Friday 11 November 2022

How to check the object is an iterable or not?

Using Class.isAssignableFrom method, we can check whether given object is an iterable or not.

 

Signature

public native boolean isAssignableFrom(Class<?> cls)

'isAssignableFrom' method return true, if the class or interface represented by this Class object is either the same as, or is a superclass or superinterface of, the class or interface represented by the specified Class parameter, else false.

 

Example

public static boolean isIterable(final Class<?> clazz) {
    return clazz != null && (Iterable.class.isAssignableFrom(clazz));
}

 

Above snippet return true, if the given type an iterable, else false.

 


Find the below working application.

 

IterableCheckDemo.java
package com.sample.app.collections;

import java.util.Arrays;
import java.util.HashMap;

public class IterableCheckDemo {
	
	public static boolean isIterable(final Class<?> clazz) {
        return clazz != null && (Iterable.class.isAssignableFrom(clazz));
    }
	
	public static void main(String[] args) {
		final Object list = Arrays.asList(2, 3, 5, 7);
		final Object map = new HashMap<>();
		
		System.out.println("Is list iterable : " + isIterable(list.getClass()));
		System.out.println("Is map iterable : " + isIterable(map.getClass()));
	}

}

 

Output

Is list iterable ? true
Is map iterable ? false

 

  

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