What is Collection API?

Difference between array and vector

1. The size of array is static, while a vector is a dynamically resizable.
2. Vector can store only object reference not any primitive data type. Unlike arrays, vector can contain any combination of object data type.
3. Array is accessed directly through its integer index. The method elementAt(index)  of vector is used to retrieve a given reference at specified index.

/* example of vector class */
import java.util.*;
class VectorClass
{
	public static void main(String arg[])
	{
		Vector V=new Vector();
		V.addElement(new Integer(10));
		V.addElement(new Integer(20));
		V.addElement(new Integer(30));
		System.out.println(V);
		V.addElement(new Double(55.45);
		System.out.println(V);
		V.removeElement(new Integer(30));
		System.out.println(V);
			if(V.contains(new Integer(20)))
		System.out.println("20 is present " +V.indexOf(new Integer(20)));
			else
		System.out.println("20 is not present");
	}
}

Introduction to ArrayList

It is similar to vector, a dynamic resizable array. Both classes inheritance from AbstractList, and implement the interface list.
Array List is compared with vector both are dynamically resizable, both have some common method but it does not have legacy method that Vector has, like elementAt( ), addElement( ).

// example of ArrayList
import java.util.*;
class Alist
{
	public static void main(String arg[])
	{
		ArrayList a=new ArrayList(2);
		a.add(new Integer(10));
		a.add(new Integer(20));
		a.add(new Float(30.4));
		a.add(new Integer(45));
		System.out.println("contents of a:"+a);
		a.add(2,new Integer(5)); // it is insert into the 2nd position
		System.out.println("contents of a:"+a);
		a.remove(2);
		System.out.println("contents of a:"+a);
	}
}

Guide to LinkedList

It adds new functionality that vector did not have previously. It has method like addList( ), addlast( ) to add elements to start or end of the list. It has method like getList( ), getLast( ), removeFirst( ), removeLast( ). So, using the Link list we can handle more perfectly the data elements.

// Demonstrate LinkedList.
import java.util.*;
class LinkedListDemo
{
	public static void main(String args[])
	{
		// create a linked list
		LinkedList ll = new LinkedList();
		// add elements to the linked list
		ll.add("F");
		ll.add("B");
		ll.add("D");
		ll.add("E");
		ll.add("C");
		ll.addLast("Z");
		ll.addFirst("A");
		ll.add(1, "A2");
		System.out.println("Original contents of ll: " + ll);
		// remove elements from the linked list
		ll.remove("F");
		ll.remove(2);
		System.out.println("Contents of ll after deletion: " + ll);
		// remove first and last elements
		ll.removeFirst();
		ll.removeLast();
		System.out.println("ll after deleting first and last: " + ll);
		// get and set a value
		Object val = ll.get(2);
		ll.set(2, (String) val + " Changed");
		System.out.println("ll after change: " + ll);
	}
}

Hash Table

A hash table is not as array or vector.It allows developer a more specific means of accessing data other than index value. Keys and value can be made up or any non-null object. This class extends from the class dictionary and implements the interfaces. The creation of use of Hash Table is similar to Vector, instantiation of its result in an empty Hash Table, where elements are add using put with key and value arguments of type object. To retrieve object from a Hash Table, the object used as keys must implements method hashCode( ) and equals( ).

//Testting Hashtable behavior when objects representating the same
//entity are used as hastable keys
class Program
{
	static void Main(string[] args)
		{
			Hashtable col = new Hashtable();
			col["key1"] = "Value1";
			col["key2"] = "Value2";
			DisplayResults(col);
			col["key2"] = "Value2Updated";
			DisplayResults(col);
			System.Console.Read();
		}
	static void DisplayResults (Hashtable col)
		{
			Console.WriteLine();
			Console.WriteLine("Total Items: {0}",col.Count);
			foreach (DictionaryEntry entry in col)
				{
					Console.WriteLine(
						"Key[{0}], Hash[{1}], Value[{2}]",
						entry.Key,
						entry.Key.GetHashCode().ToString(),
						entry.Value);
				}
		}
}

Conclusion

Use right typeface for your documents

When you make conversation with somebody, your body languages, and words plays a big role in your mood and makes the conversation richer. Like that the typeface you used in your document irrespective in printing media or online publishing, construct the mood of reader. So when you are writing your next document doesn’t ignore this stuff. Only choosing the right font is not the only way to construct the mood of reader. Size, color, underline, style have a strong impact on reader. Now go through this article to know how to use the right typography for your document.

Understanding the difference: Typeface and Fonts

I have experienced that most of the people take this two term typeface and typography as same. But technically they don’t carry the same meaning. Font is just a font-family of a character. i.e. Verdana or Arial is determined as typography whereas typeface is the font-family is the details about font-family. i.e.  “Verdana, Italic, 15pt” is constitute as font-face. So a font face describes the state of your font. Most of the people choose the font from two major font-families namely Serif, Sans-serif. You can use Decorative font in your design.

Understanding the difference: Serif & Sans-Serif fonts

Serif fonts have a short stroke at the start and end of every letter. These strokes are called serif. Serif fonts are broadly used in legal documents, letter, newsletter and all other printing documents as it has the better readability.

‘Sans’ is a French word that means ’without’. That means sans-serif font don’t have the decorative strokes at the start and end of a letter. This font-family has a very smooth and eye catching font that mostly used in web (online) publishing and in the header of an article.

Serif fonts have a short decorative strokes at the begining and end of every letter

Decorative strokes are missing in Sans-Serif fonts

Some Popular fonts of Serif families listed below:

• Book Antiqua: Popularly used in the body text of multi-page report as it has a very great readability even in small font size.
• Courier New: This font falls under moonscape font-family. It’s widely used in technological writing, scripting, examples and illustrations.
• Garamond: This font is mostly used in email communication, notice and circulars.
• Times: Times and Times New Roman has a little kerning difference. The character come closer in the Times font.
• Times New Roman: This was the default font for the old Microsoft products. Since the printing media has offered a higher resolution print, this font doesn’t appear hazy or blur.

Some Popular of Sans-serif families listed below:

• Arial: It’s the most classic Sans-serif font. Used in most of web design and this is the default font for most of the browsers.
• Arial Black: You can say it’s the bolder version of Arial font. It’s mostly used in web heading but not in body text.
• Calibri: This is the default font for Windows 7, Windows Vista, Office 2007 and 2010. This is a very smooth font can be read online. But it need some negative kerning for better readability.
• Helvetica: Very Clear, Ideal for numbers. It’s an alternative to Arial.
• Microsoft Sans Serif: Excellent for body text of a web page.
• Verdana: Mostly Used in email communication. It’s a great font that can be used anywhere irrespective body or heading text of a web page.

Font Viewer:

fontviewer screenshot

To choose the right font you need to type some text and check that with every font available in your system. But this process is very a time wasting. But you can do the same thing with font viewing software. Font viewing software makes it easy to choose the right font for your occasion. Now we are taking a look on the FONT VIEWER software. You can download this software from http://www.fontviewer.net . And in the ‘text to display box’ type the text that you want to check with every available font. Change the foreground, background color and the size to exactly see how the text will look in your document. Click on the go button and you will see the text is displaying in a table with every available font in your system with Bold, Italic, Bold & Italic view.

Tips for using the right font:

• Don’t use more than three fonts in your document.
• Don’t use larger than 18pt size in heading.
• Use smaller than 12pt size for body text.
• Use Sans-Serif fonts for body text and Serif fonts for Heading.
• Try To use contrast color in heading to attract reader.
• Use Italic style for some word that shouldn’t be overlooked, Use Bold for mediocre important words and use bold and words for high sensitive words in your document.
• Adjust the kerning option for better readability.