Creating Typed Java Arrays In ColdFusion Using JavaCast()

java-cast-arrays.cfm

<cfscript>

	// Byte arrays. Binary data is represented by an array of bytes.
	// And, each byte is represented by an integer. For simple values,
	// we don't have to manually cast each value - we can just pass-in
	// the array and ColdFusion will perform the cast.

	// Test 1 - Spell "SARAH" with ColdFusion numbers.

	bytes = javaCast(
		"byte[]",
		[ 83, 65, 82, 65, 72 ]
	);

	writeOutput( charsetEncode( bytes, "utf-8" ) & "<br />" );

	// Test 2 - Spell "SARAH" with Java bytes.

	bytes = javaCast(
		"byte[]",
		[
			javaCast( "byte", 83 ),
			javaCast( "byte", 65 ),
			javaCast( "byte", 82 ),
			javaCast( "byte", 65 ),
			javaCast( "byte", 72 )
		]
	);

	writeOutput( charsetEncode( bytes, "utf-8" ) & "<br />" );


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


	// Char arrays. Character arrays work the same way that byte
	// arrays work: you don't have to perform the cast manually
	// for each character - ColdFusion will do that for you. To
	// test this, we'll use a StringBuffer which can accept char[]
	// as an append() argument.

	buffer = createObject( "java", "java.lang.StringBuffer" ).init();

	// Test 1 - Add "TRICIA" with ColdFusion strings.

	buffer.append(
		javaCast( "char[]", [ "T", "R", "I", "C", "I", "A" ] )
	);

	// Test 2 - Add "TRICIA" with Java chars.

	buffer.append(
		javaCast(
			"char[]",
			[
				javaCast( "char", "T" ),
				javaCast( "char", "R" ),
				javaCast( "char", "I" ),
				javaCast( "char", "C" ),
				javaCast( "char", "I" ),
				javaCast( "char", "A" )
			]
		)
	);

	// Since we appended twice, should output "TRICIATRICIA".
	writeOutput( buffer.toString() & "<br />" );


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


	// String arrays. Although a slightly more complex data type,
	// strings work the same way that bytes and chars work. You don't
	// have to cast the individual values manually. To test this, we'll
	// use the common string utils which can accepts String[] as an
	// argument in some methods.

	utils = createObject( "java", "org.apache.commons.lang.StringUtils" );

	// Test 1 - Use ColdFusion strings.

	inputs = javaCast(
		"string[]",
		[
			"Hello world",
			"Hello there!",
			"Hell yis!"
		]
	);

	writeOutput( utils.getCommonPrefix( inputs ) & "<br />" );

	// Test 2 - Use Java strings (which are really the same thing).

	inputs = javaCast(
		"string[]",
		[
			javaCast( "string", "Hello world" ),
			javaCast( "string", "Hello cutie pie!" ),
			javaCast( "string", "Hell yis!" )
		]
	);

	writeOutput( utils.getCommonPrefix( inputs ) & "<br />" );


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


	// With simple values like integer, char, string, float, long,
	// etc., ColdFusion will create a types array and ensure that
	// each item within that array is properly casted. With complex
	// Java Class instances, things are a little less flexible. If
	// you need a typed array of some set of class instances, you
	// have to make sure that each item is *alread* in the proper
	// data type.

	// In ColdFusion, a common example of this is the need to create
	// a collection of URL[] instances for a Java class loader. First,
	// we have to create a ColdFusion array that is populated with
	// actual Java URL instances:
	urls = [
		createObject( "java", "java.net.URL" ).init(
			javaCast( "string", "file:///foo" )
		),
		createObject( "java", "java.net.URL" ).init(
			javaCast( "string", "file:///bar" )
		)
	];

	// Once we have the ColdFusion array populated with URL instances,
	// we can then cast the ColdFusion array to a typed Java array in
	// order to instantiate the class loader.
	loader = createObject( "java", "java.net.URLClassLoader" ).init(
		javaCast( "java.net.URL[]", urls )
	);

</cfscript>