PackingCharacters.java

package ch01basic;

import static java.lang.Long.toHexString;

public class PackingCharacters {
    public static void main(String[] args) {
        char letterA = 'A';
        char letterB = 'B';
        char letterC = 'C';
        char letterD = 'D';
        long packed = 0L;
        packed = letterD;                                                  // Store D
        packed = (packed << 16) | letterC;                                 // Shift and add the next letter - C
        packed = (packed << 16) | letterB;                                 // Shift and add the next letter - B
        packed = (packed << 16) | letterA;                                 // Shift and add the next letter - A
        System.out.println("packed now contains 0x" + toHexString(packed));

        // Now unpack the letters and output them
        long mask = 0xFFFF;                                                // Rightmost 16 bits as 1
        char letter = (char) (packed & mask);                               // Extract the rightmost letter
        System.out.println("From right to left the letters in packed are:");
        System.out.println("  " + letter + "  0x" + toHexString(letter));
        packed >>= 16;                                                     // Shift out the rightmost letter
        letter = (char) (packed & mask);                                    // Extract the new rightmost letter
        System.out.println("  " + letter + "  0x" + toHexString(letter));
        packed >>= 16;                                                     // Shift out the rightmost letter
        letter = (char) (packed & mask);                                    // Extract the new rightmost letter
        System.out.println("  " + letter + "  0x" + toHexString(letter));
        packed >>= 16;                                                     // Shift out the rightmost letter
        letter = (char) (packed & mask);                                    // Extract the new rightmost letter
        System.out.println("  " + letter + "  0x" + toHexString(letter));
    }
}