What is the ComparableUtils.lt method in Java?

Overview

The lt() method is a staticA static method in Java is one that can be called without creating an object of the specified class. method of the ComparableUtils class that returns a predicate for the passed value. The predicate checks for the lesser than condition against the passed value.

Note: Refer to the What is a Java predicate? shot to learn more about predicates in Java.

How to import ComparableUtils

The definition of ComparableUtils can be found in the Apache Commons Lang package, which we can add to the Maven project by adding the following dependency to the pom.xml file:

<dependency>
            <groupId>org.apache.commons</groupId>
            <artifactId>commons-lang3</artifactId>
            <version>3.12.0</version>
</dependency>

Note: For other versions of the commons-lang package, we can refer to the Maven Repository.

We can import the ComparableUtils class like this:

import org.apache.commons.lang3.compare.ComparableUtils;

Syntax

public static <A extends Comparable<A>> Predicate<A> lt(final A b)

Parameter value

  • final A b: This is the object that needs to be compared to in the returned predicate.

Return value

This method returns a predicate.

Code

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>org.example</groupId>
    <artifactId>test</artifactId>
    <version>1.0-SNAPSHOT</version>

    <properties>
        <maven.compiler.source>8</maven.compiler.source>
        <maven.compiler.target>8</maven.compiler.target>
    </properties>

    <dependencies>

        <dependency>
            <groupId>org.apache.commons</groupId>
            <artifactId>commons-lang3</artifactId>
            <version>3.12.0</version>
        </dependency>

    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-shade-plugin</artifactId>
                <version>2.1</version>
                <executions>
                    <execution>
                        <phase>package</phase>
                        <goals>
                            <goal>shade</goal>
                        </goals>
                        <configuration>
                            <transformers>
                                <transformer
                                        implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
                                    <mainClass>Main</mainClass>
                                </transformer>
                            </transformers>
                        </configuration>
                    </execution>
                </executions>
            </plugin>
        </plugins>
    </build>

</project>
Implementing the ComparableUtils method

Explanation

The Maven dependency for the ComparableUtils method is present in the pom.xml file:

Main.java

  • Lines 1–2: We import the relevant classes.
  • Line 7: We define an integer variable called val.
  • Line 8: We pass val as a parameter to the ComparableUtils.lt() method. This returns a predicate called lesserThan.
  • Line 9: We define an integer test value called testVal.
  • Line 10: We use the test() method of the predicate to test whether or not the testVal value is lesser than the val value. Then, we print the result of the comparison.
  • Line 11: We assign a new test value to testVal.
  • Line 12: We use the test() method of the predicate to test whether or not the testVal value is lesser than the val value. Then, we print the result of the comparison.

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