001 //$HeadURL: svn+ssh://jwilden@svn.wald.intevation.org/deegree/base/branches/2.5_testing/src/org/deegree/portal/context/ContextTransformer.java $
002 /*----------------------------------------------------------------------------
003 This file is part of deegree, http://deegree.org/
004 Copyright (C) 2001-2009 by:
005 Department of Geography, University of Bonn
006 and
007 lat/lon GmbH
008
009 This library is free software; you can redistribute it and/or modify it under
010 the terms of the GNU Lesser General Public License as published by the Free
011 Software Foundation; either version 2.1 of the License, or (at your option)
012 any later version.
013 This library is distributed in the hope that it will be useful, but WITHOUT
014 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
015 FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
016 details.
017 You should have received a copy of the GNU Lesser General Public License
018 along with this library; if not, write to the Free Software Foundation, Inc.,
019 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
020
021 Contact information:
022
023 lat/lon GmbH
024 Aennchenstr. 19, 53177 Bonn
025 Germany
026 http://lat-lon.de/
027
028 Department of Geography, University of Bonn
029 Prof. Dr. Klaus Greve
030 Postfach 1147, 53001 Bonn
031 Germany
032 http://www.geographie.uni-bonn.de/deegree/
033
034 e-mail: info@deegree.org
035 ----------------------------------------------------------------------------*/
036
037 package org.deegree.portal.context;
038
039 import java.io.IOException;
040 import java.io.InputStream;
041 import java.io.StringWriter;
042
043 import javax.xml.transform.Transformer;
044 import javax.xml.transform.TransformerConfigurationException;
045 import javax.xml.transform.TransformerException;
046 import javax.xml.transform.TransformerFactory;
047 import javax.xml.transform.TransformerFactoryConfigurationError;
048 import javax.xml.transform.stream.StreamResult;
049 import javax.xml.transform.stream.StreamSource;
050
051 import org.deegree.framework.log.ILogger;
052 import org.deegree.framework.log.LoggerFactory;
053
054 /**
055 * Singleton class capsulating a <code>javax.xml.transform.Transformer</code>. This class is used
056 * to transform a map context xml document in a html document used the transformation (xslt)
057 * provided.
058 *
059 * @author <a href="mailto:taddei@lat-lon.de">Ugo Taddei</a>
060 *
061 */
062 public class ContextTransformer {
063
064 private static final ILogger LOG = LoggerFactory.getLogger( ContextTransformer.class );
065
066 /**
067 * The <code>Transformer</code> object used in the transformation of a map context xml to
068 * html.
069 */
070 protected static Transformer transformer = null;
071
072 private static final ContextTransformer INSTANCE = new ContextTransformer();
073
074
075 private ContextTransformer() {
076 // Forbid instantiation
077 }
078
079 private static void initTransformer( InputStream is ) {
080
081 try {
082 TransformerFactory tFactory = TransformerFactory.newInstance();
083 transformer = tFactory.newTransformer( new StreamSource( is ) );
084 } catch ( TransformerConfigurationException e ) {
085 e.printStackTrace();
086 } catch ( TransformerFactoryConfigurationError e ) {
087 e.printStackTrace();
088 }
089 }
090
091 /**
092 * @return the singleton.
093 */
094 public static ContextTransformer getInstance() {
095 return INSTANCE;
096 }
097
098 /**
099 * Transforms the context pointed to by <code>context</code> into html using
100 * <code>xsltURL</code> (though this is currently fixed; there's really no need to define
101 * one's wn xsl).
102 *
103 * @param xsl
104 * the <code>InputStream</code> containing the xls
105 * @param contxt
106 * the <code>InputStream</code> containing the context to be transformed
107 * @return the converted string.
108 * @throws TransformerException
109 */
110 public String transformContext( InputStream xsl, InputStream contxt )
111 throws TransformerException {
112
113 StringWriter sw = new StringWriter();
114
115 if ( transformer == null ) { // needs to instantiate transformer
116 initTransformer( xsl );
117 }
118 if ( transformer == null ) {
119 LOG.logInfo( "transformer is still null" );
120 }
121 StreamResult sr = new StreamResult( sw );
122 StreamSource sSrc = new StreamSource( contxt );
123 transformer.transform( sSrc, sr );
124
125 try {
126 sw.close();
127 } catch ( IOException e ) {
128 LOG.logError( "Unable to close string writer.", e );
129 }
130
131 return sw.toString();
132 }
133
134 @Override
135 public String toString() {
136 return transformer.toString();
137 }
138 }