Add Proxy Design Patterns

Author: tcorral

Proxy/1/PublicLibrary.js

@@ -0,0 +1,64 @@
+var PublicLibrary = function(books)
+{
+	// implements Library
+	this.catalog =
+	{
+	};
+	for(var i = 0, len = books.length; i < len; i++)
+	{
+		this.catalog[books[i].getIsbn()] =
+		{
+			book : books[i],
+			available : true
+		};
+	}
+};
+PublicLibrary.prototype =
+{
+	findBooks : function(searchString)
+	{
+		var results = [];
+		for(var isbn in this.catalog)
+		{
+			if(!this.catalog.hasOwnProperty(isbn))
+				continue;
+			if(searchString.match(this.catalog[isbn].getTitle()) || searchString.match(this.catalog[isbn].getAuthor()))
+			{
+				results.push(this.catalog[isbn]);
+			}
+		}
+		return results;
+	},
+	checkoutBook : function(book)
+	{
+		var isbn = book.getIsbn();
+		if(this.catalog[isbn])
+		{
+			if(this.catalog[isbn].available)
+			{
+				this.catalog[isbn].available = false;
+				return this.catalog[isbn];
+			}
+			else
+			{
+				throw new Error('PublicLibrary: book ' + book.getTitle() + ' is not currently available.');
+			}
+		}
+		else
+		{
+			throw new Error('PublicLibrary: book ' + book.getTitle() + ' not found.');
+		}
+	},
+	returnBook : function(book)
+	{
+		var isbn = book.getIsbn();
+		if(this.catalog[isbn])
+		{
+			this.catalog[isbn].available = true;
+		}
+		else
+		{
+			throw new Error('PublicLibrary: book ' + book.getTitle() + ' not found.');
+		}
+	}
+};

Proxy/1/PublicLibraryProxy.js

@@ -0,0 +1,20 @@
+var PublicLibraryProxy = function(catalog)
+{
+	// implements Library
+	this.library = new PublicLibrary(catalog);
+};
+PublicLibraryProxy.prototype =
+{
+	findBooks : function(searchString)
+	{
+		return this.library.findBooks(searchString);
+	},
+	checkoutBook : function(book)
+	{
+		return this.library.checkoutBook(book);
+	},
+	returnBook : function(book)
+	{
+		return this.library.returnBook(book);
+	}
+};

Proxy/Virtual/PublicLibrary.js

@@ -0,0 +1,64 @@
+var PublicLibrary = function(books)
+{
+	// implements Library
+	this.catalog =
+	{
+	};
+	for(var i = 0, len = books.length; i < len; i++)
+	{
+		this.catalog[books[i].getIsbn()] =
+		{
+			book : books[i],
+			available : true
+		};
+	}
+};
+PublicLibrary.prototype =
+{
+	findBooks : function(searchString)
+	{
+		var results = [];
+		for(var isbn in this.catalog)
+		{
+			if(!this.catalog.hasOwnProperty(isbn))
+				continue;
+			if(searchString.match(this.catalog[isbn].getTitle()) || searchString.match(this.catalog[isbn].getAuthor()))
+			{
+				results.push(this.catalog[isbn]);
+			}
+		}
+		return results;
+	},
+	checkoutBook : function(book)
+	{
+		var isbn = book.getIsbn();
+		if(this.catalog[isbn])
+		{
+			if(this.catalog[isbn].available)
+			{
+				this.catalog[isbn].available = false;
+				return this.catalog[isbn];
+			}
+			else
+			{
+				throw new Error('PublicLibrary: book ' + book.getTitle() + ' is not currently available.');
+			}
+		}
+		else
+		{
+			throw new Error('PublicLibrary: book ' + book.getTitle() + ' not found.');
+		}
+	},
+	returnBook : function(book)
+	{
+		var isbn = book.getIsbn();
+		if(this.catalog[isbn])
+		{
+			this.catalog[isbn].available = true;
+		}
+		else
+		{
+			throw new Error('PublicLibrary: book ' + book.getTitle() + ' not found.');
+		}
+	}
+};

Proxy/Virtual/PublicLibraryVirtualProxy.js

@@ -0,0 +1,32 @@
+var PublicLibraryVirtualProxy = function(catalog)
+{
+	// implements Library
+	this.library = null;
+	this.catalog = catalog;
+	// Store the argument to the constructor.
+};
+PublicLibraryVirtualProxy.prototype =
+{
+	_initializeLibrary : function()
+	{
+		if(this.library === null)
+		{
+			this.library = new PublicLibrary(this.catalog);
+		}
+	},
+	findBooks : function(searchString)
+	{
+		this._initializeLibrary();
+		return this.library.findBooks(searchString);
+	},
+	checkoutBook : function(book)
+	{
+		this._initializeLibrary();
+		return this.library.checkoutBook(book);
+	},
+	returnBook : function(book)
+	{
+		this._initializeLibrary();
+		return this.library.returnBook(book);
+	}
+};