com.yworks.yfiles.utils

Interface IEnumerator<T>

Type Parameters:

T - The type of the elements in this enumerator.

All Superinterfaces:

AutoCloseable, IDisposable

public interface IEnumerator<T>
extends IDisposable

An enumerator over a collection. Enumerators have a different semantic than Iterator and Enumeration. One difference is that IEnumerator is read-only. Another difference is that enumerators provide a method to restart the iteration over a collection called reset(). Other differences are in the semantics of the iteration methods.

Field Summary

Fields

Modifier and Type	Field and Description
static IEnumerator	EMPTY An IEnumerator that is always empty.

Method Summary

Modifier and Type	Method and Description
static <T> IEnumerator<T>	concat(IEnumerator<? extends T> first, IEnumerator<? extends T> second) Creates a composite enumerator that enumerates two given enumerators one after the other.
T	current() Returns the item at the current position of this enumerator.
boolean	moveNext() Increments the current position by 1.
void	reset() Resets the position of the pointer to its initial state.
default Object[]	toArray(IEnumerator<T> e, int size) Similar to Collection.toArray(), this method creates an array that contains the items of the given IEnumerator.
default <E> E[]	toArray(IEnumerator<T> e, int size, E[] a) Similar to Collection.toArray(Object[]), this method creates an array that contains the items of the given IEnumerator.

Methods inherited from interface com.yworks.yfiles.utils.IDisposable

close, dispose

Field Detail

EMPTY

static final IEnumerator EMPTY

An IEnumerator that is always empty.

Method Detail

concat

static <T> IEnumerator<T> concat(IEnumerator<? extends T> first,
                                 IEnumerator<? extends T> second)

Creates a composite enumerator that enumerates two given enumerators one after the other.

Parameters:

first - The first one.

second - The second one.

Returns:

An IEnumerator which enumerate of the first enumerator and then over the second.

current

T current()

Returns the item at the current position of this enumerator.

Calling this method does not move the pointer. Thus, it is possible to retrieve the same item multiple times with subsequent calls to this method.

Important: The initial position of the pointer is before the first item (equal to -1), so moveNext() must be called prior to this method at least once. If this method is called before an initial moveNext(), the result of this method is undefined or it may even throw an exception.

moveNext

boolean moveNext()

Increments the current position by 1. Returns true if an item can be safely retrieved via current() after this call.

If this method returns false, result of current() is undefined or it may even throw an exception.

reset

void reset()

Resets the position of the pointer to its initial state. Thus, before calling current(), moveNext() must be called after calling this method.

toArray

default Object[] toArray(IEnumerator<T> e,
                         int size)

Similar to Collection.toArray(), this method creates an array that contains the items of the given IEnumerator.

Note:
In contrary to the counterpart defined in Collection, this method throws a ClassCastException if T cannot be cast to E instead of an ArrayStoreException.

Throws:

ClassCastException - if T cannot be cast to E

ArrayIndexOutOfBoundsException - if size is smaller than the actual size of the enumerator

Parameters:

size - The size of the enumerator

Returns:

An array that is at least size big and contains all elements of the enumerator.

toArray

default <E> E[] toArray(IEnumerator<T> e,
                        int size,
                        E[] a)

Similar to Collection.toArray(Object[]), this method creates an array that contains the items of the given IEnumerator.

Note:
In contrary to the counterpart defined in Collection, this method throws a ClassCastException if T cannot be cast to E instead of an ArrayStoreException.

Throws:

ClassCastException - if T cannot be cast to E

ArrayIndexOutOfBoundsException - if size is smaller than the actual size of the enumerator

Parameters:

size - The size of the enumerator

a - The array to store the items in. Note: If the array is to small, then a new array is created and returned.

Returns:

An array that is at least size big and contains all elements of the enumerator.