org.apacheextras.camel.component.vtdxml.VtdXmlXPathBuilder Maven / Gradle / Ivy
/**************************************************************************************
http://code.google.com/a/apache-extras.org/p/camel-extra
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
02110-1301, USA.
http://www.gnu.org/licenses/gpl-2.0-standalone.html
***************************************************************************************/
package org.apacheextras.camel.component.vtdxml;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.InputStream;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import com.ximpleware.AutoPilot;
import com.ximpleware.ModifyException;
import com.ximpleware.NavException;
import com.ximpleware.VTDGen;
import com.ximpleware.VTDNav;
import com.ximpleware.XPathEvalException;
import com.ximpleware.XPathParseException;
import org.apache.camel.Exchange;
import org.apache.camel.Expression;
import org.apache.camel.Predicate;
import org.apache.camel.RuntimeExchangeException;
import org.apache.camel.RuntimeExpressionException;
import org.apache.camel.Service;
import org.apache.camel.spi.NamespaceAware;
import org.apache.camel.util.IOHelper;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
*
*/
public class VtdXmlXPathBuilder implements Expression, Predicate, NamespaceAware, Service {
private static final transient Logger LOG = LoggerFactory.getLogger(VtdXmlXPathBuilder.class);
private final String text;
private Map namespaces;
public VtdXmlXPathBuilder(String text) {
this.text = text;
}
public static VtdXmlXPathBuilder xpath(String text) {
return new VtdXmlXPathBuilder(text);
}
@Override
public String toString() {
return "VTDXPath: " + text;
}
@Override
public void setNamespaces(Map namespaces) {
this.namespaces = namespaces;
}
/**
* Registers the namespace prefix and URI with the builder so that the
* prefix can be used in XPath expressions
*
* @param prefix is the namespace prefix that can be used in the XPath
* expressions
* @param uri is the namespace URI to which the prefix refers
* @return the current builder
*/
public VtdXmlXPathBuilder namespace(String prefix, String uri) {
if (namespaces == null) {
namespaces = new HashMap();
}
namespaces.put(prefix, uri);
return this;
}
@Override
public boolean matches(Exchange exchange) {
try {
Object body = exchange.getIn().getMandatoryBody();
if (body instanceof File) {
// optimize for file
File file = (File) body;
return matchesFile(exchange, file);
} else {
// should be a byte[] array
byte[] bytes = exchange.getIn().getBody(byte[].class);
if (bytes == null) {
// go from input stream to byte array
InputStream is = exchange.getIn().getMandatoryBody(InputStream.class);
ByteArrayOutputStream bos = new ByteArrayOutputStream();
IOHelper.copyAndCloseInput(is, bos);
bytes = bos.toByteArray();
IOHelper.close(bos);
}
return matchesBody(exchange, bytes);
}
} catch (Exception e) {
throw new RuntimeExchangeException("Cannot process xpath " + text, exchange, e);
}
}
private boolean matchesFile(Exchange exchange, File file) throws Exception {
VTDGen vg = new VTDGen();
vg.parseFile(file.getAbsolutePath(), true);
VTDNav vn = vg.getNav();
AutoPilot ap = new AutoPilot(vn);
configureXPath(ap);
return ap.evalXPathToBoolean();
}
private boolean matchesBody(Exchange exchange, byte[] body) throws Exception {
VTDGen vg = new VTDGen();
vg.setDoc(body);
vg.parse(true);
VTDNav vn = vg.getNav();
AutoPilot ap = new AutoPilot(vn);
configureXPath(ap);
return ap.evalXPathToBoolean();
}
@Override
public T evaluate(Exchange exchange, Class type) {
Object result;
try {
// optimize for file
Object body = exchange.getIn().getMandatoryBody();
if (body instanceof File) {
// optimize for file
File file = (File) body;
result = evaluateFile(exchange, file);
} else {
// should be a byte[] array
byte[] bytes = exchange.getIn().getBody(byte[].class);
if (bytes == null) {
// go from input stream to byte array
InputStream is = exchange.getIn().getMandatoryBody(InputStream.class);
ByteArrayOutputStream bos = new ByteArrayOutputStream();
IOHelper.copyAndCloseInput(is, bos);
try {
bytes = bos.toByteArray();
} finally {
IOHelper.close(bos, "vtdxml", LOG);
}
}
result = evaluateBody(exchange, bytes);
}
} catch (Exception e) {
throw new RuntimeExpressionException("Cannot evaluate xpath " + text, e);
}
return exchange.getContext().getTypeConverter().convertTo(type, result);
}
private Object evaluateFile(Exchange exchange, File file) throws Exception {
VTDGen vg = new VTDGen();
vg.parseFile(file.getAbsolutePath(), true);
VTDNav vn = vg.getNav();
AutoPilot ap = new AutoPilot(vn);
configureXPath(ap);
return new VtdXmlIterator(vn, ap);
}
private Object evaluateBody(Exchange exchange, byte[] body) throws Exception {
VTDGen vg = new VTDGen();
vg.setDoc(body);
vg.parse(true);
VTDNav vn = vg.getNav();
AutoPilot ap = new AutoPilot(vn);
configureXPath(ap);
return new VtdXmlIterator(vn, ap);
}
protected void configureXPath(AutoPilot ap) throws XPathParseException {
// set namespaces
if (namespaces != null) {
for (Map.Entry entry : namespaces.entrySet()) {
if (LOG.isTraceEnabled()) {
LOG.trace("Using namespace {} -> {}", entry.getKey(), entry.getValue());
}
ap.declareXPathNameSpace(entry.getKey(), entry.getValue());
}
}
LOG.trace("SelectXPath {}", text);
ap.selectXPath(text);
}
/**
* Iterator to be used for XPath expressions
*/
private final class VtdXmlIterator implements Iterator {
private final VTDNav vn;
private final AutoPilot ap;
private int index = -1;
private volatile boolean nextCalled = true;
private VtdXmlIterator(VTDNav vn, AutoPilot ap) throws ModifyException {
this.vn = vn;
this.ap = ap;
}
@Override
public boolean hasNext() {
if (nextCalled) {
try {
index = ap.evalXPath();
} catch (XPathEvalException e) {
throw new RuntimeExpressionException("Cannot evaluate xpath " + text, e);
} catch (NavException e) {
throw new RuntimeExpressionException("Cannot navigate xpath " + text, e);
}
}
LOG.trace("hasNext index {}", index);
nextCalled = false;
return index != -1;
}
@Override
public Object next() {
nextCalled = true;
try {
// the code below can grab the namespace, to be included, but its much slower
// ElementFragmentNs ns = vn.getElementFragmentNs();
// return ns.toBytes();
// grab the next element, based on offset positioning
long l = vn.getElementFragment();
if (l != -1) {
int offset = (int) l;
int len = (int) (l >> 32);
return vn.toRawString(offset, len);
} else {
return null;
}
} catch (Exception e) {
throw new RuntimeException("Cannot extract String from index: " + index, e);
}
}
@Override
public void remove() {
// noop
}
}
@Override
public void start() throws Exception {
// noop
}
@Override
public void stop() throws Exception {
// noop
}
}
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