Databoard Snippets

This document contains a some Java coding snippets for the Databoard library.

The binding class can be used for cloning objects. All copied objects are deep. Mutable objects are duplicated, and immutable are referenced.

	// Binding can copy objects. All copies are deep. 
	// Mutable objects are duplicated, immutable are referenced.
		
	// For instance, in object array, the array is copied, but its
	// immutable literal instances (e.g. 1) is referenced.
		
	Object[] original = new Object[] { 1, "X", 123.456 };
	Binding binding = Bindings.getBinding( original.getClass() );
	Object[] copy = (Object[]) binding.cloneUnchecked( original );

	// Print the objects
	System.out.println( "Original: "+binding.toString( original ) );
	System.out.println( "Clone   : "+binding.toString( copy     ) );    

Recursive classes can also be cloned, but they must be annotated with @Referable tag.

static @Referable class X {
	public X reference;
}
	
public static void main(String[] args) throws BindingConstructionException, BindingException {
	// Create recursive instance
	X original = new X();
	original.reference = original;
		
	Binding binding = Bindings.getBinding( original.getClass() );
	X copy = (X) binding.cloneUnchecked( original );

	// Print the objects
	System.out.println( "Original: "+binding.toString( original ) );
	System.out.println( "Clone   : "+binding.toString( copy     ) );
}

Binding can compare any two instances. The compare function is deep.

	Binding binding = Bindings.getBindingUnchecked( int[].class );
		
	int[] array1 = new int[] { 1, 2, 3 };
	int[] array2 = new int[] { 1, 2, 3 };
	int[] array3 = new int[] { 2, 3, 4 };
		
	if ( binding.compare(array1, array2) == 0 ) {
		System.out.println( "array1 is equal to array2" );
	} else {
		System.out.println( "array1 is not equal to array2" );
	}
		
	if ( binding.compare(array1, array3) == 0 ) {
		System.out.println( "array1 is equal to array3" );
	} else {
		System.out.println( "array1 is not equal to array3" );
	}

Two bindings can compare instances of same datatype, even if they are of different classes.

	ArrayList<Integer> array4 = new ArrayList<Integer>();
	Binding binding2 = Bindings.getBindingUnchecked( ArrayList.class, Integer.class );
	array4.add( 1 );
	array4.add( 2 );
	array4.add( 3 );
		
	if ( Bindings.compare(binding, array1, binding2, array4) == 0 ) {
		System.out.println( "array1 is equal to array4" );
	} else {
		System.out.println( "array1 is not equal to array4" );
	}

Binding can calculate deep hashcode for any instance

	Binding binding = Bindings.getBindingUnchecked( int[].class );
		
	int[] array1 = new int[] { 1, 2, 3 };
	int[] array2 = new int[] { 1, 2, 3 };
	int[] array3 = new int[] { 2, 3, 4 };
		
	System.out.println( "Hashcode for array1 is " + binding.hashValue( array1 ) );
	System.out.println( "Hashcode for array2 is " + binding.hashValue( array2 ) );
	System.out.println( "Hashcode for array3 is " + binding.hashValue( array3 ) );