QTI21ContentPackage.java

/*
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Copyright (c) 2008, University of Southampton
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
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package org.olat.ims.qti21;

import java.io.IOException;
import java.io.InputStream;
import java.nio.file.Files;
import java.nio.file.Path;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Iterator;
import java.util.List;

import javax.xml.XMLConstants;
import javax.xml.namespace.NamespaceContext;
import javax.xml.xpath.XPath;
import javax.xml.xpath.XPathConstants;
import javax.xml.xpath.XPathException;
import javax.xml.xpath.XPathFactory;

import org.w3c.dom.NodeList;
import org.xml.sax.InputSource;

public class QTI21ContentPackage {
	public static final String MANIFEST_FILE_NAME = "imsmanifest.xml";
	private static final String [] TEST_EXPRESSION =
	{
		"/imscp:manifest/imscp:resources/imscp:resource[@type='imsqti_test_xmlv2p1']/@href",
		"/imscp:manifest/imscp:resources/imscp:resource[@type='imsqti_assessment_xmlv2p1']/@href" /* incorrect -- for backwards compatibility */
	};
	private static final String [] ITEM_EXPRESSION =
	{
		"/imscp:manifest/imscp:resources/imscp:resource[@type='imsqti_item_xmlv2p0']/@href",
		"/imscp:manifest/imscp:resources/imscp:resource[@type='imsqti_item_xmlv2p1']/@href",
		"/imscp:manifest/imscp:resources/imscp:resource[@type='imsqti_item_xml_v2p1']/@href" /* for aqurate */
	};

	private class QTINamespaceContext implements NamespaceContext
	{
		private static final String DEFAULT_NAME_SPACE = "imscp";
		private static final String DEFAULT_NAME_SPACE_URI = "http://www.imsglobal.org/xsd/imscp_v1p1";

		private String prefix;
		private String uri;

		public QTINamespaceContext()
		{
			this(DEFAULT_NAME_SPACE, DEFAULT_NAME_SPACE_URI);
		}

		public QTINamespaceContext(String prefix, String uri)
		{
			this.prefix = prefix;
			this.uri = uri;
		}

		public String getNamespaceURI(String prefix)
		{
			if (prefix.equals(this.prefix))
				return uri;
			else if (prefix.equals(XMLConstants.XML_NS_PREFIX))
				return XMLConstants.XML_NS_URI;
			else if (prefix.equals(XMLConstants.XMLNS_ATTRIBUTE))
				return XMLConstants.XMLNS_ATTRIBUTE_NS_URI;
			else
				return "";
		}

		public String getPrefix(String uri)
		{
			if (uri.equals(this.uri))
				return prefix;
			else if (uri.equals(XMLConstants.XML_NS_URI))
				return XMLConstants.XML_NS_PREFIX;
			else if (uri.equals(XMLConstants.XMLNS_ATTRIBUTE_NS_URI))
				return XMLConstants.XMLNS_ATTRIBUTE;
			else
				return null;
		}

		public Iterator<String> getPrefixes(String namespaceURI)
		{
			Collection<String> collection = new ArrayList<String>();
			collection.add(getPrefix(namespaceURI));

			return collection.iterator();
		}
	}
	
	private Path manifestFile;

	public QTI21ContentPackage(Path file) {
		this.manifestFile = file;
	}

	public Path getManifest() {
		return manifestFile;
	}
	
	public boolean hasTest() {
		if(manifestFile == null || manifestFile.getParent() == null) {
			return false;
		}
		
		NodeList list = null;
		for (String s : TEST_EXPRESSION) {
			list = getNodeList(s);
			if (list.getLength() > 0) {
				break;
			}
		}

		if (list == null || list.getLength() == 0) {
			return false;
		}

		Path testPath = manifestFile.getParent().resolve(list.item(0).getNodeValue());
		return testPath != null && Files.exists(testPath);
	}

	public Path getTest() throws IOException {
		NodeList list = null;
		for (String s : TEST_EXPRESSION) {
			list = getNodeList(s);
			if (list.getLength() > 0)
				break;
		}

		if (list == null || list.getLength() == 0) {
			throw new IOException("Cannot find test.");
		}

		return manifestFile.getParent().resolve(list.item(0).getNodeValue());
	}

	public Path[] getItems() {
		List<NodeList> list = new ArrayList<NodeList>();
		int length=0;
		for (String s : ITEM_EXPRESSION) {
			NodeList l = getNodeList(s);
			list.add(l);
			length +=  l.getLength();
		}

		Path[] result = new Path[length];

		int j=0;
		for (NodeList l : list) {
			for (int i=0; i < l.getLength(); i++, j++)
				result[j] = manifestFile.getParent().resolve(l.item(i).getNodeValue());
		}
		
		return result;
	}

	private NodeList getNodeList(String expression) {
		try (InputStream input=Files.newInputStream(manifestFile)) {
			XPath xpath = XPathFactory.newInstance().newXPath();
			xpath.setNamespaceContext(new QTINamespaceContext());
			InputSource source = new InputSource(input);

			return (NodeList) xpath.evaluate(expression, source, XPathConstants.NODESET);
		} catch (IOException | XPathException ex) {
			throw new RuntimeException("", ex);
		}
	}
}