asked on

array example

Hi,

i was trying below example
http://www.avajava.com/tutorials/lessons/whats-a-quick-way-to-output-the-values-in-an-array.html?page=1

import org.apache.commons.lang.ArrayUtils;
import org.apache.commons.lang.builder.ToStringBuilder;

public class ArrayTest {

	private class TestClass {
		private String val1;
		private String val2;

		public TestClass(String v1, String v2) {
			val1 = v1;
			val2 = v2;
		}

		public String getVal1() {
			return val1;
		}

		public String getVal2() {
			return val2;
		}

		public String toString() {
			return "\n" + ToStringBuilder.reflectionToString(this);
		}
	}

	public static void main(String[] args) {
		int[] intArray = { 1, 2, 3, 4, 3, 2, 1 };
		System.out.println("intArray: " + intArray);
		System.out.println("intArray values: " + ArrayUtils.toString(intArray));

		String[] stringArray = { "Hello", "Goodbye", "Later" };
		System.out.println("\nstringArray: " + stringArray);
		System.out.println("stringArray values: " + ArrayUtils.toString(stringArray));

		ArrayTest at = new ArrayTest();
		TestClass tc1 = at.new TestClass("my value 1", "my value 2");
		TestClass tc2 = at.new TestClass("another value 1", "another value 2");
		TestClass[] testClassArray = { tc1, tc2 };
		System.out.println("\ntestClassArray: " + testClassArray);
		System.out.println("testClassArray values: " + ArrayUtils.toString(testClassArray));
	}
}

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i have not understod what author is trying to mention in this example.

what is happening in below 3 lines

TestClass tc1 = at.new TestClass("my value 1", "my value 2");
TestClass tc2 = at.new TestClass("another value 1", "another value 2");
TestClass[] testClassArray = { tc1, tc2 };

please advise
Any links resources ideas highly appreciated. Thanks in advance

SOLUTION

CPColin

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krakatoa

The example seems to just boil down to an illustration of the reflective use of

ToStringBuilder.reflectionToString(this);

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which is essentially a way for the interpreter to get hold of the values (fields) in an object at runtime, so instead of iterating through the fields explicitly, this function does that bit for you.

The three lines you mention instantiate an inner class, and set its fields.

gudii9

ASKER

public String toString() {
return "\n" + ToStringBuilder.reflectionToString(this);
}

what is happening in above lines.

Also

TestClass tc1 = at.new TestClass("my value 1", "my value 2");
            TestClass tc2 = at.new TestClass("another value 1", "another value 2");
            TestClass[] testClassArray = { tc1, tc2 };
            System.out.println("\ntestClassArray: " + testClassArray);
            System.out.println("testClassArray values: " + ArrayUtils.toString(testClassArray));

After initializing and setting inner class why the output is coming as
ArrayTest$TestClass@4318f375[val1=my value 1,val2=my value 2],
ArrayTest$TestClass@36867e89[val1=another value 1,val2=another value 2]}

also

TestClass[] testClassArray = { tc1, tc2 };

what is happening in above line. Sending both inner classes into an array?
How is TestClass[](array) different from TestClass(.java class). Where we defined TestClass[] array.
Please advise

SOLUTION

krakatoa

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ASKER CERTIFIED SOLUTION

Mahesh Bhutkar

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