/*
* eXist Open Source Native XML Database
* Copyright (C) 2001-2011 The eXist Project
* http://exist-db.org
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser 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 Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser 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.
*
* $Id$
*/
package org.exist.xquery.functions.session;
//import org.apache.log4j.Logger;
import org.exist.dom.QName;
import org.exist.http.servlets.SessionWrapper;
import org.exist.xquery.Cardinality;
import org.exist.xquery.Function;
import org.exist.xquery.FunctionSignature;
import org.exist.xquery.Variable;
import org.exist.xquery.XPathException;
import org.exist.xquery.XPathUtil;
import org.exist.xquery.XQueryContext;
import org.exist.xquery.value.FunctionParameterSequenceType;
import org.exist.xquery.value.FunctionReturnSequenceType;
import org.exist.xquery.value.Item;
import org.exist.xquery.value.JavaObjectValue;
import org.exist.xquery.value.Sequence;
import org.exist.xquery.value.SequenceType;
import org.exist.xquery.value.Type;
/**
* Returns an attribute stored in the current session or an empty sequence
* if the attribute does not exist.
*
* @author Wolfgang Meier
* @author Loren Cahlander
*/
public class GetAttribute extends Function
{
// private static final Logger logger = Logger.getLogger(GetAttribute.class);
public final static FunctionSignature signature =
new FunctionSignature(
new QName( "get-attribute", SessionModule.NAMESPACE_URI, SessionModule.PREFIX ),
"Returns an attribute stored in the current session object or an empty sequence " +
"if the attribute cannot be found.",
new SequenceType[] {
new FunctionParameterSequenceType( "name", Type.STRING, Cardinality.EXACTLY_ONE, "The session attribute name" )
},
new FunctionReturnSequenceType( Type.ITEM, Cardinality.ZERO_OR_MORE, "the attribute value" ) );
public GetAttribute( XQueryContext context )
{
super( context, signature );
}
/* (non-Javadoc)
* @see org.exist.xquery.Expression#eval(org.exist.dom.DocumentSet, org.exist.xquery.value.Sequence, org.exist.xquery.value.Item)
*/
public Sequence eval( Sequence contextSequence, Item contextItem ) throws XPathException
{
final SessionModule myModule = (SessionModule)context.getModule(SessionModule.NAMESPACE_URI);
// session object is read from global variable $session
final Variable var = myModule.resolveVariable( SessionModule.SESSION_VAR );
if( var == null || var.getValue() == null ) {
// throw( new XPathException( this, "Session not set" ) );
return( Sequence.EMPTY_SEQUENCE );
}
if( var.getValue().getItemType() != Type.JAVA_OBJECT ) {
throw( new XPathException( this, "Variable $session is not bound to a Java object." ) );
}
final JavaObjectValue session = (JavaObjectValue)var.getValue().itemAt( 0 );
// get attribute name parameter
final String attribName = getArgument( 0 ).eval( contextSequence, contextItem ).getStringValue();
if( session.getObject() instanceof SessionWrapper ) {
try {
final Object o = ( (SessionWrapper)session.getObject() ).getAttribute( attribName );
if( o == null ) {
return( Sequence.EMPTY_SEQUENCE );
}
return( XPathUtil.javaObjectToXPath( o, context ) );
}
catch( final IllegalStateException ise ) {
//TODO: if we throw an exception here it means that getAttribute()
//cannot be called after invalidate() on the session object. This is the
//way that it works in Java, however this isnt the way it works in xquery currently
//we can change this but we need to be aware of the consequences, the eXist admin webapp is a
//good example of what happens if you change this - try logging out of the webapp ;-)
// - deliriumsky
//log.error(ise.getStackTrace());
//throw new XPathException(this, "Session has an IllegalStateException for getAttribute() - " + ise.getStackTrace() + System.getProperty("line.separator") + System.getProperty("line.separator") + "Did you perhaps call session:invalidate() previously?");
return( Sequence.EMPTY_SEQUENCE );
}
} else {
throw( new XPathException( this, "Type error: variable $session is not bound to a session object" ) );
}
}
}