnSequenceType(Type.ANY_TYPE, Cardinality.ZERO_OR_ONE,
                    "the metadata retrieved, wrapped in element(resource)."));

    public GetResourceMetadataFunction(XQueryContext context) {
        super(context, signature);
    }

    @Override
    public Sequence eval(Sequence[] args, Sequence contextSequence) throws XPathException {

        Sequence result = new ValueSequence();

        StreamResult resultAsStreamResult = null;

        try {
            resultAsStreamResult = ro.kuberam.libs.java.ftclient.GetResourceMetadata
                    .getResourceMetadata(ExistExpathFTClientModule.retrieveRemoteConnection(context,
                            ((IntegerValue) args[0].itemAt(0)).getLong()), args[1].getStringValue());
        } catch (Exception ex) {
            throw new XPathException(ex.getMessage());
        }

        ByteArrayInputStream resultDocAsInputStream = null;
        try {
            resultDocAsInputStream = new ByteArrayInputStream(
                    resultAsStreamResult.getWriter().toString().getBytes("UTF-8"));
        } catch (UnsupportedEncodingException ex) {
            throw new XPathException(ex.getMessage());
        }

        XMLReader reader = null;

        context.pushDocumentContext();
        try {
            InputSource src = new InputSource(new CloseShieldInputStream(resultDocAsInputStream));

            reader = context.getBroker().getBrokerPool().getParserPool().borrowXMLReader();
            MemTreeBuilder builder = context.getDocumentBuilder();
            DocumentBuilderReceiver receiver = new DocumentBuilderReceiver(builder, true);
            reader.setContentHandler(receiver);
            reader.parse(src);
            Document doc = receiver.getDocument();

            result = (NodeValue) doc;
        } catch (SAXException saxe) {
            // do nothing, we will default to trying to return a string below
        } catch (IOException ioe) {
            // do nothing, we will default to trying to return a string below
        } finally {
            context.popDocumentContext();

            if (reader != null) {
                context.getBroker().getBrokerPool().getParserPool().returnXMLReader(reader);
            }
        }

        return result;
    }
}