What is the DoubleBuffer equals() method in Java?
The equals() method of the class java.nio.DoubleBuffer is used to check if two buffers are equal or not. Two buffers are equal if:
- They have the same type of elements
- They have the same number of elements
- They have the same sequence of remaining elements
Note:
- Unlike
Double.equals(Object), -0.0 and +0.0 are considered equal by theDoubleBuffer.equals()method.- Two doubles f1 and f2 are considered equal by
DoubleBuffer.equals()method if (f1 == f2) || (Double.isNaN(f1) && Double.isNaN(f2)).
Declaration
The DoubleBuffer.equals() method can be declared as:
buff1.equals(buff2);
buff1: The first buffer checked to see if it is equal tobuff2.buff2: The second buffer checked to see if it is equal tobuff1.
Return value
The DoubleBuffer.equals() method returns a boolean such that:
- The return value is
trueif the two buffersbuff1andbuff2are equal. - The return value is
falseif the two buffersbuff1andbuff2are notequal.
Examples
Example1
Consider the code snippet below, which demonstrates the use of the DoubleBuffer.equals() method:
import java.nio.*;import java.util.*;public class main {public static void main(String[] args) {int n1 = 4;int n2 = 4;try {DoubleBuffer buff1 = DoubleBuffer.allocate(n1);buff1.put(1.5);buff1.put(4.6);System.out.println("buff1: " + Arrays.toString(buff1.array()));DoubleBuffer buff2 = DoubleBuffer.allocate(n2);buff2.put(1.5);buff2.put(4.6);System.out.println("buff2: " + Arrays.toString(buff2.array()));boolean foo = buff1.equals(buff2);System.out.println("\nbuff1 equal to buff2: " + foo);} catch (IllegalArgumentException e) {System.out.println("Error!!! IllegalArgumentException");} catch (ReadOnlyBufferException e) {System.out.println("Error!!! ReadOnlyBufferException");}}}
Explanation
- A
DoubleBufferbuff1is declared in line 8. Two doubles are written tobuff1in lines 9-10. - A
DoubleBufferbuff2is declared in line 13. Two doubles are written tobuff2in lines 14-15. - The
DoubleBuffer.equals()method is used in line 18 to check if the buffersbuff1andbuff2are equal. TheDoubleBuffer.equals()method returnstruebecausebuff1andbuff2are equal.
Example 2
Consider the code snippet below, which compares two unequal buffers:
import java.nio.*;import java.util.*;public class main {public static void main(String[] args) {int n1 = 4;int n2 = 5;try {DoubleBuffer buff1 = DoubleBuffer.allocate(n1);buff1.put(1.5);buff1.put(4.6);System.out.println("buff1: " + Arrays.toString(buff1.array()));DoubleBuffer buff2 = DoubleBuffer.allocate(n2);buff2.put(1.5);buff2.put(4.6);System.out.println("buff2: " + Arrays.toString(buff2.array()));boolean foo = buff1.equals(buff2);System.out.println("\nbuff1 equal to buff2: " + foo);} catch (IllegalArgumentException e) {System.out.println("Error!!! IllegalArgumentException");} catch (ReadOnlyBufferException e) {System.out.println("Error!!! ReadOnlyBufferException");}}}
Explanation
- A
DoubleBufferbuff1is declared in line 8. Two doubles are written tobuff1in lines 9-10. - A
DoubleBufferbuff2is declared in line 13. Two doubles are written tobuff2in lines 14-15. - The
DoubleBuffer.equals()method is used in line 18 to check if the buffersbuff1andbuff2are equal. TheDoubleBuffer.equals()method returnsfalsebecause the number of elements ofbuff1is 4 and the number of elements ofbuff2is 5, which is not equal.
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