001    /*
002            Copyright (c) 2009 Olivier Chafik, All Rights Reserved
003            
004            This file is part of JNAerator (http://jnaerator.googlecode.com/).
005            
006            JNAerator is free software: you can redistribute it and/or modify
007            it under the terms of the GNU Lesser General Public License as published by
008            the Free Software Foundation, either version 3 of the License, or
009            (at your option) any later version.
010            
011            JNAerator is distributed in the hope that it will be useful,
012            but WITHOUT ANY WARRANTY; without even the implied warranty of
013            MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
014            GNU Lesser General Public License for more details.
015            
016            You should have received a copy of the GNU Lesser General Public License
017            along with JNAerator.  If not, see <http://www.gnu.org/licenses/>.
018    */
019    package com.ochafik.lang.jnaerator.runtime.globals;
020    
021    import com.sun.jna.Callback;
022    import com.sun.jna.CallbackReferenceHack;
023    import com.sun.jna.NativeLibrary;
024    
025    public class GlobalCallback<T extends Callback> extends Global {
026            protected final Class<T> type;
027            public GlobalCallback(NativeLibrary library, Class<T> type, String... symbols) {
028                    super(library, symbols);
029                    this.type = type;
030            }
031            protected T value;
032            @SuppressWarnings("unchecked")
033            public T get() {
034                    if (value == null) {
035                            value = (T)CallbackReferenceHack.getCallback(type, getPointer());
036                    }
037                    return value;
038            }
039            public void set(T value) {
040                    getPointer().setPointer(0, CallbackReferenceHack.getFunctionPointer(this.value = value));
041            }
042            
043            @Override
044            public String toString() {
045                    try {
046                            return String.valueOf(getClass().getMethod("get").invoke(this));
047                    } catch (Throwable t) {
048                            return super.toString();
049                    }
050            }
051    }