/**
* Copyright (C) 2010 Orbeon, Inc.
*
* 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
* 2.1 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.
*
* The full text of the license is available at http://www.gnu.org/copyleft/lesser.html
*/
package org.orbeon.oxf.processor.converter;
import org.orbeon.oxf.common.OXFException;
import org.orbeon.oxf.http.Headers;
import org.orbeon.oxf.pipeline.api.PipelineContext;
import org.orbeon.oxf.pipeline.api.TransformerXMLReceiver;
import org.orbeon.oxf.processor.BinaryTextSupport;
import org.orbeon.oxf.xml.XMLReceiver;
import org.orbeon.oxf.processor.ProcessorInput;
import org.orbeon.oxf.processor.ProcessorOutput;
import org.orbeon.oxf.processor.impl.CacheableTransformerOutputImpl;
import org.orbeon.oxf.processor.serializer.BinaryTextXMLReceiver;
import org.orbeon.oxf.util.ContentHandlerWriter;
import org.orbeon.oxf.xml.SimpleForwardingXMLReceiver;
import org.orbeon.oxf.xml.XMLConstants;
import org.xml.sax.Attributes;
import org.xml.sax.ContentHandler;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.AttributesImpl;
import javax.xml.transform.stream.StreamResult;
/**
* Base class for text converters.
*/
public abstract class TextConverterBase extends ConverterBase {
public static final String DEFAULT_METHOD_PROPERTY_NAME = "default-method";
/**
* This must be overridden by subclasses.
*
* @return true iif the method already
*/
protected abstract TransformerXMLReceiver createTransformer(Config config);
/**
* Return the namespace URI of the schema validating the config input. Can be overridden by
* subclasses.
*/
protected String getConfigSchemaNamespaceURI() {
return STANDARD_TEXT_CONVERTER_CONFIG_NAMESPACE_URI;
}
/**
* Perform the conversion.
*/
@Override
public ProcessorOutput createOutput(String name) {
if (!name.equals(OUTPUT_DATA))
throw new OXFException("Invalid output created: " + name);
final ProcessorOutput output = new CacheableTransformerOutputImpl(TextConverterBase.this, name) {
public void readImpl(PipelineContext pipelineContext, XMLReceiver xmlReceiver) {
// Read configuration input
final Config config = readConfig(pipelineContext);
final String encoding = getEncoding(config, DEFAULT_ENCODING);
final String contentType = getContentType(config, getDefaultContentType());
try {
// Start document
final AttributesImpl attributes = new AttributesImpl();
attributes.addAttribute(XMLConstants.XSI_URI, "type", "xsi:type", "CDATA", XMLConstants.XS_STRING_QNAME.getQualifiedName());
if (contentType != null)
attributes.addAttribute("", Headers.ContentTypeLower(), Headers.ContentTypeLower(), "CDATA", contentType + "; charset=" + encoding);
// Start document
xmlReceiver.startDocument();
xmlReceiver.startPrefixMapping(XMLConstants.XSI_PREFIX, XMLConstants.XSI_URI);
xmlReceiver.startPrefixMapping(XMLConstants.XSD_PREFIX, XMLConstants.XSD_URI);
xmlReceiver.startElement("", BinaryTextSupport.TextDocumentElementName(), BinaryTextSupport.TextDocumentElementName(), attributes);
// Create OutputStream that converts to Base64
final TransformerXMLReceiver transformer = createTransformer(config);
transformer.setResult(new StreamResult(new ContentHandlerWriter(xmlReceiver)));
// Write content
final boolean didEndDocument = readInput(pipelineContext, xmlReceiver, getInputByName(INPUT_DATA), transformer);
// End document if readInput() did not do it
// The reason we allow readInput() to do it directly is to help with streaming: upstream calls
// endDocument(), which in turn calls endDocument() downstream, instead of waiting until readInput()
// returns.
if (!didEndDocument)
sendEndDocument(xmlReceiver);
} catch (SAXException e) {
throw new OXFException(e);
}
}
};
addOutput(name, output);
return output;
}
private boolean readInput(PipelineContext context, final XMLReceiver downstreamReceiver, ProcessorInput input, final XMLReceiver transformer) {
final boolean[] didEndDocument = new boolean[1];
readInputAsSAX(context, input, createFilterReceiver(downstreamReceiver, transformer, didEndDocument));
return didEndDocument[0];
}
protected XMLReceiver createFilterReceiver(XMLReceiver downstreamReceiver, XMLReceiver transformer, boolean[] didEndDocument) {
return new FilterReceiver(downstreamReceiver, transformer, didEndDocument);
}
protected static class FilterReceiver extends SimpleForwardingXMLReceiver {
private final XMLReceiver downstreamReceiver;
private final boolean[] didEndDocument;
public FilterReceiver(XMLReceiver downstreamReceiver, XMLReceiver transformer, boolean[] didEndDocument) {
super(transformer);
this.downstreamReceiver = downstreamReceiver;
this.didEndDocument = didEndDocument;
}
private boolean seenRootElement = false;
@Override
public void processingInstruction(String target, String data) throws SAXException {
// Forward directly to the output any serializer processing instructions that took place before the root
// element. Note that this is a rather arbitrary choice! we could do any of the following:
//
// 1. Just let the transformer serialize the PI
// 2. Place serializer PIs as attributes the root element of the resulting <document> (e.g. <document status-code="404">)
// 3. Forward those PIs as we do here
//
// This could even be configurable. For now, we choose option #3 for ease of implementation.
if (seenRootElement || ! BinaryTextXMLReceiver.isSerializerPI(target, data))
super.processingInstruction(target, data);
else
downstreamReceiver.processingInstruction(target, data);
}
@Override
public void startElement(String uri, String localname, String qName, Attributes attributes) throws SAXException {
seenRootElement = true;
super.startElement(uri, localname, qName, attributes);
}
public void endDocument() throws SAXException {
super.endDocument();
sendEndDocument(downstreamReceiver);
didEndDocument[0] = true;
}
}
private static void sendEndDocument(ContentHandler contentHandler) {
try {
contentHandler.endElement("", BinaryTextSupport.TextDocumentElementName(), BinaryTextSupport.TextDocumentElementName());
contentHandler.endDocument();
} catch (SAXException e) {
throw new OXFException(e);
}
}
}