Deflater needsInput() function in Java with examples

The needsInput() function of the Deflater class in java.util.zip is used to check if the input data buffer is empty. If the input data buffer is empty then setInput() function is called to provide input

Function Signature:

public boolean needsInput()

Syntax:

d.needsInput();

Parameter: The function requires no parameter

Return Type: The function returns a boolean value i.e. it returns true if the input buffer empty else returns false.

Exception: The function does not throw any exception

Example 1:

// Java program to describe the use
// of needsInput() function

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

class GFG {
    public static void main(String args[])
        throws UnsupportedEncodingException
    {
        // deflater
        Deflater d = new Deflater();

        // get the text
        String pattern = "GeeksforGeeks", text = "";

        // generate the text
        for (int i = 0; i < 4; i++)
            text += pattern;

        // set the Input for deflator
        d.setInput(text.getBytes("UTF-8"));

        // finish
        d.finish();

        // output bytes
        byte output[] = new byte[1024];

        // does the deflater need input
        System.out.println("Input Buffer Empty ? :"
                           + d.needsInput());

        // compress the data
        int size = d.deflate(output);

        // compressed String
        System.out.println("Compressed String :"
                           + new String(output)
                           + "\n Size " + size);

        // original String
        System.out.println("Original String :"
                           + text + "\n Size "
                           + text.length());

        // does the deflater need input
        System.out.println("Input Buffer Empty ? :"
                           + d.needsInput());

        // end
        d.end();
    }
}

Output:

Input Buffer Empty ? :false
Compressed String :x?sOM?.N?/r???q??
 Size 21
Original String :GeeksforGeeksGeeksforGeeksGeeksforGeeksGeeksforGeeks
 Size 52
Input Buffer Empty ? :true

Reference: https://docs.oracle.com/javase/7/docs/api/java/util/zip/Deflater.html#needsInput()