fiore@3: /*  
fiore@3:  CCmI Editor - A Collaborative Cross-Modal Diagram Editing Tool
fiore@3:   
fiore@3:  Copyright (C) 2011  Queen Mary University of London (http://ccmi.eecs.qmul.ac.uk/)
fiore@3: 
fiore@3:  This program is free software: you can redistribute it and/or modify
fiore@3:  it under the terms of the GNU General Public License as published by
fiore@3:  the Free Software Foundation, either version 3 of the License, or
fiore@3:  (at your option) any later version.
fiore@3: 
fiore@3:  This program is distributed in the hope that it will be useful,
fiore@3:  but WITHOUT ANY WARRANTY; without even the implied warranty of
fiore@3:  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
fiore@3:  GNU General Public License for more details.
fiore@3: 
fiore@3:  You should have received a copy of the GNU General Public License
fiore@3:  along with this program.  If not, see <http://www.gnu.org/licenses/>.
fiore@3: */  
fiore@3: 
fiore@3: package uk.ac.qmul.eecs.ccmi.utils;
fiore@3: 
fiore@3: import java.io.File;
fiore@3: import java.io.FileOutputStream;
fiore@3: import java.io.IOException;
fiore@3: import java.io.InputStream;
fiore@3: import java.net.URL;
fiore@3: 
fiore@3: /**
fiore@3:  * This class is used to extract a native library (e.g. .dll file in windows) from within a jar 
fiore@3:  * to the local file system, in order to allow the virtual machine to load it.
fiore@3:  *
fiore@3:  */
fiore@3: public class ResourceFileWriter {
fiore@3: 	
fiore@3: 	/**
fiore@3: 	 * Creates an instance of the the class linked to a native library file.
fiore@3: 	 * @param resource the URL of the native library file. The URL can be obtained by  
fiore@3: 	 * @see Class#getResource(String), therefore can be called from a class within a jar file
fiore@3: 	 * which needs to access a static library.  
fiore@3: 	 */
fiore@3: 	public ResourceFileWriter(URL resource){
fiore@3: 		this.resource = resource;
fiore@3: 	}
fiore@3: 	
fiore@3: 	public void serResource(URL resource){
fiore@3: 		this.resource = resource;;
fiore@3: 		path = null;
fiore@3: 	}
fiore@3: 
fiore@3: 	/**
fiore@3: 	 * Writes the file in a directory returned by {@link PreferencesService#get(String, String)}} if defined, or 
fiore@3: 	 * the System default temporary directory otherwise. 
fiore@3: 	 * The path to the file can be retrieved by @see {@link #getFilePath()} and then passed as argument 
fiore@3: 	 * to {@link System#load(String)} 
fiore@3: 	 * 
fiore@3: 	 * @param prefix a prefix the temporary native library file will have in the temporary directory  
fiore@3: 	 */
fiore@3: 	public void writeToDisk(String dir,String fileName){
fiore@3: 		if (resource == null) 
fiore@3: 			return;
fiore@3: 		InputStream in = null;
fiore@3: 		FileOutputStream out = null;
fiore@3: 		File file = new File(dir,fileName);
fiore@3: 		if(file.exists()){ //if file already exists. no job needs to be done.
fiore@3: 			path = file.getAbsolutePath();
fiore@3: 			return;
fiore@3: 		}
fiore@3: 		try{
fiore@3: 			in = resource.openStream();
fiore@3: 			out = new FileOutputStream(file);
fiore@3: 			int byteRead;
fiore@3: 			byte[] b = new byte[1024];
fiore@3: 			while((byteRead = in.read(b)) > 0){
fiore@3: 				out.write(b, 0, byteRead);
fiore@3: 			}
fiore@3: 			path = file.getAbsolutePath();
fiore@3: 		}catch(IOException ioe){
fiore@3: 			path = null;
fiore@3: 		}finally{
fiore@3: 			if(in != null) 
fiore@3: 				try{in.close();}catch(IOException ioe){}
fiore@3: 			if(out != null) 
fiore@3: 				try{out.close();}catch(IOException ioe){}	
fiore@3: 		}
fiore@3: 		
fiore@3: 	}
fiore@3: 	
fiore@3: 	/**
fiore@3: 	 * Returns the absolute path of the last written file. If the writing wasn't successfully 
fiore@3: 	 * or no writing took place yet, then {@code null} is returned. 
fiore@3: 	 * @return the path of the last written file or {@code null}
fiore@3: 	 */
fiore@3: 	public String getFilePath(){
fiore@3: 		return path;
fiore@3: 	}
fiore@3: 	
fiore@3: 	private URL resource;
fiore@3: 	private String path;
fiore@3: }