Hello, Vadim,
Thank you for the message.
I think search over multiple collections of similar document is a needed
feature. By partitioning the database into smaller collections may improve the
performance. I have documents to store in a collection tree like:
/db/proposals
/VLA
/200402
/200406
/200410
/VLBA
/200402
/200406
/200410
/EVLA
/200402
/200406
/200410
/GBT
/200402
/200406
/200410
I modified XPathQuery.java to do multiple collection search.
The are 2 ways to specified a collection list. The first uses a comma or
semi-colon
separated list, for example:
xindice xpath -c
xmldb:xindice://localhost:8080/db/proposals/VLA/200402;xmldb:xindice://localhost:8080/db/proposals/VLBA/200406
The second uses * to indicate all the child collections, for example
xindice xpath -c xmldb:xindice://localhost:8080/db/proposals/*/200402
or
xindice xpath -c xmldb:xindice://localhost:8080/db/proposals/VLA/*
The combination of the 2 way also ok.
Attached XPathQuery.java contains my modification to the original file.
I added 2 private functions to extract collection list and modified execute
method to loop over all the collection list.
I am new to xindice and am not sure if this modification make sense or
if it has impact on other modules.
Honglin Ye
National Radio Astronomy Observatory
Socorro, NM USA
Honglin Ye wrote:
> Honglin Ye wrote:
>
>> Is it possible to query db over multiple collection?
>>
>> For exacmple
>>
>> xindice xpath -c xmldb:xindice://host:8080/db/root/ -q "/root/childre"
>>
> sorry, it should read
>
> xindice xpath -c xmldb:xindice://host:8080/db/root/* -q "/root/childre"
See Xindice website, Todo page:
<strong>The Query Engine</strong> The query engine has basic
functionality right now. Indexing and XPath query work against a
Collection, but no unified cross-Collection query system currently
exists.
In short:
No, Xindice currently does not support quering over multiple connections. You
are welcome to enhance Xindice and send in a patch.
Thanks,
Vadim
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* originally based on software copyright (c) 1999-2001, The dbXML
* Group, L.L.C., http://www.dbxmlgroup.com. For more
* information on the Apache Software Foundation, please see
* <http://www.apache.org/>.
*
* CVS $Id: XPathQuery.java,v 1.11 2003/08/12 02:57:30 vladimir Exp $
*/
package org.apache.xindice.tools.command;
import org.apache.xindice.tools.XMLTools;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.xmldb.api.DatabaseManager;
import org.xmldb.api.base.Collection;
import org.xmldb.api.base.ResourceIterator;
import org.xmldb.api.base.ResourceSet;
import org.xmldb.api.base.XMLDBException;
import org.xmldb.api.modules.XMLResource;
import org.xmldb.api.modules.XPathQueryService;
import java.util.Hashtable;
import java.util.StringTokenizer;
import java.util.ArrayList;
/**
* SingleDocumentQuery is designed to enable the user/admin to XPathQuery
* a Collection for a Single Document.
*
* @version CVS $Revision: 1.11 $, $Date: 2003/08/12 02:57:30 $
*/
public class XPathQuery extends Command {
private static final Log log = LogFactory.getLog(XPathQuery.class);
public boolean execute(Hashtable table) throws Exception {
Collection col = null;
try {
if ((String) table.get(XMLTools.COLLECTION) == null) {
System.out.println("ERROR : Collection name and switch required");
return false;
}
if ((String) table.get(XMLTools.QUERY) == "") {
System.out.println("ERROR : Query and switch required");
return false;
}
String querystring = (String) table.get(XMLTools.QUERY);
XPathQueryService service = null;
ResourceIterator results = null;
ArrayList colList = new ArrayList(3);
getCollectionList(table, colList);
System.out.println("colList size=" + colList.size());
for (int i = 0; i < colList.size(); i++) {
String aCol = (String)colList.get(i);
String colstring = normalizeCollectionURI(aCol, (String) table.get(XMLTools.LOCAL));
col = DatabaseManager.getCollection(colstring);
System.out.println("colstring=" + colstring);
if (col == null) {
System.out.println("ERROR : Collection not found!");
return false;
}
service = (XPathQueryService) col.getService("XPathQueryService", "1.0");
addNamespaces(service, (String) table.get("namespaces"));
ResourceSet resultSet = service.query(querystring);
results = resultSet.getIterator();
while (results.hasMoreResources()) {
XMLResource resource = (XMLResource) results.nextResource();
String documentstr = (String) resource.getContent();
System.out.println(documentstr);
}
}
} catch (Exception e) {
System.out.println("ERROR : " + e.getMessage());
if (table.get(XMLTools.VERBOSE).equals("true")) {
if (log.isWarnEnabled()) {
log.warn("ignored exception", e);
}
}
return false;
} finally {
if (col != null) {
col.close();
}
}
return true;
}
private void addNamespaces(XPathQueryService service, String namespacesString) throws XMLDBException {
if ((namespacesString != "") && (namespacesString != null)) {
StringTokenizer st = new StringTokenizer(namespacesString, "=;");
if (st.countTokens() % 2 != 0) {
System.out.println("ERROR : mismatched namespace prefixes and uris");
return;
}
while (st.hasMoreTokens()) {
service.setNamespace(st.nextToken(), st.nextToken());
}
}
}
private void getCollectionList(Hashtable table, ArrayList workTable) {
String col = (String) table.get(XMLTools.COLLECTION);
StringTokenizer tok = new StringTokenizer(col, ";, ");
for (int i = 0; tok.hasMoreTokens(); i++) {
workTable.add(tok.nextToken());
}
expandColStr(table, workTable);
}
private void expandColStr(Hashtable table, ArrayList workTable) {
for (int i = 0; i < workTable.size(); i++) {
String argStr = (String)workTable.get(i);
int starPos = argStr.indexOf("/*");
if (starPos > 0) {
String head = argStr.substring(0, starPos);
String tail = argStr.substring(starPos + 2);
String[] children = getChildCollections(table, head);
if (children != null && children.length > 0) {
workTable.remove(i);
for (int j = 0; j < children.length; j++) {
workTable.add(head + "/" + children[j] + tail);
}
expandColStr(table, workTable);
}
}
}
}
private String[] getChildCollections(Hashtable table, String parent) {
Collection coll = null;
String[] colarray = null;
String colstring = normalizeCollectionURI(parent,
(String) table.get(XMLTools.LOCAL));
try {
coll = DatabaseManager.getCollection(colstring);
if (coll != null) {
colarray = coll.listChildCollections();
}
}
catch (XMLDBException ex) {
}
finally {
if (coll != null) {
try {
coll.close();
}
catch (XMLDBException ex) {
}
}
}
return colarray;
}
}
