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CharMatcher Class in Java
The CharMatcher class determines a true or false value for any Java char value, just as Predicate does for any Object.
| Sr.No | Methods & Description |
|---|---|
| 1 | CharMatcher and(CharMatcher other)Returns a matcher that matches any character matched by both this matcher and other. |
| 2 | static CharMatcher anyOf(CharSequence sequence)Returns a char matcher that matches any character present in the given character sequence. |
| 3 | boolean apply(Character character)Deprecated. Provided only to satisfy the Predicate interface; use matches(char) instead. |
| 4 | String collapseFrom(CharSequence sequence, char replacement)Returns a string copy of the input character sequence, with each group of consecutive characters that match this matcher replaced by a single replacement character. |
| 5 | int countIn(CharSequence sequence)Returns the number of matching characters found in a character sequence. |
| 6 | static CharMatcher forPredicate(Predicate<? super Character> predicate)Returns a matcher with identical behavior to the given Character-based predicate, but which operates on primitive char instances instead. |
| 7 | int indexIn(CharSequence sequence)Returns the index of the first matching character in a character sequence, or -1 if no matching character is present. |
Create the following java program using any editor of your choice in say C:/> Guava.
Example
Following is the GuavaTester.java code −
import com.google.common.base.CharMatcher;
import com.google.common.base.Splitter;
public class GuavaTester {
public static void main(String args[]) {
GuavaTester tester = new GuavaTester();
tester.testCharMatcher();
}
private void testCharMatcher() {
System.out.println(CharMatcher.DIGIT.retainFrom("mahesh123")); // only the digits
System.out.println(CharMatcher.WHITESPACE.trimAndCollapseFrom(" Mahesh Parashar ", ' '));
// trim whitespace at ends, and replace/collapse whitespace into single spaces
System.out.println(CharMatcher.JAVA_DIGIT.replaceFrom("mahesh123", "*"));
// star out all digits
System.out.println(CharMatcher.JAVA_DIGIT.or(CharMatcher.JAVA_LOWER_CASE).retainFrom("mahesh123"));
// eliminate all characters that aren't digits or lowercase
}
}
Compile the class using javac compiler as follows
C:\Guava>javac GuavaTester.java
Now run the GuavaTester to see the result −
C:\Guava>java GuavaTester
Output
This will produce the following output −
123 Mahesh Parashar mahesh*** mahesh123
Updated on: 20-Feb-2020
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