/*
* Copyright 2013 Cloudera Inc.
*
* 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 org.kitesdk.morphline.saxon;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import javax.xml.stream.XMLStreamException;
import net.sf.saxon.s9api.Axis;
import net.sf.saxon.s9api.QName;
import net.sf.saxon.s9api.SaxonApiException;
import net.sf.saxon.s9api.XQueryCompiler;
import net.sf.saxon.s9api.XQueryEvaluator;
import net.sf.saxon.s9api.XQueryExecutable;
import net.sf.saxon.s9api.XdmItem;
import net.sf.saxon.s9api.XdmNode;
import net.sf.saxon.s9api.XdmNodeKind;
import net.sf.saxon.s9api.XdmSequenceIterator;
import net.sf.saxon.s9api.XdmValue;
import net.sf.saxon.trace.XQueryTraceListener;
import net.sf.saxon.value.UntypedAtomicValue;
import org.kitesdk.morphline.api.Command;
import org.kitesdk.morphline.api.CommandBuilder;
import org.kitesdk.morphline.api.MorphlineCompilationException;
import org.kitesdk.morphline.api.MorphlineContext;
import org.kitesdk.morphline.api.Record;
import org.kitesdk.morphline.base.Configs;
import com.typesafe.config.Config;
import com.typesafe.config.ConfigFactory;
/**
* Command that parses an InputStream that contains an XML document and runs the given XQuery over
* the XML document. For each item in the query result sequence, the command emits a morphline record
* containing the item's name-value pairs.
*/
public final class XQueryBuilder implements CommandBuilder {
@Override
public Collection<String> getNames() {
return Collections.singletonList("xquery");
}
@Override
public Command build(Config config, Command parent, Command child, MorphlineContext context) {
try {
return new XQuery(this, config, parent, child, context);
} catch (SaxonApiException e) {
throw new MorphlineCompilationException("Cannot compile", config, e);
} catch (IOException e) {
throw new MorphlineCompilationException("Cannot compile", config, e);
} catch (XMLStreamException e) {
throw new MorphlineCompilationException("Cannot compile", config, e);
}
}
///////////////////////////////////////////////////////////////////////////////
// Nested classes:
///////////////////////////////////////////////////////////////////////////////
private static final class XQuery extends SaxonCommand {
/*
* TODO: Add option to support streaming via fragmentPath.
*
* TODO: Add option to support serializing each item in the result sequence according to the XML
* Output Method of the <a target="_blank" href="http://www.w3.org/TR/xslt-xquery-serialization-30/">
* W3C XQuery/XSLT2 Serialization Spec</a>, with sequence normalization as defined therein.
*/
private final List<Fragment> fragments = new ArrayList();
public XQuery(CommandBuilder builder, Config config, Command parent, Command child, MorphlineContext context) throws SaxonApiException, IOException, XMLStreamException {
super(builder, config, parent, child, context);
List<? extends Config> fragmentConfigs = getConfigs().getConfigList(config, "fragments");
if (fragmentConfigs.size() == 0) {
throw new MorphlineCompilationException("At least one fragment must be defined", config);
}
if (fragmentConfigs.size() > 1) {
throw new MorphlineCompilationException("More than one fragment is not yet supported", config);
}
for (Config fragment : fragmentConfigs) {
String fragmentPath = getConfigs().getString(fragment, "fragmentPath");
if (!fragmentPath.equals("/")) {
throw new MorphlineCompilationException("Non-root fragment paths are not yet supported", config);
}
XQueryCompiler compiler = processor.newXQueryCompiler();
compiler.setErrorListener(new DefaultErrorListener());
compiler.setCompileWithTracing(isTracing);
compiler.setLanguageVersion(getConfigs().getString(config, "languageVersion", "1.0"));
XQueryExecutable executable = null;
String query = getConfigs().getString(fragment, "queryString", null);
if (query != null) {
executable = compiler.compile(query);
}
String queryFile = getConfigs().getString(fragment, "queryFile", null);
if (queryFile != null) {
executable = compiler.compile(new File(queryFile));
}
if (query == null && queryFile == null) {
throw new MorphlineCompilationException("Either query or queryFile must be defined", config);
}
if (query != null && queryFile != null) {
throw new MorphlineCompilationException("Must not define both query and queryFile at the same time", config);
}
XQueryEvaluator evaluator = executable.load();
Config variables = getConfigs().getConfig(fragment, "externalVariables", ConfigFactory.empty());
for (Map.Entry<String, Object> entry : new Configs().getEntrySet(variables)) {
XdmValue xdmValue = XdmNode.wrap(new UntypedAtomicValue(entry.getValue().toString()));
evaluator.setExternalVariable(new QName(entry.getKey()), xdmValue);
}
Config fileVariables = getConfigs().getConfig(fragment, "externalFileVariables", ConfigFactory.empty());
for (Map.Entry<String, Object> entry : new Configs().getEntrySet(fileVariables)) {
File file = new File(entry.getValue().toString());
XdmValue doc = parseXmlDocument(file);
evaluator.setExternalVariable(new QName(entry.getKey()), doc);
}
if (isTracing) {
evaluator.setTraceListener(new XQueryTraceListener()); // TODO redirect from stderr to SLF4J
}
fragments.add(new Fragment(fragmentPath, evaluator));
}
validateArguments();
}
@Override
protected boolean doProcess2(Record inputRecord, InputStream stream) throws SaxonApiException, XMLStreamException {
incrementNumRecords();
for (Fragment fragment : fragments) {
Record template = inputRecord.copy();
removeAttachments(template);
XdmNode document = parseXmlDocument(stream);
LOG.trace("XQuery input document: {}", document);
XQueryEvaluator evaluator = fragment.xQueryEvaluator;
evaluator.setContextItem(document);
int i = 0;
for (XdmItem item : evaluator) {
i++;
if (LOG.isTraceEnabled()) {
LOG.trace("XQuery result sequence item #{} is of class: {} with value: {}", new Object[] { i,
item.getUnderlyingValue().getClass().getName(), item });
}
if (item.isAtomicValue()) {
LOG.debug("Ignoring atomic value in result sequence: {}", item);
continue;
}
XdmNode node = (XdmNode) item;
Record outputRecord = template.copy();
boolean isNonEmpty = addRecordValues(node, Axis.SELF, XdmNodeKind.ATTRIBUTE, outputRecord);
isNonEmpty = addRecordValues(node, Axis.ATTRIBUTE, XdmNodeKind.ATTRIBUTE, outputRecord) || isNonEmpty;
isNonEmpty = addRecordValues(node, Axis.CHILD, XdmNodeKind.ELEMENT, outputRecord) || isNonEmpty;
if (isNonEmpty) { // pass record to next command in chain
if (!getChild().process(outputRecord)) {
return false;
}
}
}
}
return true;
}
// extract fields from query result sequence
private boolean addRecordValues(XdmNode node, Axis axis, XdmNodeKind nodeTest, Record record) {
boolean isEmpty = true;
XdmSequenceIterator iter = node.axisIterator(axis);
while (iter.hasNext()) {
XdmNode child = (XdmNode) iter.next();
if (child.getNodeKind() == nodeTest) {
String strValue = child.getStringValue();
if (strValue.length() > 0) {
record.put(child.getNodeName().getLocalName(), strValue);
isEmpty = false;
}
}
}
return !isEmpty;
}
///////////////////////////////////////////////////////////////////////////////
// Nested classes:
///////////////////////////////////////////////////////////////////////////////
private static final class Fragment {
private final String fragmentPath;
private final XQueryEvaluator xQueryEvaluator;
public Fragment(String fragmentPath, XQueryEvaluator xQueryEvaluator) {
this.fragmentPath = fragmentPath;
this.xQueryEvaluator = xQueryEvaluator;
}
}
}
}