001: ////////////////////////////////////////////////////////////////////////////////
002: // checkstyle: Checks Java source code for adherence to a set of rules.
003: // Copyright (C) 2001-2007 Oliver Burn
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: package com.puppycrawl.tools.checkstyle.api;
020:
021: import java.io.IOException;
022: import java.io.InputStream;
023: import java.util.Map;
024: import java.util.HashMap;
025: import javax.xml.parsers.ParserConfigurationException;
026: import javax.xml.parsers.SAXParserFactory;
027: import org.xml.sax.InputSource;
028: import org.xml.sax.SAXException;
029: import org.xml.sax.SAXParseException;
030: import org.xml.sax.XMLReader;
031: import org.xml.sax.helpers.DefaultHandler;
032:
033: /**
034: * Contains the common implementation of a loader, for loading a configuration
035: * from an XML file.
036: * <p>
037: * The error handling policy can be described as being austere, dead set,
038: * disciplinary, dour, draconian, exacting, firm, forbidding, grim, hard, hard-
039: * boiled, harsh, harsh, in line, iron-fisted, no-nonsense, oppressive,
040: * persnickety, picky, prudish, punctilious, puritanical, rigid, rigorous,
041: * scrupulous, set, severe, square, stern, stickler, straight, strait-laced,
042: * stringent, stuffy, stuffy, tough, unpermissive, unsparing and uptight.
043: *
044: * @author Oliver Burn
045: */
046: public abstract class AbstractLoader extends DefaultHandler {
047: /** maps public id to resolve to esource name for the DTD */
048: private final Map mPublicIdToResourceNameMap;
049: /** parser to read XML files **/
050: private final XMLReader mParser;
051:
052: /**
053: * Creates a new instance.
054: * @param aPublicId the public ID for the DTD to resolve
055: * @param aDtdResourceName the resource for the DTD
056: * @throws SAXException if an error occurs
057: * @throws ParserConfigurationException if an error occurs
058: */
059: protected AbstractLoader(String aPublicId, String aDtdResourceName)
060: throws SAXException, ParserConfigurationException {
061: this (new HashMap(1));
062: mPublicIdToResourceNameMap.put(aPublicId, aDtdResourceName);
063: }
064:
065: /**
066: * Creates a new instance.
067: * @param aPublicIdToResourceNameMap maps public IDs to DTD resource names
068: * @throws SAXException if an error occurs
069: * @throws ParserConfigurationException if an error occurs
070: */
071: protected AbstractLoader(Map aPublicIdToResourceNameMap)
072: throws SAXException, ParserConfigurationException {
073: mPublicIdToResourceNameMap = new HashMap(
074: aPublicIdToResourceNameMap);
075: final SAXParserFactory factory = SAXParserFactory.newInstance();
076: factory.setValidating(true);
077: factory.setNamespaceAware(true);
078: mParser = factory.newSAXParser().getXMLReader();
079: mParser.setContentHandler(this );
080: mParser.setEntityResolver(this );
081: mParser.setErrorHandler(this );
082: }
083:
084: /**
085: * Parses the specified input source.
086: * @param aInputSource the input source to parse.
087: * @throws IOException if an error occurs
088: * @throws SAXException in an error occurs
089: */
090: public void parseInputSource(InputSource aInputSource)
091: throws IOException, SAXException {
092: mParser.parse(aInputSource);
093: }
094:
095: /** {@inheritDoc} */
096: public InputSource resolveEntity(String aPublicId, String aSystemId)
097: throws SAXException {
098: if (mPublicIdToResourceNameMap.keySet().contains(aPublicId)) {
099: final String dtdResourceName = (String) mPublicIdToResourceNameMap
100: .get(aPublicId);
101: final ClassLoader loader = Thread.currentThread()
102: .getContextClassLoader();
103: final InputStream dtdIS = loader
104: .getResourceAsStream(dtdResourceName);
105: if (dtdIS == null) {
106: throw new SAXException("Unable to load internal dtd "
107: + dtdResourceName);
108: }
109: return new InputSource(dtdIS);
110: }
111: // This is a hack to workaround problem with SAX
112: // DefaultHeader.resolveEntity():
113: // sometimes it throws SAX- and IO- exceptions
114: // sometime SAX only :(
115: try {
116: if (false) {
117: throw new IOException("");
118: }
119: return super .resolveEntity(aPublicId, aSystemId);
120: } catch (final IOException e) {
121: throw new SAXException("" + e, e);
122: }
123: }
124:
125: /** {@inheritDoc} */
126: public void warning(SAXParseException aEx) throws SAXException {
127: throw aEx;
128: }
129:
130: /** {@inheritDoc} */
131: public void error(SAXParseException aEx) throws SAXException {
132: throw aEx;
133: }
134:
135: /** {@inheritDoc} */
136: public void fatalError(SAXParseException aEx) throws SAXException {
137: throw aEx;
138: }
139: }
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