/*
* eXist Open Source Native XML Database
* Copyright (C) 2007-2010 The eXist Project
* http://exist-db.org
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
package org.exist.xquery.modules.exi;
import java.io.IOException;
import java.io.InputStream;
import org.exist.dom.QName;
import org.exist.memtree.AppendingSAXAdapter;
import org.exist.memtree.MemTreeBuilder;
import org.exist.memtree.SAXAdapter;
import org.exist.xquery.BasicFunction;
import org.exist.xquery.Cardinality;
import org.exist.xquery.ErrorCodes.JavaErrorCode;
import org.exist.xquery.FunctionSignature;
import org.exist.xquery.XPathException;
import org.exist.xquery.XQueryContext;
import org.exist.xquery.value.BinaryValue;
import org.exist.xquery.value.FunctionParameterSequenceType;
import org.exist.xquery.value.FunctionReturnSequenceType;
import org.exist.xquery.value.Item;
import org.exist.xquery.value.NodeValue;
import org.exist.xquery.value.Sequence;
import org.exist.xquery.value.SequenceType;
import org.exist.xquery.value.Type;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
import com.siemens.ct.exi.EXIFactory;
import com.siemens.ct.exi.GrammarFactory;
import com.siemens.ct.exi.api.sax.SAXDecoder;
import com.siemens.ct.exi.exceptions.EXIException;
import com.siemens.ct.exi.grammar.Grammar;
import com.siemens.ct.exi.helpers.DefaultEXIFactory;
/**
* eXist EXI Module Extension DecodeExiFunction.
*
* Decodes an Efficient XML Interchange (EXI) source to XML.
*
* @author Rob Walpole
* @version 1.0
*
*/
public class DecodeExiFunction extends BasicFunction {
public final static FunctionSignature[] signatures = {
new FunctionSignature(
new QName("decode-to-xml", ExiModule.NAMESPACE_URI, ExiModule.PREFIX),
"A function which returns XML from a decoded EXI source",
new SequenceType[] {
new FunctionParameterSequenceType("source-exi", Type.BASE64_BINARY, Cardinality.EXACTLY_ONE, "the EXI source")},
new FunctionReturnSequenceType(Type.NODE, Cardinality.ZERO_OR_ONE, "the XML result")
),
new FunctionSignature(
new QName("decode-to-xml", ExiModule.NAMESPACE_URI, ExiModule.PREFIX),
"A function which return XML from a schema decoded EXI source",
new SequenceType[] {
new FunctionParameterSequenceType("source-exi", Type.BASE64_BINARY, Cardinality.EXACTLY_ONE, "the EXI source"),
new FunctionParameterSequenceType("schema-location", Type.ITEM, Cardinality.EXACTLY_ONE, "the XSD schema location")
},
new FunctionReturnSequenceType(Type.NODE, Cardinality.ZERO_OR_ONE, "the XML result")
)
};
public DecodeExiFunction(XQueryContext context, FunctionSignature signature) {
super(context, signature);
}
@Override
public Sequence eval(Sequence[] args, Sequence contextSequence)
throws XPathException {
if(args[0].isEmpty()) {
return Sequence.EMPTY_SEQUENCE;
}
try {
BinaryValue exiBinary = ((BinaryValue)args[0].itemAt(0));
MemTreeBuilder builder = context.getDocumentBuilder();
// create default factory and EXI grammar for schema
EXIFactory exiFactory = DefaultEXIFactory.newInstance();
if(args.length > 1) {
if(!args[1].isEmpty()) {
Item xsdItem = args[1].itemAt(0);
InputStream xsdInputStream = EXIUtils.getInputStream(xsdItem, context);
GrammarFactory grammarFactory = GrammarFactory.newInstance();
Grammar grammar = grammarFactory.createGrammar(xsdInputStream);
exiFactory.setGrammar(grammar);
}
}
SAXDecoder decoder = new SAXDecoder(exiFactory);
SAXAdapter adapter = new AppendingSAXAdapter(builder);
decoder.setContentHandler(adapter);
decoder.parse(new InputSource(exiBinary.getInputStream()));
NodeValue node = (NodeValue)builder.getDocument().getDocumentElement();
return node;
}
catch(EXIException exie) {
throw new XPathException(this, new JavaErrorCode(exie.getCause()), exie.getMessage());
}
catch(SAXException saxe) {
throw new XPathException(this, new JavaErrorCode(saxe.getCause()), saxe.getMessage());
}
catch(IOException ioex) {
throw new XPathException(this, new JavaErrorCode(ioex.getCause()), ioex.getMessage());
}
}
}