Package com.datastax.astra.internal.command

Class AbstractCursor<T,R>

java.lang.Object

com.datastax.astra.internal.command.AbstractCursor<T,R>

Type Parameters:

T - working bean of parent table

R - working bean returned for the find

All Implemented Interfaces:

Cloneable, Iterable<R>

Direct Known Subclasses:

CollectionFindAndRerankCursor, CollectionFindCursor, TableFindCursor

public abstract class AbstractCursor<T,R>
extends Object
implements Iterable<R>, Cloneable

Implementation of a cursor across the find items

Field Summary

Fields

Modifier and Type	Field	Description
protected List<R>	buffer	Records to process
protected int	consumed	How many consumed in the current buffer.
protected Page<R>	currentPage	Current page
protected Class<R>	recordType	Type of the row to return
protected CursorState	state	Cursor state.

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	AbstractCursor(Class<R> recordType)	Cursor to iterate on the result of a query.

Method Summary

Modifier and Type	Method	Description
protected void	checkIdleState()	Validate that the cursor is in the IDLE state.
void	close()	Change the state of the cursor to close.
List<R>	consumeBuffer(int n)	Consume the buffer and return the list of items.
protected abstract void	fetchNextBatch()	Fetches the next batch of documents into the buffer.
int	getBufferedSize()	Access the size of the buffer.
Optional<DataAPIVector>	getSortVector()	Access to the Sort Vector.
boolean	hasNext()	Checks if there are more elements in the cursor.
Iterator<R>	iterator()	Iterate over the cursor.
R	next()	Retrieves the next element from the cursor.
void	rewind()	Rewind the cursor to the beginning.
Stream<R>	stream()	Convert the current cursor as a stream
List<R>	toList()	Collects all remaining elements in the cursor into a list.

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.lang.Iterable

forEach, spliterator

Field Details

state

protected CursorState state

Cursor state.

buffer

protected List<R> buffer

Records to process

currentPage

protected Page<R> currentPage

Current page

consumed

protected int consumed

How many consumed in the current buffer.

recordType

protected Class<R> recordType

Type of the row to return

Constructor Details

AbstractCursor

protected AbstractCursor(Class<R> recordType)

Cursor to iterate on the result of a query.

Parameters:

recordType - row type returned with the cursor

Method Details

close

public void close()

Change the state of the cursor to close.

rewind

public void rewind()

Rewind the cursor to the beginning.

consumeBuffer

public List<R> consumeBuffer(int n)

Consume the buffer and return the list of items.

Parameters:

n - number of items to consume

Returns:

list of items

checkIdleState

protected void checkIdleState()

Validate that the cursor is in the IDLE state.

iterator

public Iterator<R> iterator()

Iterate over the cursor.

Specified by:

iterator in interface Iterable<T>

Returns:

iterator over the results

fetchNextBatch

protected abstract void fetchNextBatch()

Fetches the next batch of documents into the buffer. This method handles paging, using the page state from the previous batch to fetch the next one.

hasNext

public boolean hasNext()

Checks if there are more elements in the cursor.

Returns:

true if there are more elements, false otherwise

next

public R next()

Retrieves the next element from the cursor.

Returns:

the next element of type R

Throws:

NoSuchElementException - if no more elements are available

toList

public List<R> toList()

Collects all remaining elements in the cursor into a list. Automatically closes the cursor after all elements are consumed.

Returns:

a List containing all remaining elements

stream

public Stream<R> stream()

Convert the current cursor as a stream

Returns:

current as a stream

getBufferedSize

public int getBufferedSize()

Access the size of the buffer.

Returns:

buffer count

getSortVector

public Optional<DataAPIVector> getSortVector()

Access to the Sort Vector.

Returns:

sort vector