/*
 * FileObjectIdentity.java
 *
 * Created on February 19, 2003, 12:40 PM
 */

package org.openide.filesystems;

import java.beans.*;
import java.util.*;
import org.openide.util.*;

/**
 *
 * @author  rm111737
 */
final public class FileObjectIdentity {
    public static final String PROP_IDENTITY_CHANGE = "identityChange"; // NOI18N    
    
    private static Map identityMap;
    private FileObject fo;
    private FileChangeListener fsListener;
    private PropertyChangeSupport changeSupport;

    private FileObjectIdentity() {}
    
    /** Creates a new instance of FileObjectIdentity */
    private FileObjectIdentity(FileObject fo) {
        this.fo = fo;
    }
    
    /** 
     * @param fo
     * @return FileObjectIdentity or null if there is no guarantee, that identity
     * can be succesfully kept.
     */    
    static public FileObjectIdentity getFileObjectIdentity (FileObject fo) {                
        FileObjectIdentity retVal = null; 
        boolean guarantee = ((fo instanceof AbstractFileObject) || 
        (fo instanceof MultiFileObject));
        if (guarantee) {            
            synchronized (FileObjectIdentity.class) {
                if (identityMap == null) {
                    identityMap = new WeakHashMap ();
                }
                retVal = (FileObjectIdentity)identityMap.get(fo);
                if (retVal == null) {
                    retVal = new FileObjectIdentity (fo);
                    identityMap.put(retVal.fo, retVal);
                    //retVal.initListener (fo);
                }
            }
        }
        return retVal;
    }

    public FileObject getFileObject () {
        return fo;
    }
    
    public final void addPropertyChangeListener(PropertyChangeListener listener) {
        synchronized (FileObjectIdentity.class) {
            if (changeSupport == null)
                changeSupport = new PropertyChangeSupport(this);
        }
        changeSupport.addPropertyChangeListener(listener);
    }
    
    public final void removePropertyChangeListener(PropertyChangeListener listener) {
        if (changeSupport != null)
            changeSupport.removePropertyChangeListener(listener);
    }
    
    
    static void moveNotify (FileObject oldInstance, FileObject newInstance) {        
        synchronized (FileObjectIdentity.class) {
            FileObjectIdentity identity = (FileObjectIdentity)identityMap.get(oldInstance);
            if (identity != null) {
                identity.changeIdentity (newInstance);
                identityMap.remove(oldInstance);
                identityMap.put(newInstance, identity);                
            }            
        }
    }
    
    private void changeIdentity (FileObject fo) {
        FileObject oldInstance = this.fo;
        FileObject newInstance = fo;
        //reInitListener (oldInstance, newInstance);
        this.fo = fo;
        if (changeSupport != null)
            changeSupport.firePropertyChange(PROP_IDENTITY_CHANGE, oldInstance, newInstance);
    }    

}