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Copyright 2010, Google Inc.
All rights reserved.
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modification, are permitted provided that the following conditions are
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* Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
* Redistributions in binary form must reproduce the above
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in the documentation and/or other materials provided with the
distribution.
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contributors may be used to endorse or promote products derived from
this software without specific prior written permission.
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"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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package com.google.refine.importers;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PushbackInputStream;
import java.io.Serializable;
import java.util.List;
import javax.xml.stream.XMLInputFactory;
import javax.xml.stream.XMLStreamConstants;
import javax.xml.stream.XMLStreamException;
import javax.xml.stream.XMLStreamReader;
import org.json.JSONArray;
import org.json.JSONObject;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import com.google.refine.ProjectMetadata;
import com.google.refine.importers.tree.ImportColumnGroup;
import com.google.refine.importers.tree.TreeImportingParserBase;
import com.google.refine.importers.tree.TreeReader;
import com.google.refine.importers.tree.TreeReaderException;
import com.google.refine.importing.ImportingJob;
import com.google.refine.importing.ImportingUtilities;
import com.google.refine.model.Project;
import com.google.refine.util.JSONUtilities;
public class XmlImporter extends TreeImportingParserBase {
static final Logger logger = LoggerFactory.getLogger(XmlImporter.class);
public XmlImporter() {
super(true);
}
static private class PreviewParsingState {
int tokenCount;
}
final static private int PREVIEW_PARSING_LIMIT = 1000;
@Override
public JSONObject createParserUIInitializationData(
ImportingJob job, List<JSONObject> fileRecords, String format) {
JSONObject options = super.createParserUIInitializationData(job, fileRecords, format);
try {
if (fileRecords.size() > 0) {
JSONObject firstFileRecord = fileRecords.get(0);
File file = ImportingUtilities.getFile(job, firstFileRecord);
InputStream is = new FileInputStream(file);
try {
XMLStreamReader parser = createXMLStreamReader(is);
PreviewParsingState state = new PreviewParsingState();
while (parser.hasNext() && state.tokenCount < PREVIEW_PARSING_LIMIT) {
int tokenType = parser.next();
state.tokenCount++;
if (tokenType == XMLStreamConstants.START_ELEMENT) {
JSONObject rootElement = descendElement(parser, state);
if (rootElement != null) {
JSONUtilities.safePut(options, "dom", rootElement);
break;
}
} else {
// ignore everything else
}
}
} catch (XMLStreamException e) {
logger.warn("Error generating parser UI initialization data for XML file", e);
} finally {
is.close();
}
}
} catch (IOException e) {
logger.error("Error generating parser UI initialization data for XML file", e);
}
return options;
}
final static private JSONObject descendElement(XMLStreamReader parser, PreviewParsingState state) {
JSONObject result = new JSONObject();
{
String name = parser.getLocalName();
JSONUtilities.safePut(result, "n", name);
String prefix = parser.getPrefix();
if (prefix != null) {
JSONUtilities.safePut(result, "p", prefix);
}
String nsUri = parser.getNamespaceURI();
if (nsUri != null) {
JSONUtilities.safePut(result, "uri", nsUri);
}
}
int namespaceCount = parser.getNamespaceCount();
if (namespaceCount > 0) {
JSONArray namespaces = new JSONArray();
JSONUtilities.safePut(result, "ns", namespaces);
for (int i = 0; i < namespaceCount; i++) {
JSONObject namespace = new JSONObject();
JSONUtilities.append(namespaces, namespace);
JSONUtilities.safePut(namespace, "p", parser.getNamespacePrefix(i));
JSONUtilities.safePut(namespace, "uri", parser.getNamespaceURI(i));
}
}
int attributeCount = parser.getAttributeCount();
if (attributeCount > 0) {
JSONArray attributes = new JSONArray();
JSONUtilities.safePut(result, "a", attributes);
for (int i = 0; i < attributeCount; i++) {
JSONObject attribute = new JSONObject();
JSONUtilities.append(attributes, attribute);
JSONUtilities.safePut(attribute, "n", parser.getAttributeLocalName(i));
JSONUtilities.safePut(attribute, "v", parser.getAttributeValue(i));
String prefix = parser.getAttributePrefix(i);
if (prefix != null) {
JSONUtilities.safePut(attribute, "p", prefix);
}
}
}
JSONArray children = new JSONArray();
try {
while (parser.hasNext() && state.tokenCount < PREVIEW_PARSING_LIMIT) {
int tokenType = parser.next();
state.tokenCount++;
if (tokenType == XMLStreamConstants.END_ELEMENT) {
break;
} else if (tokenType == XMLStreamConstants.START_ELEMENT) {
JSONObject childElement = descendElement(parser, state);
if (childElement != null) {
JSONUtilities.append(children, childElement);
}
} else if (tokenType == XMLStreamConstants.CHARACTERS ||
tokenType == XMLStreamConstants.CDATA ||
tokenType == XMLStreamConstants.SPACE) {
JSONObject childElement = new JSONObject();
JSONUtilities.safePut(childElement, "t", parser.getText());
JSONUtilities.append(children, childElement);
} else {
// ignore everything else
}
}
} catch (XMLStreamException e) {
logger.error("Error generating parser UI initialization data for XML file", e);
}
if (children.length() > 0) {
JSONUtilities.safePut(result, "c", children);
}
return result;
}
@Override
public void parseOneFile(Project project, ProjectMetadata metadata,
ImportingJob job, String fileSource, InputStream inputStream,
ImportColumnGroup rootColumnGroup, int limit, JSONObject options,
List<Exception> exceptions) {
try {
parseOneFile(project, metadata, job, fileSource,
new XmlParser(inputStream), rootColumnGroup, limit, options, exceptions);
} catch (XMLStreamException e) {
exceptions.add(e);
} catch (IOException e) {
exceptions.add(e);
}
}
static public class XmlParser implements TreeReader {
final protected XMLStreamReader parser;
public XmlParser(InputStream inputStream) throws XMLStreamException, IOException {
parser = createXMLStreamReader(inputStream);
}
@Override
public Token next() throws TreeReaderException {
try {
if (!parser.hasNext()) {
throw new TreeReaderException("End of XML stream");
}
} catch (XMLStreamException e) {
throw new TreeReaderException(e);
}
int currentToken = -1;
try {
currentToken = parser.next();
} catch (XMLStreamException e) {
throw new TreeReaderException(e);
}
return mapToToken(currentToken);
}
protected Token mapToToken(int token) {
switch(token){
case XMLStreamConstants.START_ELEMENT: return Token.StartEntity;
case XMLStreamConstants.END_ELEMENT: return Token.EndEntity;
case XMLStreamConstants.CHARACTERS: return Token.Value;
case XMLStreamConstants.START_DOCUMENT: return Token.Ignorable;
case XMLStreamConstants.END_DOCUMENT: return Token.Ignorable;
case XMLStreamConstants.SPACE: return Token.Value;
case XMLStreamConstants.PROCESSING_INSTRUCTION: return Token.Ignorable;
case XMLStreamConstants.NOTATION_DECLARATION: return Token.Ignorable;
case XMLStreamConstants.NAMESPACE: return Token.Ignorable;
case XMLStreamConstants.ENTITY_REFERENCE: return Token.Ignorable;
case XMLStreamConstants.DTD: return Token.Ignorable;
case XMLStreamConstants.COMMENT: return Token.Ignorable;
case XMLStreamConstants.CDATA: return Token.Ignorable;
case XMLStreamConstants.ATTRIBUTE: return Token.Ignorable;
default:
return Token.Ignorable;
}
}
@Override
public Token current() throws TreeReaderException {
return this.mapToToken(parser.getEventType());
}
@Override
public boolean hasNext() throws TreeReaderException {
try {
return parser.hasNext();
} catch (XMLStreamException e) {
throw new TreeReaderException(e);
}
}
@Override
public String getFieldName() throws TreeReaderException {
try {
return parser.getLocalName();
} catch (IllegalStateException e) {
return null;
}
}
@Override
public String getPrefix(){
return parser.getPrefix();
}
@Override
public String getFieldValue(){
return parser.getText();
}
@Override
public Serializable getValue() {
// XML parser only does string types
return getFieldValue();
}
@Override
public int getAttributeCount(){
return parser.getAttributeCount();
}
@Override
public String getAttributeValue(int index){
return parser.getAttributeValue(index);
}
@Override
public String getAttributePrefix(int index){
return parser.getAttributePrefix(index);
}
@Override
public String getAttributeLocalName(int index){
return parser.getAttributeLocalName(index);
}
}
final static private XMLStreamReader createXMLStreamReader(InputStream inputStream) throws XMLStreamException, IOException {
XMLInputFactory factory = XMLInputFactory.newInstance();
factory.setProperty(XMLInputFactory.IS_COALESCING, true);
factory.setProperty(XMLInputFactory.IS_REPLACING_ENTITY_REFERENCES, true);
return factory.createXMLStreamReader(wrapPrefixRemovingInputStream(inputStream));
}
final static private InputStream wrapPrefixRemovingInputStream(InputStream inputStream)
throws XMLStreamException, IOException {
PushbackInputStream pis = new PushbackInputStream(inputStream);
int b;
int count = 0;
while (count < 100 && (b = pis.read()) >= 0) {
if (++count > 100) {
throw new XMLStreamException(
"File starts with too much non-XML content to skip over");
} else if (b == '<') {
pis.unread(b);
break;
}
}
return pis;
}
}