Java Tutorial/Apache Common/ObjectUtils
Содержание
ObjectUtils.defaultIfNull
<source lang="java">
import org.apache.rumons.lang.ObjectUtils; public class MainClass {
public static void main(String[] args) { //Create ObjectUtilsTrial instance MyClass one = new MyClass(); MyClass two = one; //Same Reference MyClass three = new MyClass(); //New Object MyClass four = null; //four is null, returns DEFAULT System.out.print("1) If null return DEFAULT >>>"); System.out.println(ObjectUtils.defaultIfNull(four, "DEFAULT")); }
} class MyClass{
public String toString() { return "toString Output"; }
}</source>
1) If null return DEFAULT >>>DEFAULT
ObjectUtils.equals
<source lang="java">
import org.apache.rumons.lang.ObjectUtils; public class MainClass {
public static void main(String[] args) { //Create ObjectUtilsTrial instance MyClass one = new MyClass(); MyClass two = one; //Same Reference MyClass three = new MyClass(); //New Object MyClass four = null;
//one and two point to the same object System.out.print("2) References to the same object >>>"); System.out.println(ObjectUtils.equals(one, two)); }
} class MyClass{
public String toString() { return "toString Output"; }
}</source>
2) References to the same object >>>true
ObjectUtils.equals2
<source lang="java">
import org.apache.rumons.lang.ObjectUtils; public class MainClass {
public static void main(String[] args) { //Create ObjectUtilsTrial instance MyClass one = new MyClass(); MyClass two = one; //Same Reference MyClass three = new MyClass(); //New Object MyClass four = null; //one and three are different objects System.out.print("3) Check object references and not values >>>"); System.out.println(ObjectUtils.equals(one, three)); }
} class MyClass{
public String toString() { return "toString Output"; }
}</source>
3) Check object references and not values >>>false
ObjectUtils.identityToString
<source lang="java">
import org.apache.rumons.lang.ObjectUtils; public class MainClass {
public static void main(String[] args) { //Create ObjectUtilsTrial instance MyClass one = new MyClass(); MyClass two = one; //Same Reference MyClass three = new MyClass(); //New Object MyClass four = null; //Object details displayed..toString is not called System.out.print("5) Display object details >>>"); System.out.println(ObjectUtils.identityToString(one)); }
} class MyClass{
public String toString() { return "toString Output"; }
}</source>
5) Display object details >>>MyClass@b89838
ObjectUtils.toString
<source lang="java">
import org.apache.rumons.lang.ObjectUtils; public class MainClass {
public static void main(String[] args) { //Create ObjectUtilsTrial instance MyClass one = new MyClass(); MyClass two = one; //Same Reference MyClass three = new MyClass(); //New Object MyClass four = null; //Pass null get empty string System.out.print("6) Pass null and get back an Empty string >>>"); System.out.println("**" + ObjectUtils.toString(null) + "**"); }
} class MyClass{
public String toString() { return "toString Output"; }
}</source>
6) Pass null and get back an Empty string >>>****