vgritsenko 02/01/09 21:40:35
Added: src/scratchpad/src/org/apache/cocoon/transformation
XMLDBTransformer.java
Log:
XMLDB transformer allows to:
- create
- delete
- update (using XUpdate)
resources in XML:DB database
Revision Changes Path
1.1
xml-cocoon2/src/scratchpad/src/org/apache/cocoon/transformation/XMLDBTransformer.java
Index: XMLDBTransformer.java
===================================================================
/*****************************************************************************
* Copyright (C) The Apache Software Foundation. All rights reserved. *
* ------------------------------------------------------------------------- *
* This software is published under the terms of the Apache Software License *
* version 1.1, a copy of which has been included with this distribution in *
* the LICENSE file. *
*****************************************************************************/
package org.apache.cocoon.transformation;
import org.apache.avalon.excalibur.pool.Poolable;
import org.apache.avalon.framework.activity.Disposable;
import org.apache.avalon.framework.activity.Initializable;
import org.apache.avalon.framework.parameters.Parameters;
import org.apache.avalon.framework.configuration.Configurable;
import org.apache.avalon.framework.configuration.Configuration;
import org.apache.avalon.framework.configuration.ConfigurationException;
import org.apache.cocoon.util.TraxErrorHandler;
import org.apache.cocoon.caching.CacheValidity;
import org.apache.cocoon.caching.Cacheable;
import org.apache.cocoon.environment.SourceResolver;
import org.apache.cocoon.ProcessingException;
import org.apache.cocoon.ResourceNotFoundException;
import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.AttributesImpl;
import org.xmldb.api.base.Database;
import org.xmldb.api.base.Resource;
import org.xmldb.api.base.Collection;
import org.xmldb.api.base.XMLDBException;
import org.xmldb.api.DatabaseManager;
import org.xmldb.api.modules.XUpdateQueryService;
import javax.xml.transform.sax.TransformerHandler;
import javax.xml.transform.sax.SAXTransformerFactory;
import javax.xml.transform.stream.StreamResult;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.OutputKeys;
import javax.xml.transform.TransformerConfigurationException;
import java.io.IOException;
import java.io.StringWriter;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Properties;
/**
* This transformer allows to perform resource creation, deletion, and
* XUpdate command execution in XML:DB.
*
* <p>Definition:</p>
* <pre>
* <map:transformer name="xmldb" src="www.XMLDBTransformer">
* <driver>org.apache.xindice.client.xmldb.DatabaseImpl</driver>
* <base>xmldb:xindice:///db/collection</base>
* </map:transformer>
* </pre>
*
* <p>Invokation:</p>
* <pre>
* <map:transform type="xmldb">
* <map:parameter name="base" value="xmldb:xindice:///db/collection"/>
* </map:transform>
* </pre>
*
* <p>Input XML document example:</p>
* <pre>
* <page xmlns:xindice="http://apache.org/cocoon/xmldb/1.0">
* ...
* <xindice:query type="create" oid="xmldb-object-id">
* <page>
* XML Object body
* </page>
* </xindice:query>
*
* <xindice:query type="delete" oid="xmldb-object-id"/>
*
* <xindice:query type="update" oid="xmldb-object-id">
* <xu:modifications version="1.0" xmlns:xu="http://www.xmldb.org/xupdate">
* <xu:remove select="/person/phone[@type = 'home']"/>
* <xu:update select="/person/phone[@type = 'work']">
* 480-300-3003
* </xu:update>
* </xu:modifications>
* </xindice:query>
* ...
* </page>
* </pre>
*
* <p>Output XML document example:</p>
* <pre>
* <page xmlns:xindice="http://apache.org/cocoon/xmldb/1.0">
* ...
* <xindice:query type="create" oid="xmldb-object-id" result="success"/>
*
* <xindice:query type="delete" oid="xmldb-object-id" result="success"/>
*
* <xindice:query type="update" oid="xmldb-object-id" result="failure">
* Resource xmldb-object-id is not found
* </xindice:query>
* ...
* </page>
* </pre>
*
* <p>Known bugs and limitations:</p>
* <ul>
* <li>XUpdate is not tested</li>
* <li>No namespaces with Xalan (see AbstractTextSerializer)</li>
* </ul>
*
* @author <a href="mailto:[EMAIL PROTECTED]";>Vadim Gritsenko</a>
* @version CVS $Revision: 1.1 $ $Date: 2002/01/10 05:40:35 $
*/
public class XMLDBTransformer extends AbstractTransformer
implements Disposable, Cacheable, Poolable, Configurable, Initializable {
private static String XMLDB_URI = "http://apache.org/cocoon/xmldb/1.0";;
private static String XMLDB_QUERY_ELEMENT = "query";
private static String XMLDB_QUERY_TYPE_ATTRIBUTE = "type";
private static String XMLDB_QUERY_OID_ATTRIBUTE = "oid";
private static String XMLDB_QUERY_RESULT_ATTRIBUTE = "result";
/** The trax <code>TransformerFactory</code> used by this transformer. */
private SAXTransformerFactory tfactory = null;
private Properties format = new Properties();
/** The map of namespace prefixes. */
private Map prefixMap = new HashMap();
/** XML:DB driver class name. */
private String driver = null;
/** Default collection name. */
private String default_base = null;
/** Current collection name. */
private String base = null;
/** Current collection. */
private Collection collection;
/** Operation. One of: create, delete, update. */
private String operation;
/** Document ID. Can be null if update is performed on collection. */
private String key;
private StringWriter queryWriter;
private TransformerHandler queryHandler;
/** True when inside <query> element. */
private boolean processing;
public void XMLDBTransformer() {
format.put(OutputKeys.ENCODING, "utf-8");
format.put(OutputKeys.INDENT, "no");
format.put(OutputKeys.OMIT_XML_DECLARATION, "yes");
}
public void configure(Configuration configuration) throws ConfigurationException
{
Configuration driver = configuration.getChild("driver");
if (driver == null || driver.getValue() == null)
throw new ConfigurationException("Required driver parameter is
missing.");
this.driver = driver.getValue();
Configuration default_base = configuration.getChild("base");
if (default_base != null)
this.default_base = default_base.getValue();
}
/**
* Initializes XML:DB database instance using specified driver class.
*/
public void initialize() throws Exception {
Class c = Class.forName(driver);
Database database = (Database)c.newInstance();
DatabaseManager.registerDatabase(database);
}
/** Setup the transformer. */
public void setup(SourceResolver resolver, Map objectModel, String src,
Parameters par)
throws ProcessingException, SAXException, IOException {
this.base = par.getParameter("base", this.default_base);
if (this.base == null)
throw new ProcessingException("Required base parameter is missing.
Syntax is: xmldb:xindice:///db/collection");
try {
this.collection = DatabaseManager.getCollection(base);
} catch (XMLDBException e) {
throw new ProcessingException("Could not get collection " + base + ": "
+ e.errorCode, e);
}
if(this.collection == null)
throw new ResourceNotFoundException("Collection " + base + " does not
exist");
}
/**
* Helper for TransformerFactory.
*/
protected SAXTransformerFactory getTransformerFactory()
{
if(tfactory == null) {
tfactory = (SAXTransformerFactory) TransformerFactory.newInstance();
tfactory.setErrorListener(new TraxErrorHandler(getLogger()));
}
return tfactory;
}
/**
* Generate the unique key.
* This key must be unique inside the space of this component.
*
* @return The generated key hashes the src
*/
public long generateKey() {
return 1;
}
/**
* Generate the validity object.
*
* @return The generated validity object or <code>null</code> if the
* component is currently not cacheable.
*/
public CacheValidity generateValidity() {
return null;
}
/**
* Receive notification of the beginning of a document.
*/
public void startDocument() throws SAXException {
super.startDocument();
}
/**
* Receive notification of the end of a document.
*/
public void endDocument() throws SAXException {
super.endDocument();
}
/**
* Begin the scope of a prefix-URI Namespace mapping.
*
* @param prefix The Namespace prefix being declared.
* @param uri The Namespace URI the prefix is mapped to.
*/
public void startPrefixMapping(String prefix, String uri) throws SAXException {
if (!processing) {
super.startPrefixMapping(prefix,uri);
prefixMap.put(prefix,uri);
} else if (this.queryHandler != null){
this.queryHandler.startPrefixMapping(prefix, uri);
}
}
/**
* End the scope of a prefix-URI mapping.
*
* @param prefix The prefix that was being mapping.
*/
public void endPrefixMapping(String prefix) throws SAXException {
if (!processing) {
super.endPrefixMapping(prefix);
prefixMap.remove(prefix);
} else if (this.queryHandler != null){
this.queryHandler.endPrefixMapping(prefix);
}
}
/**
* Receive notification of the beginning of an element.
*
* @param uri The Namespace URI, or the empty string if the element has no
* Namespace URI or if Namespace
* processing is not being performed.
* @param loc The local name (without prefix), or the empty string if
* Namespace processing is not being performed.
* @param raw The raw XML 1.0 name (with prefix), or the empty string if
* raw names are not available.
* @param a The attributes attached to the element. If there are no
* attributes, it shall be an empty Attributes object.
*/
public void startElement(String uri, String loc, String raw, Attributes a)
throws SAXException {
if (!processing) {
if (XMLDB_URI.equals(uri) && XMLDB_QUERY_ELEMENT.equals(loc)){
this.operation = a.getValue(XMLDB_QUERY_TYPE_ATTRIBUTE);
if(!"create".equals(operation) && !"delete".equals(operation) &&
!"update".equals(operation)) {
throw new SAXException("Supported operation types are: create,
delete");
}
this.key = a.getValue(XMLDB_QUERY_OID_ATTRIBUTE);
if(!"update".equals(operation) && this.key == null) {
throw new SAXException("Object ID is missing in xmldb element");
}
processing = true;
if (!"delete".equals(operation)) {
// Prepare SAX query writer
queryWriter = new StringWriter(256);
try {
this.queryHandler =
getTransformerFactory().newTransformerHandler();
this.queryHandler.setResult(new StreamResult(queryWriter));
this.queryHandler.getTransformer().setOutputProperties(format);
} catch (TransformerConfigurationException e) {
throw new SAXException("Failed to get transformer handler",
e);
}
// Start query document
this.queryHandler.startDocument();
Iterator itt = prefixMap.entrySet().iterator();
while ( itt.hasNext() ) {
Map.Entry entry = (Map.Entry)itt.next();
this.queryHandler.startPrefixMapping((String)entry.getKey(),
(String)entry.getValue());
}
}
} else {
super.startElement(uri,loc,raw,a);
}
} else if (this.queryHandler != null){
this.queryHandler.startElement(uri,loc,raw,a);
}
}
/**
* Receive notification of the end of an element.
*
* @param uri The Namespace URI, or the empty string if the element has no
* Namespace URI or if Namespace
* processing is not being performed.
* @param loc The local name (without prefix), or the empty string if
* Namespace processing is not being performed.
* @param raw The raw XML 1.0 name (with prefix), or the empty string if
* raw names are not available.
*/
public void endElement(String uri, String loc, String raw)
throws SAXException {
if (!processing) {
super.endElement(uri,loc,raw);
} else {
if (XMLDB_URI.equals(uri) && XMLDB_QUERY_ELEMENT.equals(loc)){
processing = false;
String document = null;
if (this.queryHandler != null){
// Finish building query. Remove existing prefix mappings.
Iterator itt = prefixMap.entrySet().iterator();
while ( itt.hasNext() ) {
Map.Entry entry = (Map.Entry) itt.next();
this.queryHandler.endPrefixMapping((String)entry.getKey());
}
this.queryHandler.endDocument();
document = this.queryWriter.toString();
}
// Perform operation
String result = "failure";
String message = null;
if("create".equals(operation)) {
try {
System.out.println("XI: Creating document: " + this.key);
Resource resource = collection.createResource(key,
"XMLResource");
resource.setContent(document);
collection.storeResource(resource);
result = "success";
} catch (XMLDBException e) {
message = "Failed to create resource " + key + ": " +
e.errorCode;
getLogger().debug(message, e);
}
} else if("delete".equals(operation)) {
try {
System.out.println("XI: Deleting document: " + this.key);
Resource resource = collection.getResource(this.key);
if (resource == null) {
message = "Resource " + this.key + " does not exist";
getLogger().debug(message);
} else {
collection.removeResource(resource);
}
result = "success";
} catch (XMLDBException e) {
message = "Failed to delete resource " + key + ": " +
e.errorCode;
getLogger().debug(message, e);
}
} else if("update".equals(operation)) {
try {
XUpdateQueryService service =
(XUpdateQueryService)
collection.getService("XUpdateQueryService", "1.0");
long count = (this.key == null)?
service.update(document) :
service.updateResource(this.key, document);
message = count + " entries updated.";
System.out.println("XI: " + message);
result = "success";
} catch (XMLDBException e) {
message = "Failed to update resource " + key + ": " +
e.errorCode;
getLogger().debug(message, e);
}
}
// Report result
AttributesImpl attrs = new AttributesImpl();
attrs.addAttribute(null, XMLDB_QUERY_OID_ATTRIBUTE,
XMLDB_QUERY_OID_ATTRIBUTE, "CDATA", this.key);
attrs.addAttribute(null, XMLDB_QUERY_TYPE_ATTRIBUTE,
XMLDB_QUERY_TYPE_ATTRIBUTE, "CDATA", this.operation);
if (message == null)
attrs.addAttribute(null, XMLDB_QUERY_RESULT_ATTRIBUTE,
XMLDB_QUERY_RESULT_ATTRIBUTE, "CDATA", "success");
else
attrs.addAttribute(null, XMLDB_QUERY_RESULT_ATTRIBUTE,
XMLDB_QUERY_RESULT_ATTRIBUTE, "CDATA", "failure");
super.startElement(uri, loc, raw, attrs);
if (message != null) {
super.characters(message.toCharArray(), 0, message.length());
}
super.endElement(uri, loc, raw);
} else if (this.queryHandler != null){
this.queryHandler.endElement(uri, loc, raw);
}
}
}
/**
* Receive notification of character data.
*
* @param c The characters from the XML document.
* @param start The start position in the array.
* @param len The number of characters to read from the array.
*/
public void characters(char c[], int start, int len) throws SAXException {
if (!processing) {
super.characters(c,start,len);
} else if (this.queryHandler != null){
this.queryHandler.characters(c,start,len);
}
}
/**
* Receive notification of ignorable whitespace in element content.
*
* @param c The characters from the XML document.
* @param start The start position in the array.
* @param len The number of characters to read from the array.
*/
public void ignorableWhitespace(char c[], int start, int len) throws
SAXException {
if (!processing) {
super.ignorableWhitespace(c,start,len);
} else if (this.queryHandler != null){
this.queryHandler.ignorableWhitespace(c,start,len);
}
}
/**
* Receive notification of a processing instruction.
*
* @param target The processing instruction target.
* @param data The processing instruction data, or null if none was
* supplied.
*/
public void processingInstruction(String target, String data) throws
SAXException {
if (!processing) {
super.processingInstruction(target,data);
} else if (this.queryHandler != null){
this.queryHandler.processingInstruction(target,data);
}
}
/**
* Receive notification of a skipped entity.
*
* @param name The name of the skipped entity. If it is a parameter
* entity, the name will begin with '%'.
*/
public void skippedEntity(String name) throws SAXException {
if (!processing) {
super.skippedEntity(name);
} else if (this.queryHandler != null){
this.queryHandler.skippedEntity(name);
}
}
/**
* Report the start of DTD declarations, if any.
*
* @param name The document type name.
* @param publicId The declared public identifier for the external DTD
* subset, or null if none was declared.
* @param systemId The declared system identifier for the external DTD
* subset, or null if none was declared.
*/
public void startDTD(String name, String publicId, String systemId) throws
SAXException {
if (!processing) {
super.startDTD(name,publicId,systemId);
} else {
throw new SAXException(
"Recieved startDTD after beginning SVG extraction process."
);
}
}
/**
* Report the end of DTD declarations.
*/
public void endDTD() throws SAXException {
if (!processing) {
super.endDTD();
} else {
throw new SAXException("Recieved endDTD after xmldb element.");
}
}
/**
* Report the beginning of an entity.
*
* @param name The name of the entity. If it is a parameter entity, the
* name will begin with '%'.
*/
public void startEntity(String name) throws SAXException {
if (!processing) {
super.startEntity(name);
} else if (this.queryHandler != null){
this.queryHandler.startEntity(name);
}
}
/**
* Report the end of an entity.
*
* @param name The name of the entity that is ending.
*/
public void endEntity(String name) throws SAXException {
if (!processing) {
super.endEntity(name);
} else if (this.queryHandler != null){
this.queryHandler.endEntity(name);
}
}
/**
* Report the start of a CDATA section.
*/
public void startCDATA() throws SAXException {
if (!processing) {
super.startCDATA();
} else if (this.queryHandler != null){
this.queryHandler.startCDATA();
}
}
/**
* Report the end of a CDATA section.
*/
public void endCDATA() throws SAXException {
if (!processing) {
super.endCDATA();
} else if (this.queryHandler != null){
this.queryHandler.endCDATA();
}
}
/**
* Report an XML comment anywhere in the document.
*
* @param ch An array holding the characters in the comment.
* @param start The starting position in the array.
* @param len The number of characters to use from the array.
*/
public void comment(char ch[], int start, int len) throws SAXException {
if (!processing) {
super.comment(ch,start,len);
} else if (this.queryHandler != null){
this.queryHandler.comment(ch,start,len);
}
}
public void recycle() {
this.prefixMap.clear();
this.queryHandler = null;
this.queryWriter = null;
try {
if (collection != null) collection.close();
} catch (XMLDBException e) {
getLogger().error("Failed to close collection " + base + ". Error " +
e.errorCode, e);
}
collection = null;
}
/**
* dispose
*/
public void dispose() {
}
}
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