com.amazon.carbonado.cursor

Class AbstractCursor<S>

java.lang.Object

com.amazon.carbonado.cursor.AbstractCursor<S>

All Implemented Interfaces:

Cursor<S>

Direct Known Subclasses:

ControllerCursor, DifferenceCursor, FetchAheadCursor, FilteredCursor, GroupedCursor, IntersectionCursor, IteratorCursor, LimitCursor, MultiTransformedCursor, RawCursor, SkipCursor, SortedCursor, SymmetricDifferenceCursor, ThrottledCursor, TransformedCursor, UnionCursor

public abstract class AbstractCursor<S>
extends java.lang.Object
implements Cursor<S>

AbstractCursor implements a small set of common Cursor methods.

Author:

Brian S O'Neill

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	AbstractCursor()

Method Summary

Methods

Modifier and Type	Method and Description
int	copyInto(java.util.Collection<? super S> c) Copies all remaining next elements into the given collection.
int	copyInto(java.util.Collection<? super S> c, int limit) Copies a limited amount of remaining next elements into the given collection.
int	skipNext(int amount) Skips forward by the specified amount of elements, returning the actual amount skipped.
java.util.List<S>	toList() Copies all remaining next elements into a new modifiable list.
java.util.List<S>	toList(int limit) Copies a limited amount of remaining next elements into a new modifiable list.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface com.amazon.carbonado.Cursor

close, hasNext, next

Constructor Detail

AbstractCursor

protected AbstractCursor()

Method Detail

copyInto

public int copyInto(java.util.Collection<? super S> c)
             throws FetchException

Description copied from interface: Cursor

Copies all remaining next elements into the given collection. This method is roughly equivalent to the following:

 Cursor cursor;
 ...
 while (cursor.hasNext()) {
     c.add(cursor.next());
 }
 

As a side-effect of calling this method, the cursor is closed.

Specified by:

copyInto in interface Cursor<S>

Returns:

actual amount of results added

Throws:

FetchException - if storage layer throws an exception

copyInto

public int copyInto(java.util.Collection<? super S> c,
           int limit)
             throws FetchException

Description copied from interface: Cursor

Copies a limited amount of remaining next elements into the given collection. This method is roughly equivalent to the following:

 Cursor cursor;
 ...
 while (--limit >= 0 && cursor.hasNext()) {
     c.add(cursor.next());
 }
 

Specified by:

copyInto in interface Cursor<S>

limit - maximum amount of elements to copy

Returns:

actual amount of results added

Throws:

FetchException - if storage layer throws an exception

toList

public java.util.List<S> toList()
                         throws FetchException

Description copied from interface: Cursor

Copies all remaining next elements into a new modifiable list. This method is roughly equivalent to the following:

 Cursor<S> cursor;
 ...
 List<S> list = new ...
 cursor.copyInto(list);
 

As a side-effect of calling this method, the cursor is closed.

Specified by:

toList in interface Cursor<S>

Returns:

a new modifiable list

Throws:

FetchException - if storage layer throws an exception

toList

public java.util.List<S> toList(int limit)
                         throws FetchException

Description copied from interface: Cursor

Copies a limited amount of remaining next elements into a new modifiable list. This method is roughly equivalent to the following:

 Cursor<S> cursor;
 ...
 List<S> list = new ...
 cursor.copyInto(list, limit);
 

Specified by:

toList in interface Cursor<S>

Parameters:

limit - maximum amount of elements to copy

Returns:

a new modifiable list

Throws:

FetchException - if storage layer throws an exception

skipNext

public int skipNext(int amount)
             throws FetchException

Description copied from interface: Cursor

Skips forward by the specified amount of elements, returning the actual amount skipped. The actual amount is less than the requested amount only if the end of the results was reached.

Specified by:

skipNext in interface Cursor<S>

Parameters:

amount - maximum amount of elements to skip

Returns:

actual amount skipped

Throws:

FetchException - if storage layer throws an exception