/**

  * HTML via Java(tm) Language Bindings

  * Copyright (C) 2013 Jaroslav Tulach <jaroslav.tulach@apidesign.org>

  *

  * This program 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, version 2 of the License.

  *

  * 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 General Public License for more details. apidesign.org

  * designates this particular file as subject to the

  * "Classpath" exception as provided by apidesign.org

  * in the License file that accompanied this code.

  *

  * You should have received a copy of the GNU General Public License

  * along with this program. Look for COPYING file in the top folder.

  * If not, see http://wiki.apidesign.org/wiki/GPLwithClassPathException

  */

 package org.apidesign.html.boot.impl;

 import java.io.Closeable;

 import java.io.IOException;

 import java.util.logging.Logger;

 import org.apidesign.html.boot.spi.Fn;

 /**

  *

  * @author Jaroslav Tulach <jtulach@netbeans.org>

  */

 public final class FnContext implements Closeable {

     private static final Logger LOG = Logger.getLogger(FnContext.class.getName());

     private Object prev;

     private FnContext(Fn.Presenter p) {

         this.prev = p;

     }

     @Override

     public void close() throws IOException {

         if (prev != this) {

             currentPresenter((Fn.Presenter)prev);

             prev = this;

         }

     }

 /*

     @Override

     protected void finalize() throws Throwable {

         if (prev != null) {

             LOG.warning("Unclosed context!");

         }

     }

 */

     public static Closeable activate(Fn.Presenter newP) {

         return new FnContext(currentPresenter(newP));

     }

     private static final ThreadLocal<Fn.Presenter> CURRENT = new ThreadLocal<Fn.Presenter>();

     public static Fn.Presenter currentPresenter(Fn.Presenter p) {

         Fn.Presenter prev = CURRENT.get();

         CURRENT.set(p);

         return prev;

     }

     public static Fn.Presenter currentPresenter() {

         Fn.Presenter p = CURRENT.get();

         if (p == null) {

             throw new IllegalStateException("No current WebView context around!");

         }

         return p;

     }

 }