/*
BEGIN LICENSE BLOCK
Copyright 2010-2011, Heiko Mueller, Sam Lindley, James Cheney and
University of Edinburgh
This file is part of Database Wiki.
Database Wiki 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 3 of the License, or
(at your option) any later version.
Database Wiki 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 Database Wiki. If not, see <http://www.gnu.org/licenses/>.
END LICENSE BLOCK
*/
package org.dbwiki.data.query;
import org.dbwiki.data.database.Database;
import org.dbwiki.exception.data.WikiQueryException;
/** An interface for QueryStatements
* These are either nodeid queries or path queries
* Methods allow distinguishing the two cases.
* FIXME #query: Provide query-related behaviors in appropriate subclasses.
*
* @author jcheney
*
*/
public abstract class QueryStatement {
/*
* Public Constants
*/
//
// N(ode) ID expression, i.e., nid://<<node-id>>
//
// <<node-id>>: hexadecimal integer value
//
public static final String QueryNID = "nid";
//
// XPATH-like expression (called Wiki-Path), i.e., wpath://<<schema-node-name>>{[<<child-path>>='...'] | :<<node-index>>}/...
//
public static final String QueryWikiPath = "wpath";
/*
* Interface Methods
*/
public abstract QueryResultSet execute() throws org.dbwiki.exception.WikiException;
public static QueryStatement createStatement(Database database, String query) throws org.dbwiki.exception.WikiException {
if (query != null) {
if (query.toLowerCase().startsWith(QueryStatement.QueryNID.toLowerCase() + "://")) {
return new NIDQueryStatement(database, query.substring(QueryStatement.QueryNID.length() + 3));
} else if (query.toLowerCase().startsWith(QueryStatement.QueryWikiPath.toLowerCase() + "://")) {
return new WikiPathQueryStatement(database, query.substring(QueryStatement.QueryWikiPath.length() + 2));
} else if (query.toLowerCase().startsWith("select ")) {
return new XAQLQueryStatement(database, query);
} else {
throw new WikiQueryException(WikiQueryException.UnknownQueryFormat, query);
}
} else {
throw new WikiQueryException(WikiQueryException.InvalidQueryFormat, "(null)");
}
}
}