001 //$HeadURL: svn+ssh://rbezema@svn.wald.intevation.org/deegree/base/branches/2.2_testing/src/org/deegree/portal/context/ContextTransformer.java $
002 /*---------------- FILE HEADER ------------------------------------------
003
004 This file is part of deegree.
005 Copyright (C) 2001-2008 by:
006 EXSE, Department of Geography, University of Bonn
007 http://www.giub.uni-bonn.de/deegree/
008 lat/lon GmbH
009 http://www.lat-lon.de
010
011 This library is free software; you can redistribute it and/or
012 modify it under the terms of the GNU Lesser General Public
013 License as published by the Free Software Foundation; either
014 version 2.1 of the License, or (at your option) any later version.
015
016 This library is distributed in the hope that it will be useful,
017 but WITHOUT ANY WARRANTY; without even the implied warranty of
018 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
019 Lesser General Public License for more details.
020
021 You should have received a copy of the GNU Lesser General Public
022 License along with this library; if not, write to the Free Software
023 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
024
025 Contact:
026
027 Andreas Poth
028 lat/lon GmbH
029 Aennchenstr. 19
030 53115 Bonn
031 Germany
032 E-Mail: poth@lat-lon.de
033
034 Prof. Dr. Klaus Greve
035 Department of Geography
036 University of Bonn
037 Meckenheimer Allee 166
038 53115 Bonn
039 Germany
040 E-Mail: greve@giub.uni-bonn.de
041
042
043 ---------------------------------------------------------------------------*/
044
045 package org.deegree.portal.context;
046
047 import java.io.IOException;
048 import java.io.InputStream;
049 import java.io.StringWriter;
050
051 import javax.xml.transform.Transformer;
052 import javax.xml.transform.TransformerConfigurationException;
053 import javax.xml.transform.TransformerException;
054 import javax.xml.transform.TransformerFactory;
055 import javax.xml.transform.TransformerFactoryConfigurationError;
056 import javax.xml.transform.stream.StreamResult;
057 import javax.xml.transform.stream.StreamSource;
058
059 import org.deegree.framework.log.ILogger;
060 import org.deegree.framework.log.LoggerFactory;
061
062
063 /**
064 * Singleton class capsulating a <code>javax.xml.transform.Transformer</code>.
065 * This class is used to transform a map context xml document in a html
066 * document used the transformation (xslt) provided.
067 *
068 * @author <a href="mailto:taddei@lat-lon.de">Ugo Taddei</a>
069 *
070 */
071 public class ContextTransformer {
072
073 private static final ILogger LOG = LoggerFactory.getLogger( ContextTransformer.class );
074
075 /**
076 * The <code>Transformer</code> object used in the transformation of
077 * a map context xml to html.*/
078 protected static Transformer transformer = null;
079 private static final ContextTransformer INSTANCE = new ContextTransformer();
080
081 // Forbid instanstiation
082 private ContextTransformer() { }
083
084 private static void initTransformer(InputStream is){
085
086 try {
087 TransformerFactory tFactory = TransformerFactory.newInstance();
088 transformer = tFactory.newTransformer(
089 new StreamSource( is ) );
090 } catch (TransformerConfigurationException e) {
091 e.printStackTrace();
092 } catch (TransformerFactoryConfigurationError e) {
093 e.printStackTrace();
094 }
095 }
096
097 public static ContextTransformer getInstance(){
098
099 return INSTANCE;
100 }
101
102 /**
103 * Transforms the context pointed to by <code>context</code> into html
104 * using <code>xsltURL</code> (though this is currently fixed; there's
105 * really no need to define one's wn xsl).
106 * @param xsl the <code>InputStream</code> containing the xls
107 * @param contxt the <code>InputStream</code> containing the context to be transformed
108 */
109 public String transformContext( InputStream xsl, InputStream contxt)
110 throws TransformerException {
111
112 StringWriter sw = new StringWriter();
113
114 if( transformer == null ){ // needs to instatiate transformer
115 initTransformer(xsl);
116 }
117 if( transformer == null ){
118 LOG.logInfo( "transformer is still null" );
119 }
120 StreamResult sr = new StreamResult(sw);
121 StreamSource sSrc = new StreamSource( contxt );
122 transformer.transform( sSrc , sr );
123
124 try {
125 sw.close();
126 } catch (IOException e) {
127 LOG.logError( "Unable to close string writer.", e );
128 }
129
130 return sw.toString();
131 }
132
133 /**
134 *
135 */
136 public String toString(){
137 return transformer.toString();
138 }
139 }