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Camel Saxon (XQuery/XPath) support
/**
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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.apache.camel.component.xquery;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.Reader;
import java.io.StringWriter;
import java.net.URL;
import java.util.Collection;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Properties;
import java.util.Set;
import java.util.concurrent.atomic.AtomicBoolean;
import javax.xml.transform.Result;
import javax.xml.transform.Source;
import javax.xml.transform.dom.DOMResult;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.sax.SAXSource;
import javax.xml.transform.stax.StAXSource;
import javax.xml.transform.stream.StreamResult;
import javax.xml.transform.stream.StreamSource;
import org.w3c.dom.Node;
import net.sf.saxon.Configuration;
import net.sf.saxon.lib.ModuleURIResolver;
import net.sf.saxon.om.DocumentInfo;
import net.sf.saxon.om.Item;
import net.sf.saxon.om.SequenceIterator;
import net.sf.saxon.om.StructuredQName;
import net.sf.saxon.query.DynamicQueryContext;
import net.sf.saxon.query.StaticQueryContext;
import net.sf.saxon.query.XQueryExpression;
import net.sf.saxon.trans.XPathException;
import net.sf.saxon.value.ObjectValue;
import net.sf.saxon.value.Whitespace;
import org.apache.camel.BytesSource;
import org.apache.camel.Exchange;
import org.apache.camel.Expression;
import org.apache.camel.Message;
import org.apache.camel.NoTypeConversionAvailableException;
import org.apache.camel.Predicate;
import org.apache.camel.Processor;
import org.apache.camel.RuntimeExpressionException;
import org.apache.camel.StringSource;
import org.apache.camel.component.bean.BeanInvocation;
import org.apache.camel.converter.IOConverter;
import org.apache.camel.spi.NamespaceAware;
import org.apache.camel.util.IOHelper;
import org.apache.camel.util.MessageHelper;
import org.apache.camel.util.ObjectHelper;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* Creates an XQuery builder.
*
* The XQueryExpression, as you would expect, can be executed repeatedly, as often as you want, in the same or in different threads.
*
* @version
*/
public abstract class XQueryBuilder implements Expression, Predicate, NamespaceAware, Processor {
private static final Logger LOG = LoggerFactory.getLogger(XQueryBuilder.class);
private Configuration configuration;
private XQueryExpression expression;
private StaticQueryContext staticQueryContext;
private Map parameters = new HashMap();
private Map namespacePrefixes = new HashMap();
private ResultFormat resultsFormat = ResultFormat.DOM;
private Properties properties = new Properties();
private Class resultType;
private final AtomicBoolean initialized = new AtomicBoolean(false);
private boolean stripsAllWhiteSpace = true;
private ModuleURIResolver moduleURIResolver;
private boolean allowStAX;
private String headerName;
@Override
public String toString() {
return "XQuery[" + expression + "]";
}
public void process(Exchange exchange) throws Exception {
Object body = evaluate(exchange);
exchange.getOut().setBody(body);
// propagate headers
exchange.getOut().getHeaders().putAll(exchange.getIn().getHeaders());
}
public T evaluate(Exchange exchange, Class type) {
Object result = evaluate(exchange);
return exchange.getContext().getTypeConverter().convertTo(type, result);
}
public Object evaluate(Exchange exchange) {
try {
LOG.debug("Evaluation: {} for exchange: {}", expression, exchange);
if (resultType != null) {
if (resultType.equals(String.class)) {
return evaluateAsString(exchange);
} else if (resultType.isAssignableFrom(Collection.class)) {
return evaluateAsList(exchange);
} else if (resultType.isAssignableFrom(Node.class)) {
return evaluateAsDOM(exchange);
} else {
throw new IllegalArgumentException("ResultType: " + resultType.getCanonicalName() + " not supported");
}
}
switch (resultsFormat) {
case Bytes:
return evaluateAsBytes(exchange);
case BytesSource:
return evaluateAsBytesSource(exchange);
case DOM:
return evaluateAsDOM(exchange);
case List:
return evaluateAsList(exchange);
case StringSource:
return evaluateAsStringSource(exchange);
case String:
default:
return evaluateAsString(exchange);
}
} catch (Exception e) {
throw new RuntimeExpressionException(e);
}
}
public List evaluateAsList(Exchange exchange) throws Exception {
LOG.debug("evaluateAsList: {} for exchange: {}", expression, exchange);
initialize(exchange);
return getExpression().evaluate(createDynamicContext(exchange));
}
public Object evaluateAsStringSource(Exchange exchange) throws Exception {
LOG.debug("evaluateAsString: {} for exchange: {}", expression, exchange);
initialize(exchange);
String text = evaluateAsString(exchange);
return new StringSource(text);
}
public Object evaluateAsBytesSource(Exchange exchange) throws Exception {
LOG.debug("evaluateAsBytesSource: {} for exchange: {}", expression, exchange);
initialize(exchange);
byte[] bytes = evaluateAsBytes(exchange);
return new BytesSource(bytes);
}
public Node evaluateAsDOM(Exchange exchange) throws Exception {
LOG.debug("evaluateAsDOM: {} for exchange: {}", expression, exchange);
initialize(exchange);
DOMResult result = new DOMResult();
DynamicQueryContext context = createDynamicContext(exchange);
XQueryExpression expression = getExpression();
expression.pull(context, result, properties);
return result.getNode();
}
public byte[] evaluateAsBytes(Exchange exchange) throws Exception {
LOG.debug("evaluateAsBytes: {} for exchange: {}", expression, exchange);
initialize(exchange);
ByteArrayOutputStream buffer = new ByteArrayOutputStream();
Result result = new StreamResult(buffer);
getExpression().pull(createDynamicContext(exchange), result, properties);
byte[] answer = buffer.toByteArray();
buffer.close();
return answer;
}
public String evaluateAsString(Exchange exchange) throws Exception {
LOG.debug("evaluateAsString: {} for exchange: {}", expression, exchange);
initialize(exchange);
StringWriter buffer = new StringWriter();
SequenceIterator iter = getExpression().iterator(createDynamicContext(exchange));
for (Item item = iter.next(); item != null; item = iter.next()) {
buffer.append(item.getStringValueCS());
}
String answer = buffer.toString();
buffer.close();
return answer;
}
public boolean matches(Exchange exchange) {
LOG.debug("Matches: {} for exchange: {}", expression, exchange);
try {
List list = evaluateAsList(exchange);
return matches(exchange, list);
} catch (Exception e) {
throw new RuntimeExpressionException(e);
}
}
@Deprecated
public void assertMatches(String text, Exchange exchange) throws AssertionError {
List list;
try {
list = evaluateAsList(exchange);
} catch (Exception e) {
throw new AssertionError(e);
}
if (!matches(exchange, list)) {
throw new AssertionError(this + " failed on " + exchange + " as evaluated: " + list);
}
}
// Static helper methods
//-------------------------------------------------------------------------
public static XQueryBuilder xquery(final String queryText) {
return new XQueryBuilder() {
protected XQueryExpression createQueryExpression(StaticQueryContext staticQueryContext)
throws XPathException {
return staticQueryContext.compileQuery(queryText);
}
};
}
public static XQueryBuilder xquery(final Reader reader) {
return new XQueryBuilder() {
protected XQueryExpression createQueryExpression(StaticQueryContext staticQueryContext)
throws XPathException, IOException {
return staticQueryContext.compileQuery(reader);
}
};
}
public static XQueryBuilder xquery(final InputStream in, final String characterSet) {
return new XQueryBuilder() {
protected XQueryExpression createQueryExpression(StaticQueryContext staticQueryContext)
throws XPathException, IOException {
return staticQueryContext.compileQuery(in, characterSet);
}
};
}
public static XQueryBuilder xquery(File file, String characterSet) throws IOException {
return xquery(IOConverter.toInputStream(file), characterSet);
}
public static XQueryBuilder xquery(URL url, String characterSet) throws IOException {
return xquery(IOConverter.toInputStream(url), characterSet);
}
public static XQueryBuilder xquery(File file) throws IOException {
return xquery(IOConverter.toInputStream(file), ObjectHelper.getDefaultCharacterSet());
}
public static XQueryBuilder xquery(URL url) throws IOException {
return xquery(IOConverter.toInputStream(url), ObjectHelper.getDefaultCharacterSet());
}
// Fluent API
// -------------------------------------------------------------------------
public XQueryBuilder parameter(String name, Object value) {
parameters.put(name, value);
return this;
}
public XQueryBuilder namespace(String prefix, String uri) {
namespacePrefixes.put(prefix, uri);
// more namespace, we must re initialize
initialized.set(false);
return this;
}
public XQueryBuilder resultType(Class resultType) {
setResultType(resultType);
return this;
}
public XQueryBuilder asBytes() {
setResultsFormat(ResultFormat.Bytes);
return this;
}
public XQueryBuilder asBytesSource() {
setResultsFormat(ResultFormat.BytesSource);
return this;
}
public XQueryBuilder asDOM() {
setResultsFormat(ResultFormat.DOM);
return this;
}
public XQueryBuilder asDOMSource() {
setResultsFormat(ResultFormat.DOMSource);
return this;
}
public XQueryBuilder asList() {
setResultsFormat(ResultFormat.List);
return this;
}
public XQueryBuilder asString() {
setResultsFormat(ResultFormat.String);
return this;
}
public XQueryBuilder asStringSource() {
setResultsFormat(ResultFormat.StringSource);
return this;
}
public XQueryBuilder stripsAllWhiteSpace() {
setStripsAllWhiteSpace(true);
return this;
}
public XQueryBuilder stripsIgnorableWhiteSpace() {
setStripsAllWhiteSpace(false);
return this;
}
/**
* Enables to allow using StAX.
*
* When enabled StAX is preferred as the first choice as {@link Source}.
*/
public XQueryBuilder allowStAX() {
setAllowStAX(true);
return this;
}
// Properties
// -------------------------------------------------------------------------
/**
* Configures the namespace context from the given DOM element
*/
public void setNamespaces(Map namespaces) {
namespacePrefixes.putAll(namespaces);
// more namespace, we must re initialize
initialized.set(false);
}
public XQueryExpression getExpression() throws IOException, XPathException {
return expression;
}
public Configuration getConfiguration() {
return configuration;
}
public void setConfiguration(Configuration configuration) {
this.configuration = configuration;
// change configuration, we must re initialize
initialized.set(false);
}
public StaticQueryContext getStaticQueryContext() {
return staticQueryContext;
}
public void setStaticQueryContext(StaticQueryContext staticQueryContext) {
this.staticQueryContext = staticQueryContext;
// change context, we must re initialize
initialized.set(false);
}
public Map getParameters() {
return parameters;
}
public void setParameters(Map parameters) {
this.parameters = parameters;
}
public Properties getProperties() {
return properties;
}
public void setProperties(Properties properties) {
this.properties = properties;
}
public ResultFormat getResultsFormat() {
return resultsFormat;
}
public void setResultsFormat(ResultFormat resultsFormat) {
this.resultsFormat = resultsFormat;
}
public Class getResultType() {
return resultType;
}
public void setResultType(Class resultType) {
this.resultType = resultType;
}
public ModuleURIResolver getModuleURIResolver() {
return moduleURIResolver;
}
public void setModuleURIResolver(ModuleURIResolver moduleURIResolver) {
this.moduleURIResolver = moduleURIResolver;
}
public boolean isStripsAllWhiteSpace() {
return stripsAllWhiteSpace;
}
public void setStripsAllWhiteSpace(boolean stripsAllWhiteSpace) {
this.stripsAllWhiteSpace = stripsAllWhiteSpace;
}
public String getHeaderName() {
return headerName;
}
public void setHeaderName(String headerName) {
this.headerName = headerName;
}
public boolean isAllowStAX() {
return allowStAX;
}
public void setAllowStAX(boolean allowStAX) {
this.allowStAX = allowStAX;
}
// Implementation methods
// -------------------------------------------------------------------------
/**
* A factory method to create the XQuery expression
*/
protected abstract XQueryExpression createQueryExpression(StaticQueryContext staticQueryContext)
throws XPathException, IOException;
/**
* Creates a dynamic context for the given exchange
*/
protected DynamicQueryContext createDynamicContext(Exchange exchange) throws Exception {
Configuration config = getConfiguration();
DynamicQueryContext dynamicQueryContext = new DynamicQueryContext(config);
Message in = exchange.getIn();
Item item = null;
if (ObjectHelper.isNotEmpty(getHeaderName())) {
item = in.getHeader(getHeaderName(), Item.class);
} else {
item = in.getBody(Item.class);
}
if (item != null) {
dynamicQueryContext.setContextItem(item);
} else {
Object body = null;
if (ObjectHelper.isNotEmpty(getHeaderName())) {
body = in.getHeader(getHeaderName());
} else {
body = in.getBody();
}
// the underlying input stream, which we need to close to avoid locking files or other resources
InputStream is = null;
try {
Source source;
// only convert to input stream if really needed
if (isInputStreamNeeded(exchange)) {
if (ObjectHelper.isNotEmpty(getHeaderName())) {
is = exchange.getIn().getHeader(getHeaderName(), InputStream.class);
} else {
is = exchange.getIn().getBody(InputStream.class);
}
source = getSource(exchange, is);
} else {
source = getSource(exchange, body);
}
// special for bean invocation
if (source == null) {
if (body instanceof BeanInvocation) {
// if its a null bean invocation then handle that
BeanInvocation bi = exchange.getContext().getTypeConverter().convertTo(BeanInvocation.class, body);
if (bi.getArgs() != null && bi.getArgs().length == 1 && bi.getArgs()[0] == null) {
// its a null argument from the bean invocation so use null as answer
source = null;
}
}
}
if (source == null) {
// indicate it was not possible to convert to a Source type
throw new NoTypeConversionAvailableException(body, Source.class);
}
DocumentInfo doc = config.buildDocument(source);
dynamicQueryContext.setContextItem(doc);
} finally {
// can deal if is is null
IOHelper.close(is);
}
}
configureQuery(dynamicQueryContext, exchange);
// call the reset if the in message body is StreamCache
MessageHelper.resetStreamCache(exchange.getIn());
return dynamicQueryContext;
}
/**
* Checks whether we need an {@link InputStream} to access the message body.
*
* Depending on the content in the message body, we may not need to convert
* to {@link InputStream}.
*
* @param exchange the current exchange
* @return true to convert to {@link InputStream} beforehand converting to {@link Source} afterwards.
*/
protected boolean isInputStreamNeeded(Exchange exchange) {
Object body = exchange.getIn().getBody();
if (body == null) {
return false;
}
if (body instanceof Source) {
return false;
} else if (body instanceof String) {
return false;
} else if (body instanceof byte[]) {
return false;
} else if (body instanceof Node) {
return false;
}
// yes an input stream is needed
return true;
}
/**
* Converts the inbound body to a {@link Source}, if the body is not already a {@link Source}.
*
* This implementation will prefer to source in the following order:
*
* - StAX - Is StAX is allowed
* - SAX - SAX as 2nd choice
* - Stream - Stream as 3rd choice
* - DOM - DOM as 4th choice
*
*/
protected Source getSource(Exchange exchange, Object body) {
// body may already be a source
if (body instanceof Source) {
return (Source) body;
}
Source source = null;
if (isAllowStAX()) {
source = exchange.getContext().getTypeConverter().tryConvertTo(StAXSource.class, exchange, body);
}
if (source == null) {
// then try SAX
source = exchange.getContext().getTypeConverter().tryConvertTo(SAXSource.class, exchange, body);
}
if (source == null) {
// then try stream
source = exchange.getContext().getTypeConverter().tryConvertTo(StreamSource.class, exchange, body);
}
if (source == null) {
// and fallback to DOM
source = exchange.getContext().getTypeConverter().tryConvertTo(DOMSource.class, exchange, body);
}
return source;
}
/**
* Configures the dynamic context with exchange specific parameters
*/
protected void configureQuery(DynamicQueryContext dynamicQueryContext, Exchange exchange)
throws Exception {
addParameters(dynamicQueryContext, exchange.getProperties());
addParameters(dynamicQueryContext, exchange.getIn().getHeaders(), "in.headers.");
dynamicQueryContext.setParameter(
StructuredQName.fromClarkName("in.body"),
new ObjectValue(exchange.getIn().getBody())
);
addParameters(dynamicQueryContext, getParameters());
dynamicQueryContext.setParameter(
StructuredQName.fromClarkName("exchange"),
new ObjectValue(exchange)
);
if (exchange.hasOut() && exchange.getPattern().isOutCapable()) {
dynamicQueryContext.setParameter(
StructuredQName.fromClarkName("out.body"),
new ObjectValue(exchange.getOut().getBody())
);
addParameters(dynamicQueryContext, exchange.getOut().getHeaders(), "out.headers.");
}
}
protected void addParameters(DynamicQueryContext dynamicQueryContext, Map map) {
addParameters(dynamicQueryContext, map, "");
}
protected void addParameters(DynamicQueryContext dynamicQueryContext, Map map, String parameterPrefix) {
Set> propertyEntries = map.entrySet();
for (Map.Entry entry : propertyEntries) {
dynamicQueryContext.setParameter(
StructuredQName.fromClarkName(parameterPrefix + entry.getKey()),
new ObjectValue(entry.getValue())
);
}
}
protected boolean matches(Exchange exchange, List results) {
return ObjectHelper.matches(results);
}
/**
* Initializes this builder - Must be invoked before evaluation.
*/
protected synchronized void initialize(Exchange exchange) throws XPathException, IOException {
// must use synchronized for concurrency issues and only let it initialize once
if (!initialized.get()) {
LOG.debug("Initializing XQueryBuilder {}", this);
if (configuration == null) {
configuration = new Configuration();
//configuration.setHostLanguage(Configuration.XQUERY);
configuration.setStripsWhiteSpace(isStripsAllWhiteSpace() ? Whitespace.ALL : Whitespace.IGNORABLE);
LOG.debug("Created new Configuration {}", configuration);
} else {
LOG.debug("Using existing Configuration {}", configuration);
}
staticQueryContext = getConfiguration().newStaticQueryContext();
if (moduleURIResolver != null) {
staticQueryContext.setModuleURIResolver(moduleURIResolver);
}
Set> entries = namespacePrefixes.entrySet();
for (Map.Entry entry : entries) {
String prefix = entry.getKey();
String uri = entry.getValue();
staticQueryContext.declareNamespace(prefix, uri);
staticQueryContext.setInheritNamespaces(true);
}
expression = createQueryExpression(staticQueryContext);
initialized.set(true);
}
// let the configuration be accessible on the exchange as its shared for this evaluation
// and can be needed by 3rd party type converters or other situations (camel-artixds)
exchange.setProperty("CamelSaxonConfiguration", configuration);
}
}
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