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Pattern asPredicate() method in Java with examples
The Predicate interface of the java.util.function package can be used as a target for lambda expressions. The test method of this interface accepts a value ad validates it with the current value of the Predicate object. This method returns true in-case of a match, else false.
The asPredicate() method of the java.util.regex.Pattern class returns a Predicate object which can match a string with the regular expression using which the current Pattern object was compiled.
Example 1
import java.util.Scanner;
import java.util.function.Predicate;
import java.util.regex.Pattern;
public class AsPredicateExample {
public static void main( String args[] ) {
//Reading string value
Scanner sc = new Scanner(System.in);
System.out.println("Enter input string");
String input = sc.nextLine();
//Regular expression to find digits
String regex = "[t]";
//Compiling the regular expression
Pattern pattern = Pattern.compile(regex, Pattern.CASE_INSENSITIVE);
//Converting the regular expression to predicate
Predicate<String> predicate = pattern.asPredicate();
//Testing the predicate with the input string
boolean result = predicate.test(input);
if(result) {
System.out.println("Match found");
} else {
System.out.print("Match not found");
}
}
}Output
Enter input string Tutorialspoint Number of matches: 3
Example 2
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Scanner;
import java.util.function.Predicate;
import java.util.regex.Pattern;
public class AsPredicateExample {
public static void main( String args[] ) {
ArrayList<String> list = new ArrayList<String>();
list.addAll(Arrays.asList("Java", "JavaFX", "Hbase", "JavaScript"));
//Regular expression to find digits
String regex = "[J]";
//Compiling the regular expression
Pattern pattern = Pattern.compile(regex);
//Converting the regular expression to predicate
Predicate<String> predicate = pattern.asPredicate();
list.forEach(n -> { if (predicate.test(n)) System.out.println("Match found "+n); });
}
}Output
Match found Java Match found JavaFX Match found JavaScript
Updated on: 20-Nov-2019
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