com.mapinfo.midev.feature

Interface IFeatureIterator

All Known Subinterfaces:

ICursor

public interface IFeatureIterator

An iterator over IFeatures.

It is important to note that when done with an IFeatureIterator that its IFeatureIterator.dispose() method be called or a potential resource leak may occur. A typical pattern for using an IFeatureIterator is as follows:

// this assumes there is an iterator() method returning an IFeatureIterator
IFeatureIterator iterator = iterator();
try {
    while (iterator.hasNext()) {
        IFeature feature = iterator.next();
        // do something with each feature
    }
} finally {
    iterator.dispose();
}

Method Summary

Modifier and Type	Method and Description
void	dispose() Disposes of the resources held by this feature iterator.
default void	forEachRemaining(Consumer action) Performs the given action for each remaining feature in this feature iterator until all features have been processed or the action throws an exception.
boolean	hasNext() Returns true if next will return a feature; false if it will throw an exception.
boolean	isDisposed() Returns true if this feature iterator has been closed; false if not.
boolean	isTransient() Returns true if this feature iterator will produce transient features; false if not.
IFeature	next() Returns the next feature from this feature iterator.
default void	remove() Removes the most recently returned feature from next.

Method Detail

next

IFeature next()

Returns the next feature from this feature iterator.

Returns:

the next feature from this feature iterator.

Throws:

NoSuchElementException - iteration has no more elements.

IllegalStateException - if this feature iterator has been disposed.

dispose

void dispose()

Disposes of the resources held by this feature iterator. Feature iterators are intended to be used as forward-only accessors to a set of feature instances.

It is good practice to always dispose of a feature iterator (including implementations of ICursor) to indicate that it may release its resources. In some cases, such as when the iterator is managing a database cursor, it is required to release the resources so that the database connection may be reused.

Calling dispose on an iterator that has already been disposed does not throw an exception.

isDisposed

boolean isDisposed()

Returns true if this feature iterator has been closed; false if not.

Returns:

true if this feature iterator has been closed; false if not.

isTransient

boolean isTransient()

Returns true if this feature iterator will produce transient features; false if not.

Returns:

true if this feature iterator will produce transient features; false if not.

Throws:

IllegalStateException - if this feature iterator has been disposed.

hasNext

boolean hasNext()

Returns true if next will return a feature; false if it will throw an exception.

Returns:

true if next will return a feature; false if it will throw an exception.

Throws:

IllegalStateException - if this feature iterator has been disposed.

remove

default void remove()

Removes the most recently returned feature from next. This is an optional operation.

The default implementation throws an instance of UnsupportedOperationException and performs no other action.

Throws:

UnsupportedOperationException - if the remove operation is not supported by this feature iterator.

IllegalStateException - if next() has not been called or this feature iterator has been disposed.

forEachRemaining

default void forEachRemaining(Consumer action)

Performs the given action for each remaining feature in this feature iterator until all features have been processed or the action throws an exception. The feature iterator will be disposed when returned. Exceptions thrown by the action are relayed to the caller.

The default implementation behaves as if:

 
        try {
          while (hasNext()) {
            action.accept(next());
          }
        } finally {
          dispose();
        }
 

Parameters:

action - The action to be performed for each IFeature

Throws:

NullPointerException - if the specified action is null

IllegalStateException - if this feature iterator has been disposed.