/*
 * Javolution - Java(TM) Solution for Real-Time and Embedded Systems
 * Copyright (C) 2012 - Javolution (http://javolution.org/)
 * All rights reserved.
 * 
 * Permission to use, copy, modify, and distribute this software is
 * freely granted, provided that this notice is preserved.
 */
package javolution.context.internal;

import javolution.context.SecurityContext;
import javolution.util.FastTable;

/**
 * Holds the default implementation of SecurityContext.
 */
public final class SecurityContextImpl extends SecurityContext {

    private FastTable<Action> actions = new FastTable<Action>();

    @Override
    public boolean isGranted(Permission<?> permission) {
        boolean isGranted = true;
        for (Action a : actions) {
            if (a.permission.implies(permission))
                isGranted = a.grant;
        }
        return isGranted;
    }

    @Override
    public void grant(Permission<?> permission, Object certificate)
            throws SecurityException {
        Action a = new Action();
        a.grant = true;
        a.permission = permission;
        actions.add(a);
    }

    @Override
    public void revoke(Permission<?> permission, Object certificate)
            throws SecurityException {
        Action a = new Action();
        a.grant = false;
        a.permission = permission;
        actions.add(a);
    }

    @Override
    protected SecurityContext inner() {
        SecurityContextImpl ctx = new SecurityContextImpl();
        ctx.actions.addAll(actions);
        return ctx;
    }

    // Represents the grant/revoke action performed. 
    private static class Action {
        boolean grant; // Else revoke.
        Permission<?> permission;
    }
}