bennadel/code-1.htm

## code-1.htm
<!DOCTYPE html>
<html>
<head>
	<title>Fixed-Length Queue Data Type In JavaScript</title>

	<script type="text/javascript">


		// Create a constructor for the fixed-length queue. This is
		// really more of a FACTORY than a construtor since an
		// entirely tangential object is returned.
		function FixedQueue( size, initialValues ){

			// If there are no initial arguments, default it to
			// an empty value so we can call the constructor in
			// a uniform way.
			initialValues = (initialValues || []);

			// Create the fixed queue array value.
			var queue = Array.apply( null, initialValues );

			// Store the fixed size in the queue.
			queue.fixedSize = size;

			// Add the class methods to the queue. Some of these have
			// to override the native Array methods in order to make
			// sure the queue lenght is maintained.
			queue.push = FixedQueue.push;
			queue.splice = FixedQueue.splice;
			queue.unshift = FixedQueue.unshift;

			// Trim any initial excess from the queue.
			FixedQueue.trimTail.call( queue );

			// Return the new queue.
			return( queue );

		}


		// I trim the queue down to the appropriate size, removing
		// items from the beginning of the internal array.
		FixedQueue.trimHead = function(){

			// Check to see if any trimming needs to be performed.
			if (this.length <= this.fixedSize){

				// No trimming, return out.
				return;

			}

			// Trim whatever is beyond the fixed size.
			Array.prototype.splice.call(
				this,
				0,
				(this.length - this.fixedSize)
			);

		};


		// I trim the queue down to the appropriate size, removing
		// items from the end of the internal array.
		FixedQueue.trimTail = function(){

			// Check to see if any trimming needs to be performed.
			if (this.length <= this.fixedSize){

				// No trimming, return out.
				return;

			}

			// Trim whatever is beyond the fixed size.
			Array.prototype.splice.call(
				this,
				this.fixedSize,
				(this.length - this.fixedSize)
			);

		};


		// I synthesize wrapper methods that call the native Array
		// methods followed by a trimming method.
		FixedQueue.wrapMethod = function( methodName, trimMethod ){

			// Create a wrapper that calls the given method.
			var wrapper = function(){

				// Get the native Array method.
				var method = Array.prototype[ methodName ];

				// Call the native method first.
				var result = method.apply( this, arguments );

				// Trim the queue now that it's been augmented.
				trimMethod.call( this );

				// Return the original value.
				return( result );

			};

			// Return the wrapper method.
			return( wrapper );

		};


		// Wrap the native methods.
		FixedQueue.push = FixedQueue.wrapMethod(
			"push",
			FixedQueue.trimHead
		);

		FixedQueue.splice = FixedQueue.wrapMethod(
			"splice",
			FixedQueue.trimTail
		);

		FixedQueue.unshift = FixedQueue.wrapMethod(
			"unshift",
			FixedQueue.trimTail
		);


		// -------------------------------------------------- //
		// -------------------------------------------------- //
		// -------------------------------------------------- //
		// -------------------------------------------------- //


		// Create a fixed queue with some values.
		var friends = FixedQueue( 3, [ "Sarah", "Kit" ] );

		console.log( "Initial Values" );
		console.log( friends );

		// Add 2 items to the head.
		friends.unshift( "Tricia", "Anna" );

		console.log( "Add [ Tricia, Anna ] to head." );
		console.log( friends );

		// Add 2 items to the tail.
		friends.push( "Kim", "Joanna" );

		console.log( "Add [ Kim, Joanna ] to tail." );
		console.log( friends );

		// Add explicit value outside array.
		friends[ 5 ] = "Nancy";

		console.log( "Add [ Nancy ] out of bounds (explicitly)." );
		console.log( friends );

		// Add another item to the tail.
		friends.push( "Becca" );

		console.log( "Add [ Becca ] to tail." );
		console.log( friends );


	</script>

</head>
<body>
	<!-- Left intentionally blank. -->
</body>
</html>
	<!DOCTYPE html>
	<html>
	<head>
	<title>Fixed-Length Queue Data Type In JavaScript</title>

	<script type="text/javascript">


	// Create a constructor for the fixed-length queue. This is
	// really more of a FACTORY than a construtor since an
	// entirely tangential object is returned.
	function FixedQueue( size, initialValues ){

	// If there are no initial arguments, default it to
	// an empty value so we can call the constructor in
	// a uniform way.
	initialValues = (initialValues \|\| []);

	// Create the fixed queue array value.
	var queue = Array.apply( null, initialValues );

	// Store the fixed size in the queue.
	queue.fixedSize = size;

	// Add the class methods to the queue. Some of these have
	// to override the native Array methods in order to make
	// sure the queue lenght is maintained.
	queue.push = FixedQueue.push;
	queue.splice = FixedQueue.splice;
	queue.unshift = FixedQueue.unshift;

	// Trim any initial excess from the queue.
	FixedQueue.trimTail.call( queue );

	// Return the new queue.
	return( queue );

	}


	// I trim the queue down to the appropriate size, removing
	// items from the beginning of the internal array.
	FixedQueue.trimHead = function(){

	// Check to see if any trimming needs to be performed.
	if (this.length <= this.fixedSize){

	// No trimming, return out.
	return;

	}

	// Trim whatever is beyond the fixed size.
	Array.prototype.splice.call(
	this,
	0,
	(this.length - this.fixedSize)
	);

	};


	// I trim the queue down to the appropriate size, removing
	// items from the end of the internal array.
	FixedQueue.trimTail = function(){

	// Check to see if any trimming needs to be performed.
	if (this.length <= this.fixedSize){

	// No trimming, return out.
	return;

	}

	// Trim whatever is beyond the fixed size.
	Array.prototype.splice.call(
	this,
	this.fixedSize,
	(this.length - this.fixedSize)
	);

	};


	// I synthesize wrapper methods that call the native Array
	// methods followed by a trimming method.
	FixedQueue.wrapMethod = function( methodName, trimMethod ){

	// Create a wrapper that calls the given method.
	var wrapper = function(){

	// Get the native Array method.
	var method = Array.prototype[ methodName ];

	// Call the native method first.
	var result = method.apply( this, arguments );

	// Trim the queue now that it's been augmented.
	trimMethod.call( this );

	// Return the original value.
	return( result );

	};

	// Return the wrapper method.
	return( wrapper );

	};


	// Wrap the native methods.
	FixedQueue.push = FixedQueue.wrapMethod(
	"push",
	FixedQueue.trimHead
	);

	FixedQueue.splice = FixedQueue.wrapMethod(
	"splice",
	FixedQueue.trimTail
	);

	FixedQueue.unshift = FixedQueue.wrapMethod(
	"unshift",
	FixedQueue.trimTail
	);



	// -------------------------------------------------- //
	// -------------------------------------------------- //
	// -------------------------------------------------- //
	// -------------------------------------------------- //



	// Create a fixed queue with some values.
	var friends = FixedQueue( 3, [ "Sarah", "Kit" ] );

	console.log( "Initial Values" );
	console.log( friends );

	// Add 2 items to the head.
	friends.unshift( "Tricia", "Anna" );

	console.log( "Add [ Tricia, Anna ] to head." );
	console.log( friends );

	// Add 2 items to the tail.
	friends.push( "Kim", "Joanna" );

	console.log( "Add [ Kim, Joanna ] to tail." );
	console.log( friends );

	// Add explicit value outside array.
	friends[ 5 ] = "Nancy";

	console.log( "Add [ Nancy ] out of bounds (explicitly)." );
	console.log( friends );

	// Add another item to the tail.
	friends.push( "Becca" );

	console.log( "Add [ Becca ] to tail." );
	console.log( friends );


	</script>

	</head>
	<body>
	<!-- Left intentionally blank. -->
	</body>
	</html>