/*
* eXist Open Source Native XML Database
* Copyright (C) 2001-2015 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.
*/
package org.exist.xquery;
import org.exist.security.Subject;
/**
* Base class for XQuery functions which switch the current user
*
* Provides the function {@link #switchUser(Subject)} to allow us
* to switch the current broker to a user and then have it switched
* back when the XQuery expression is reset
*
* @author Adam Retter <adam.retter@googlemail.com>
*/
public abstract class UserSwitchingBasicFunction extends BasicFunction {
/**
* Flag which indicates that we have pushed a subject and so we must later
* pop the subject when the expression is reset, see {@link UserSwitchingBasicFunction#resetState(boolean)}
*/
private boolean pushedSubject = false;
public UserSwitchingBasicFunction(final XQueryContext context, final FunctionSignature signature) {
super(context, signature);
}
/**
* Switches the current broker to the provided user
*
*/
protected void switchUser(final Subject user) {
context.getBroker().pushSubject(user);
pushedSubject = true;
}
/**
* Takes care to switch the broker back from the switched
* user before calling @{link super#resetState(boolean)}
*/
@Override
public void resetState(final boolean postOptimization) {
//if we pushed a subject, we must pop it
if(this.pushedSubject) {
try {
context.getBroker().popSubject();
} finally {
this.pushedSubject = false;
}
}
super.resetState(postOptimization);
}
}