001////////////////////////////////////////////////////////////////////////////////
002// checkstyle: Checks Java source code for adherence to a set of rules.
003// Copyright (C) 2001-2015 the original author or authors.
004//
005// This library is free software; you can redistribute it and/or
006// modify it under the terms of the GNU Lesser General Public
007// License as published by the Free Software Foundation; either
008// version 2.1 of the License, or (at your option) any later version.
009//
010// This library is distributed in the hope that it will be useful,
011// but WITHOUT ANY WARRANTY; without even the implied warranty of
012// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
013// Lesser General Public License for more details.
014//
015// You should have received a copy of the GNU Lesser General Public
016// License along with this library; if not, write to the Free Software
017// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
018////////////////////////////////////////////////////////////////////////////////
019
020package com.puppycrawl.tools.checkstyle.api;
021
022import java.io.IOException;
023import java.io.InputStream;
024import java.util.HashMap;
025import java.util.Map;
026
027import javax.xml.parsers.ParserConfigurationException;
028import javax.xml.parsers.SAXParserFactory;
029
030import org.xml.sax.InputSource;
031import org.xml.sax.SAXException;
032import org.xml.sax.SAXParseException;
033import org.xml.sax.XMLReader;
034import org.xml.sax.helpers.DefaultHandler;
035
036import com.google.common.collect.Maps;
037
038/**
039 * Contains the common implementation of a loader, for loading a configuration
040 * from an XML file.
041 * <p>
042 * The error handling policy can be described as being austere, dead set,
043 * disciplinary, dour, draconian, exacting, firm, forbidding, grim, hard, hard-
044 * boiled, harsh, harsh, in line, iron-fisted, no-nonsense, oppressive,
045 * persnickety, picky, prudish, punctilious, puritanical, rigid, rigorous,
046 * scrupulous, set, severe, square, stern, stickler, straight, strait-laced,
047 * stringent, stuffy, stuffy, tough, unpermissive, unsparing and uptight.
048 * </p>
049 *
050 * @author Oliver Burn
051 */
052public abstract class AbstractLoader
053    extends DefaultHandler {
054    /** Maps public id to resolve to resource name for the DTD. */
055    private final Map<String, String> publicIdToResourceNameMap;
056    /** Parser to read XML files. **/
057    private final XMLReader parser;
058
059    /**
060     * Creates a new instance.
061     * @param publicId the public ID for the DTD to resolve
062     * @param dtdResourceName the resource for the DTD
063     * @throws SAXException if an error occurs
064     * @throws ParserConfigurationException if an error occurs
065     */
066    protected AbstractLoader(String publicId, String dtdResourceName)
067        throws SAXException, ParserConfigurationException {
068        this(new HashMap<String, String>(1));
069        publicIdToResourceNameMap.put(publicId, dtdResourceName);
070    }
071
072    /**
073     * Creates a new instance.
074     * @param publicIdToResourceNameMap maps public IDs to DTD resource names
075     * @throws SAXException if an error occurs
076     * @throws ParserConfigurationException if an error occurs
077     */
078    protected AbstractLoader(Map<String, String> publicIdToResourceNameMap)
079        throws SAXException, ParserConfigurationException {
080        this.publicIdToResourceNameMap =
081            Maps.newHashMap(publicIdToResourceNameMap);
082        final SAXParserFactory factory = SAXParserFactory.newInstance();
083        factory.setValidating(true);
084        factory.setNamespaceAware(true);
085        parser = factory.newSAXParser().getXMLReader();
086        parser.setContentHandler(this);
087        parser.setEntityResolver(this);
088        parser.setErrorHandler(this);
089    }
090
091    /**
092     * Parses the specified input source.
093     * @param inputSource the input source to parse.
094     * @throws IOException if an error occurs
095     * @throws SAXException in an error occurs
096     */
097    public void parseInputSource(InputSource inputSource)
098        throws IOException, SAXException {
099        parser.parse(inputSource);
100    }
101
102    @Override
103    public InputSource resolveEntity(String publicId, String systemId)
104        throws SAXException, IOException {
105        if (publicIdToResourceNameMap.keySet().contains(publicId)) {
106            final String dtdResourceName =
107                    publicIdToResourceNameMap.get(publicId);
108            final ClassLoader loader =
109                getClass().getClassLoader();
110            final InputStream dtdIs =
111                loader.getResourceAsStream(dtdResourceName);
112
113            return new InputSource(dtdIs);
114        }
115        return super.resolveEntity(publicId, systemId);
116    }
117
118    @Override
119    public void error(SAXParseException exception) throws SAXException {
120        throw exception;
121    }
122
123    @Override
124    public void fatalError(SAXParseException exception) throws SAXException {
125        throw exception;
126    }
127}