com.coi.tools.os.izpack.COIOSHelper Maven / Gradle / Ivy
/*
* $Id: COIOSHelper.java 2163 2008-05-18 13:48:36Z jponge $
* IzPack - Copyright 2001-2008 Julien Ponge, All Rights Reserved.
*
* http://izpack.org/
* http://izpack.codehaus.org/
*
* Copyright 2005 Klaus Bartz
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.coi.tools.os.izpack;
import com.izforge.izpack.util.Librarian;
import com.izforge.izpack.util.NativeLibraryClient;
/**
* Base class to handle multiple native methods of multiple classes in one shared library. This is a
* singelton class.
*
* @author Klaus Bartz
*/
public class COIOSHelper
{
private static COIOSHelper self = null;
private static int used = 0;
private static boolean destroyed = false;
private boolean failed = false;
/**
* This method is used to free the library at the end of progam execution. After this call, any
* instance of this class will not be usable any more!
*
* @param name the name of the library to free. Use only the name and extension but not the
* path.
*/
private native void FreeLibrary(String name);
/**
* Default constructor, do not use
*/
private COIOSHelper()
{
super();
}
/**
* Returns the one existent object of this class.
*
* @return the one existent object of this class
*/
public static synchronized COIOSHelper getInstance()
{
if (self == null)
{
self = new COIOSHelper();
}
return (self);
}
/*--------------------------------------------------------------------------*/
/**
* This method is used to free the library at the end of progam execution. This is the method of
* the helper class which will be called from other objects. After this call, any instance of
* this class will not be usable any more! Note that this method does NOT return
* at the first call, but at any other
*
* DO NOT CALL THIS METHOD DIRECTLY!
* It is used by the librarian to free the native library before physically deleting it from its
* temporary loaction. A call to this method will freeze the application irrecoverably!
*
* @param name the name of the library to free. Use only the name and extension but not the
* path.
*
* @see com.izforge.izpack.util.NativeLibraryClient#freeLibrary
*/
/*--------------------------------------------------------------------------*/
/**
* @param name
*/
public void freeLibrary(String name)
{
used--;
if (!destroyed)
{
FreeLibrary(name);
destroyed = true;
}
}
/**
* Add a NativeLibraryClient as dependant to this object. The method tries to load the shared
* library COIOSHelper which should contain native methods for the dependant.
*
* @param dependant to be added
* @throws Exception if loadLibrary for the needed lib fails
*/
public void addDependant(NativeLibraryClient dependant) throws Exception
{
used++;
if (failed)
{
throw (new Exception("load native library failed"));
}
try
{
Librarian.getInstance().loadLibrary("COIOSHelper", dependant);
}
catch (UnsatisfiedLinkError exception)
{
failed = true;
throw (new Exception("could not locate native library"));
}
catch (Throwable t)
{
failed = true;
throw (new Exception(t));
}
}
}