WizCrypt API Guide--Callback

Often when doing IO operations it is recommended that the user be given the feedback (progress) of the operation. For writing applications that display GUI elements like progress bar for showing the progress made by WizCrypt, the Callback API is used.

org.wiztools.wizcrypt.Callback Interface

For writing applications that display progress of encryption/decryption operation, one has to write a class implementing the Callback interface.

package org.wiztools.wizcrypt;

public interface Callback {

    public void begin();
    
    public void notifyProgress(long value);
    
    public void end();
}

An Example

Let us write a simple console based progress monitor. When the encryption/decryption operation starts, we need to print "Begin", then print the number of bytes processed as the operation proceeds, and finally print "End" as the operation ends.

For this, we will be writing a class like this:

class TestCallback implements org.wiztools.wizcrypt.Callback {
    public void begin() {
        System.out.println("~~~~ Callback output ~~~~");
        System.out.print("Begin,");
    }

    public void notifyProgress(long value) {
        System.out.print(value + ",");
    }

    public void end() {
        System.out.println("End.\n");
    }

}

Simple? Now to actually use this class:

 import org.wiztools.wizcrypt.Callback;
 import org.wiztools.wizcrypt.WizCrypt;
 import java.io.*;

 // ...
 File myFile = new File("a.jpg");
 InputStream is = new FileInputStream(myFile);
 OutputStream os = new FileOutputStream("a.jpg.wiz");
 CipherKey ck = CipherKeyGen.getCipherKeyForEncrypt("password");
 Callback cb = new TestCallback();
 WizCrypt.encrypt(is, os, ck, cb);

Output:

~~~~ Callback output ~~~~
Begin,512,1024,1536,2048,2560,3072,3584,4096,4608,5120,5632,6144,6656,7168,7680,
8192,8704,9216,9728,10240,10752,11264,11776,11848,End.

Now, if instead of printing the number of bytes processed, if you want to print the % progress, you would change the last line in the above code to:

 long size = myFile.length();
 WizCrypt.encrypt(is, os, ck, cb, size);

Output:

~~~~ Callback output ~~~~
Begin,4,8,12,17,21,25,30,34,38,43,47,51,56,60,64,69,73,77,82,86,90,95,99,100,End.

Refer to JavaDocs for API documentation.