DoubleStream allMatch() in Java with examples

DoubleStream allMatch(DoublePredicate predicate) returns whether all elements of this stream match the provided predicate. It may not evaluate the predicate on all elements if not necessary for determining the result. This is a short-circuiting terminal operation. A terminal operation is short-circuiting if, when presented with infinite input, it may terminate in finite time.
Syntax :

boolean allMatch(DoublePredicate predicate)

Parameters :

1. DoublePredicate : A predicate (boolean-valued function) of one double-valued argument.

Return Value : The function returns true if either all elements of the stream match the provided predicate or the stream is empty, otherwise false.

Note : If the stream is empty then true is returned and the predicate is not evaluated.

Example 1 : allMatch() function to check whether all elements are divisible by 3.

// Java code for DoubleStream allMatch
// (DoublePredicate predicate) to check whether
// all elements of this stream match
// the provided predicate.
import java.util.*;
import java.util.stream.DoubleStream;

class GFG {

    // Driver code
    public static void main(String[] args)
    {
        // Creating an DoubleStream
        DoubleStream stream = DoubleStream.of(3.8, 5.6, 9.2,
                                              12.5, 14.7);

        // Check if all elements of stream
        // are divisible by 3 or not using
        // DoubleStream allMatch(DoublePredicate predicate)
        boolean answer = stream.allMatch(num -> num % 3 == 0);

        // Displaying the result
        System.out.println(answer);
    }
}

Output:

false

Example 2 : allMatch() function to check whether all elements in the DoubleStream obtained after concatenating two DoubleStreams are less than 2.

// Java code for DoubleStream allMatch
// (DoublePredicate predicate) to check whether
// all elements of this stream match
// the provided predicate.
import java.util.*;
import java.util.stream.DoubleStream;

class GFG {

    // Driver code
    public static void main(String[] args)
    {
        // Creating an DoubleStream after concatenating
        // two DoubleStreams
        DoubleStream stream = DoubleStream.concat(
            DoubleStream.of(-2.2, -4.3, -6.4, -8.5),
            DoubleStream.of(-1.5, 0, 1.7, 5.9));

        // Check if all elements of stream
        // are less than 2 or not using
        // DoubleStream allMatch(DoublePredicate predicate)
        boolean answer = stream.allMatch(num -> num < 2.0);

        // Displaying the result
        System.out.println(answer);
    }
}

Output:

false

Example 3 : allMatch() function to show if the stream is empty then true is returned.

// Java code for DoubleStream allMatch
// (DoublePredicate predicate) to check whether
// any element of this stream match
// the provided predicate.
import java.util.*;
import java.util.stream.DoubleStream;

class GFG {

    // Driver code
    public static void main(String[] args)
    {
        // Creating an empty DoubleStream
        DoubleStream stream = DoubleStream.empty();

        boolean answer = stream.allMatch(num -> true);

        // Displaying the result
        System.out.println(answer);
    }
}

Output:

true