com.marklogic.client.io.InputSourceHandle Maven / Gradle / Ivy
/*
* Copyright 2012-2016 MarkLogic Corporation
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.marklogic.client.io;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.Closeable;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.UnsupportedEncodingException;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.parsers.SAXParserFactory;
import javax.xml.transform.TransformerException;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.sax.SAXSource;
import javax.xml.transform.stream.StreamResult;
import javax.xml.validation.Schema;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.xml.sax.ContentHandler;
import org.xml.sax.EntityResolver;
import org.xml.sax.ErrorHandler;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
import org.xml.sax.SAXParseException;
import org.xml.sax.XMLReader;
import com.marklogic.client.MarkLogicIOException;
import com.marklogic.client.MarkLogicInternalException;
import com.marklogic.client.io.marker.BufferableHandle;
import com.marklogic.client.io.marker.ContentHandle;
import com.marklogic.client.io.marker.ContentHandleFactory;
import com.marklogic.client.io.marker.StructureReadHandle;
import com.marklogic.client.io.marker.StructureWriteHandle;
import com.marklogic.client.io.marker.XMLReadHandle;
import com.marklogic.client.io.marker.XMLWriteHandle;
/**
* An Input Source Handle represents XML content as an input source for reading or writing.
* When reading, the XML may be processed by a SAX content handler.
*
* Always call {@link #close} when finished with this handle to release the resources.
*/
public class InputSourceHandle
extends BaseHandle
implements OutputStreamSender, BufferableHandle, ContentHandle,
XMLReadHandle, XMLWriteHandle,
StructureReadHandle, StructureWriteHandle,
Closeable
{
static final private Logger logger = LoggerFactory.getLogger(InputSourceHandle.class);
private EntityResolver resolver;
private ErrorHandler errorHandler;
private Schema defaultWriteSchema;
private SAXParserFactory factory;
private InputSource content;
private InputStream underlyingStream;
/**
* Creates a factory to create a InputSourceHandle instance for a SAX InputSource.
* @return the factory
*/
static public ContentHandleFactory newFactory() {
return new ContentHandleFactory() {
@Override
public Class[] getHandledClasses() {
return new Class[]{ InputSource.class };
}
@Override
public boolean isHandled(Class type) {
return InputSource.class.isAssignableFrom(type);
}
@Override
public ContentHandle newHandle(Class type) {
@SuppressWarnings("unchecked")
ContentHandle handle = isHandled(type) ?
(ContentHandle) new InputSourceHandle() : null;
return handle;
}
};
}
/**
* Zero-argument constructor.
*/
public InputSourceHandle() {
super();
super.setFormat(Format.XML);
setResendable(false);
}
/**
* Initializes the handle with a SAX input source for the content.
* @param content a SAX input source
*/
public InputSourceHandle(InputSource content) {
this();
set(content);
}
/**
* Returns the resolver for resolving references while parsing
* the input source.
* @return the resolver
*/
public EntityResolver getResolver() {
return resolver;
}
/**
* Specifies the resolver for resolving references while parsing
* the input source.
* @param resolver the reference resolver
*/
public void setResolver(EntityResolver resolver) {
this.resolver = resolver;
}
/**
* Returns the error handler for errors discovered while parsing
* the input source.
* @return the error handler
*/
public ErrorHandler getErrorHandler() {
return errorHandler;
}
/**
* Specifies the error handler for errors discovered while parsing
* the input source.
* @param errorHandler the error handler
*/
public void setErrorHandler(ErrorHandler errorHandler) {
this.errorHandler = errorHandler;
}
/**
* Returns the input source for the content.
* @return the input source
*/
@Override
public InputSource get() {
return content;
}
/**
* Assigns an input source as the content.
* @param content an input source
*/
@Override
public void set(InputSource content) {
this.content = content;
}
/**
* Assigns an input source as the content and returns the handle
* as a fluent convenience.
* @param content an input source
* @return this handle
*/
public InputSourceHandle with(InputSource content) {
set(content);
return this;
}
/**
* Reads the input source, sending SAX events to the supplied content handler.
* @param handler the SAX content handler
*/
public void process(ContentHandler handler) {
try {
if (logger.isInfoEnabled())
logger.info("Processing input source with SAX content handler");
XMLReader reader = makeReader(false);
reader.setContentHandler(handler);
reader.parse(content);
} catch (SAXException e) {
logger.error("Failed to process input source with SAX content handler",e);
throw new MarkLogicInternalException(e);
} catch (IOException e) {
logger.error("Failed to process input source with SAX content handler",e);
throw new MarkLogicInternalException(e);
}
}
/**
* Restricts the format to XML.
*/
@Override
public void setFormat(Format format) {
if (format != Format.XML)
throw new IllegalArgumentException("InputSourceHandle supports the XML format only");
}
/**
* Specifies the mime type of the content and returns the handle
* as a fluent convenience.
* @param mimetype the mime type of the content
* @return this handle
*/
public InputSourceHandle withMimetype(String mimetype) {
setMimetype(mimetype);
return this;
}
@Override
public void fromBuffer(byte[] buffer) {
if (buffer == null || buffer.length == 0)
content = null;
else
receiveContent(new ByteArrayInputStream(buffer));
}
@Override
public byte[] toBuffer() {
try {
if (content == null)
return null;
ByteArrayOutputStream buffer = new ByteArrayOutputStream();
write(buffer);
byte[] b = buffer.toByteArray();
fromBuffer(b);
return b;
} catch (IOException e) {
throw new MarkLogicIOException(e);
}
}
/**
* Buffers the SAX input source and returns the buffer
* as an XML string.
*/
@Override
public String toString() {
try {
return new String(toBuffer(),"UTF-8");
} catch (UnsupportedEncodingException e) {
throw new MarkLogicIOException(e);
}
}
/**
* Returns the factory for parsing SAX events.
* @return the SAX factory
* @throws SAXException if such an error occurs while initializing the
* new factory
* @throws ParserConfigurationException if such an error occurs while
* initializing the new factory
*/
public SAXParserFactory getFactory() throws SAXException, ParserConfigurationException {
if (factory == null)
factory = makeSAXParserFactory();
return factory;
}
/**
* Specifies the factory for parsing SAX events.
* @param factory the SAX factory
*/
public void setFactory(SAXParserFactory factory) {
this.factory = factory;
}
protected SAXParserFactory makeSAXParserFactory() throws SAXException, ParserConfigurationException {
SAXParserFactory factory = SAXParserFactory.newInstance();
factory.setNamespaceAware(true);
factory.setValidating(false);
// TODO: XInclude
return factory;
}
/**
* Returns the default schema for validating the input source
* while writing to the database.
* @return the default schema for writing documents
*/
public Schema getDefaultWriteSchema() {
return defaultWriteSchema;
}
/**
* Specifies the default schema for validating the input source. The
* default schema is used only while writing to the database and only
* when no schema has been set directly on the factory. To minimize
* creation of partial documents while writing an input source to the database,
* set the error handler on the InputSourceHandle to {@link DraconianErrorHandler}
* and set the repair policy to NONE on the XMLDocumentManager. An error on the
* root element can still result in an empty document.
* @param schema the default schema for writing documents
*/
public void setDefaultWriteSchema(Schema schema) {
this.defaultWriteSchema = schema;
}
protected XMLReader makeReader(boolean isForWrite) {
try {
SAXParserFactory factory = getFactory();
if (factory == null) {
throw new MarkLogicInternalException("Failed to make SAX parser factory");
}
boolean useDefaultSchema =
(isForWrite && defaultWriteSchema != null && factory.getSchema() == null);
if (useDefaultSchema) {
factory.setSchema(defaultWriteSchema);
}
XMLReader reader = factory.newSAXParser().getXMLReader();
if (useDefaultSchema) {
factory.setSchema(null);
}
if (resolver != null)
reader.setEntityResolver(resolver);
if (errorHandler != null)
reader.setErrorHandler(errorHandler);
return reader;
} catch (SAXException e) {
logger.error("Failed to process input source with SAX content handler",e);
throw new MarkLogicInternalException(e);
} catch (ParserConfigurationException e) {
logger.error("Failed to process input source with SAX content handler",e);
throw new MarkLogicInternalException(e);
}
}
@Override
protected Class receiveAs() {
return InputStream.class;
}
@Override
protected void receiveContent(InputStream content) {
try {
if (content == null) {
this.content = null;
return;
}
this.underlyingStream = content;
this.content = new InputSource(new InputStreamReader(content, "UTF-8"));
} catch (UnsupportedEncodingException e) {
logger.error("Failed to read input stream as input source",e);
throw new MarkLogicIOException(e);
}
}
@Override
protected OutputStreamSender sendContent() {
if (content == null) {
throw new IllegalStateException("No input source to write");
}
return this;
}
@Override
public void write(OutputStream out) throws IOException {
try {
TransformerFactory.newInstance().newTransformer().transform(
new SAXSource(makeReader(true), content),
new StreamResult(new OutputStreamWriter(out, "UTF-8"))
);
} catch (TransformerException e) {
logger.error("Failed to transform input source into result",e);
throw new MarkLogicIOException(e);
}
}
/**
* DraconianErrorHandler treats SAX parse errors as exceptions
* but ignores warnings (based on the JavaDoc for the
* javax.xml.validation package). To minimize creation of partial
* documents while writing an input source to the database,
* set the error handler on the InputSourceHandle to DraconianErrorHandler
* and set the repair policy to NONE on the XMLDocumentManager. An error
* on the root element can still result in an empty document.
*/
static public class DraconianErrorHandler implements ErrorHandler {
/**
* Throws the fatal error as a parse exception.
*/
@Override
public void fatalError(SAXParseException e) throws SAXException {
throw e;
}
/**
* Throws the error as a parse exception.
*/
@Override
public void error(SAXParseException e) throws SAXException {
throw e;
}
/**
* Ignores the warning.
*/
@Override
public void warning(SAXParseException e) throws SAXException {
// noop
}
}
/** Always call close() when finished with this handle -- it closes the underlying InputStream.
*/
public void close() {
if ( underlyingStream != null ) {
try {
underlyingStream.close();
} catch (IOException e) {
logger.error("Failed to close underlying InputStream",e);
throw new MarkLogicIOException(e);
}
}
}
}