package vin.jar;
/**

	Saturday, February 17, 2001
	Manipulate jar (and zip) files programmatically

	----------------------------------------------

	What do we want?
	1. create new empty jarfile (easy)
		public static File create(String path)
	2. add entry to this file
		public static void add(File jarFile,  File jarEntryFile)
	3. delete entry from this file (work in progress)
		public static void delete(File jarFile,  File jarEntry)
	4. update an entry in this file (work in progress)
		public static void update(File jarFile,  File jarEntry)
	5. get an entry (work in progress)
		public static File get(File jarFile,  String jarEntryName)
	
*/


import java.io.*;
import java.util.jar.*;
import java.util.zip.*;


class Jar{
	/*	testfile:  test1.txt
	*/
	static String testFilePath ="src/vin/jar";

	public static void main( String args[] ){
	
		//create new empty jarfile
		File jarFile = create(testFilePath + "/" + "test.jar"); 
	
		//add entry to this file
		try{
			File jarEntryFile = new File( testFilePath + "/" +  "test1.txt" );
			add(jarFile, jarEntryFile );
		} catch (Exception ioe){
			System.out.println("Error creating jarEntryFile in main()");
			ioe.printStackTrace();
		}
	}
	 /** Adds a file to a jar file */
	public static void add(File jarFile,  File jarEntryFile){
		String name =null;
		try{
			// open jos to jar file
			JarOutputStream	jos = new JarOutputStream( new FileOutputStream(jarFile) );

			// read bytes of file to be jarred
			long len = jarEntryFile.length(); 
			byte ar[] = new byte[(int) len];
			System.out.println("Entry-length before  jar=" + len);
			DataInputStream dis = new DataInputStream( new FileInputStream(jarEntryFile));
			dis.readFully( ar, 0, ar.length); 

			// create new jar entry
			// ie include path to the file name, like:
			//name = aRelativePath + "/" + jarEntryFile.getName(); 
			name  = jarEntryFile.getName();
			JarEntry jarEntry = new JarEntry( name );

			// put into jar file 
			jos.putNextEntry( jarEntry );

			// write bytes to open entry of jar file
			jos.write( ar, 0, ar.length);
			// close jos
			jos.close();
		} catch (Exception ioe){
			System.out.println("IOError writing to jarfile");
			ioe.printStackTrace();
		}
	}

	/** Creates new empty jarfile or overwrites existing one */
	public static File create(String path){
		File jarFile=null;
		try{
			jarFile = new File( path );
 			JarOutputStream	jos = new JarOutputStream( new FileOutputStream(jarFile) );
		} catch (Exception ioe){
			System.out.println("Error creating jarfile");
			ioe.printStackTrace();
		}
		
		return jarFile;
	}

	public static File get(File file,  String jarEntryName){
		if((null==jarEntryName) || (jarEntryName.length()<1) ){
			System.out.println("Error Jar.get() - received invalid jar entry name with 2nd argument");
			return null;
		}
		
		if ( (null==file) || (!file.exists()) ){
			System.out.println("Error Jar.get() - received invalid file with 1st argument");
			return null;
		}

		File jarEntryFile=null;
		JarInputStream jis =null;
		ZipEntry je=null; //JarEntry je = null;
		
		try{
			
			jis = new JarInputStream( new FileInputStream(file) );
			if ( (null==jis) || (0==jis.available())){
				System.out.println("Error Jar.get() - could not get valid JarInputStream from " + file.getName());
				return null;
			}

			JarFile jf = new JarFile(file); 
			je = jf.getEntry(jarEntryName) ;
  			long len = je.getSize(); //the uncompressed size of the entry data, or -1 if not known
			InputStream is = jf.getInputStream(je); // positions cursor at 1st byte of je
			jis = new JarInputStream(is);
			byte ar[]  = new byte[(int) len];
			jis.read(ar, 0, ar.length);
			System.out.println("Array length:" + ar.length);
	
			/*in progress:
				file has invalid byte format,
				use different File/IO
				find out 
			*/	
			RandomAccessFile raf = new RandomAccessFile(je.getName(), "rw");
			//raf.write(ar, 0, ar.length); 
			raf.writeChars( new String(ar,"UTF-8")); 

			
			raf.close();
		
        } catch(IOException ioe){
			System.out.println("Error getting entry from jarEntryFile in get()");
			ioe.printStackTrace(System.out);
        
        } catch (Exception e){
			System.out.println("Error (unforeseen) getting entry from jarEntryFile in get()");
			e.printStackTrace(System.out);
        } finally{
        	try{
        		if (null!=jis) jis.close();
        	} catch (Throwable t){}
        
        }
	
		
		return jarEntryFile;
	}




	// to be implemented yet
	// -------------------------------------
	// -------------------------------------
	public static void delete(File jarFile,  File jarEntry){
	}

	public static void update(File jarFile,  File jarEntry){
	}

}