com.marklogic.client.io.XMLStreamReaderHandle 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.OutputStream;
import java.io.UnsupportedEncodingException;
import javax.xml.stream.FactoryConfigurationError;
import javax.xml.stream.XMLEventReader;
import javax.xml.stream.XMLEventWriter;
import javax.xml.stream.XMLInputFactory;
import javax.xml.stream.XMLOutputFactory;
import javax.xml.stream.XMLResolver;
import javax.xml.stream.XMLStreamException;
import javax.xml.stream.XMLStreamReader;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
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 XML Stream Reader Handle represents XML content as an XML stream reader
* for reading as a StAX pull stream.
*
* Either call {@link #close} or {@link #get}.close() when finished with this handle
* to release the resources.
*/
public class XMLStreamReaderHandle
extends BaseHandle
implements OutputStreamSender, BufferableHandle, ContentHandle,
XMLReadHandle, XMLWriteHandle,
StructureReadHandle, StructureWriteHandle,
Closeable
{
static final private Logger logger = LoggerFactory.getLogger(XMLStreamReaderHandle.class);
private XMLResolver resolver;
private XMLStreamReader content;
private InputStream contentSource;
private XMLInputFactory factory;
/**
* Creates a factory to create an XMLStreamReaderHandle instance for a StAX stream reader.
* @return the factory
*/
static public ContentHandleFactory newFactory() {
return new ContentHandleFactory() {
@Override
public Class[] getHandledClasses() {
return new Class[]{ XMLStreamReader.class };
}
@Override
public boolean isHandled(Class type) {
return XMLStreamReader.class.isAssignableFrom(type);
}
@Override
public ContentHandle newHandle(Class type) {
@SuppressWarnings("unchecked")
ContentHandle handle = isHandled(type) ?
(ContentHandle) new XMLStreamReaderHandle() : null;
return handle;
}
};
}
/**
* Zero-argument constructor.
*/
public XMLStreamReaderHandle() {
super();
super.setFormat(Format.XML);
setResendable(false);
}
/**
* Initializes the handle with a StAX stream reader for the content.
* @param content a StAX stream reader
*/
public XMLStreamReaderHandle(XMLStreamReader content) {
this();
set(content);
}
/**
* Returns the resolver for resolving references while parsing
* the event reader source.
* @return the resolver
*/
public XMLResolver getResolver() {
return resolver;
}
/**
* Specifies the resolver for resolving references while parsing
* the event reader source.
* @param resolver the reference resolver
*/
public void setResolver(XMLResolver resolver) {
this.resolver = resolver;
}
/**
* Returns an XML Stream Reader for for reading a resource from the database
* as a StAX pull stream.
*
* When finished with the stream reader, call {@link #close} to release
* the response.
*
* @return the XML stream reader
*/
@Override
public XMLStreamReader get() {
return content;
}
/**
* Assigns the stream reader for the content.
* @param content a StAX stream reader
*/
@Override
public void set(XMLStreamReader content) {
this.content = content;
}
/**
* Assigns an stream reader for the content and returns the handle
* as a fluent convenience.
* @param content a StAX stream reader
* @return this handle
*/
public XMLStreamReaderHandle with(XMLStreamReader content) {
set(content);
return this;
}
/**
* Restricts the format to XML.
*/
public void setFormat(Format format) {
if (format != Format.XML)
throw new IllegalArgumentException("XMLStreamReaderHandle 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 XMLStreamReaderHandle 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);
}
}
/**
* Closes the XMLStreamReader and the InputStream, if any, used to populate
* the XMLStreamReader. This method or get().close() should always be called when finished
* with the stream reader.
*/
public void close() {
try {
if ( content != null ) content.close();
} catch (XMLStreamException e) {
logger.error("Failed to close underlying XMLStreamReader",e);
throw new MarkLogicIOException(e);
// whether that failed or not, attempt to close underlying InputStream
} finally {
if ( contentSource != null ) {
try {
contentSource.close();
} catch (IOException e) {
logger.error("Failed to close underlying InputStream",e);
throw new MarkLogicIOException(e);
}
}
}
}
/**
* Buffers the StAX stream 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 StAX streams.
* @return the StAX factory
*/
public XMLInputFactory getFactory() {
if (factory == null)
factory = makeXMLInputFactory();
return factory;
}
/**
* Specifies the factory for parsing StAX streams.
* @param factory the StAX factory
*/
public void setFactory(XMLInputFactory factory) {
this.factory = factory;
}
protected XMLInputFactory makeXMLInputFactory() {
XMLInputFactory factory = XMLInputFactory.newFactory();
factory.setProperty("javax.xml.stream.isNamespaceAware", true);
factory.setProperty("javax.xml.stream.isValidating", false);
return factory;
}
@Override
protected Class receiveAs() {
return InputStream.class;
}
@Override
protected void receiveContent(InputStream content) {
if (content == null) {
this.content = null;
return;
}
try {
if (logger.isInfoEnabled())
logger.info("Parsing StAX stream from input stream");
XMLInputFactory factory = getFactory();
if (factory == null) {
throw new MarkLogicInternalException("Failed to make StAX input factory");
}
if (resolver != null)
factory.setXMLResolver(resolver);
this.content = factory.createXMLStreamReader(content, "UTF-8");
this.contentSource = content;
} catch (XMLStreamException e) {
logger.error("Failed to parse StAX stream from input stream",e);
throw new MarkLogicInternalException(e);
} catch (FactoryConfigurationError e) {
logger.error("Failed to parse StAX stream from input stream",e);
throw new MarkLogicInternalException(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 {
XMLInputFactory inputFactory = getFactory();
if (inputFactory == null) {
throw new MarkLogicInternalException("Failed to make StAX input factory");
}
// TODO: rework to copy straight from stream reader to stream writer
XMLEventReader reader = inputFactory.createXMLEventReader(content);
XMLOutputFactory outputFactory = XMLOutputFactory.newFactory();
XMLEventWriter writer =
outputFactory.createXMLEventWriter(out, "UTF-8");
writer.add(reader);
writer.flush();
writer.close();
content.close();
} catch (XMLStreamException e) {
logger.error("Failed to parse StAX events from input stream",e);
throw new MarkLogicInternalException(e);
}
}
}