Package glide.api.models.commands.scan

Interface ClusterScanCursor

All Known Subinterfaces:

CommandManager.ClusterScanCursorDetail

public interface ClusterScanCursor

A cursor is used to iterate through data returned by cluster SCAN requests.

This interface is used in two ways:

1. An initialCursor() is passed to GenericClusterCommands.scan(glide.api.models.commands.scan.ClusterScanCursor) to start a cluster SCAN request.
2. The result of the GenericClusterCommands.scan(glide.api.models.commands.scan.ClusterScanCursor) call returns a cursor at index 0 of the returned Object[]. This cursor can be supplied again to a call to GenericClusterCommands.scan(glide.api.models.commands.scan.ClusterScanCursor), provided that isFinished() returns false.

Note that cursors returned by GenericClusterCommands.scan(glide.api.models.commands.scan.ClusterScanCursor) may hold external resources. These resources can be released by calling releaseCursorHandle(). However, doing so will invalidate the cursor from being used in another GenericClusterCommands.scan(glide.api.models.commands.scan.ClusterScanCursor).

To do this safely, follow this procedure:

1. Call GenericClusterCommands.scan(glide.api.models.commands.scan.ClusterScanCursor) with the cursor.
2. Call releaseCursorHandle() to destroy the cursor.
3. Assign the new cursor returned by GenericClusterCommands.scan(glide.api.models.commands.scan.ClusterScanCursor).

See Also:

GenericClusterCommands.scan(glide.api.models.commands.scan.ClusterScanCursor)

Example:

 ClusterScanCursor cursor = ClusterScanCursor.initialCursor();
 Object[] result;
 while (!cursor.isFinished()) {
     result = client.scan(cursor).get();
     cursor.releaseCursorHandle();
     cursor = (ClusterScanCursor) result[0];
     Object[] stringResults = (Object[]) result[1];

     System.out.println("\nSCAN iteration:");
     Arrays.asList(stringResults).stream().forEach(i -> System.out.print(i + ", "));
 }
 

Field Summary

Fields

Modifier and Type	Field	Description
static ClusterScanCursor	INITIAL_CURSOR_INSTANCE	The special cursor used to start the first in a series of GenericClusterCommands.scan(glide.api.models.commands.scan.ClusterScanCursor) calls.

Method Summary

Modifier and Type	Method	Description
static ClusterScanCursor	initalCursor()	Deprecated. Use initialCursor() instead.
static ClusterScanCursor	initialCursor()	Creates an empty cursor to be used in the initial GenericClusterCommands.scan(glide.api.models.commands.scan.ClusterScanCursor) call.
boolean	isFinished()	Indicates if this cursor is the last set of data available.
void	releaseCursorHandle()	Releases resources related to this cursor.

Field Detail

INITIAL_CURSOR_INSTANCE

static final ClusterScanCursor INITIAL_CURSOR_INSTANCE

The special cursor used to start the first in a series of GenericClusterCommands.scan(glide.api.models.commands.scan.ClusterScanCursor) calls.

Method Detail

isFinished

boolean isFinished()

Indicates if this cursor is the last set of data available.

If this method returns false, this cursor instance should get passed to GenericClusterCommands.scan(glide.api.models.commands.scan.ClusterScanCursor) to get next set of data.

Returns:

true if this cursor is the last set of data. False if there is potentially more data available.

releaseCursorHandle

void releaseCursorHandle()

Releases resources related to this cursor.

This method can be called to immediately release resources tied to this cursor instance. Note that if this is called, this cursor cannot be used in GenericClusterCommands.scan(glide.api.models.commands.scan.ClusterScanCursor). Also, this method is optional for the caller. If it does not get called, cursor resources will be freed during garbage collection.

initialCursor

static ClusterScanCursor initialCursor()

Creates an empty cursor to be used in the initial GenericClusterCommands.scan(glide.api.models.commands.scan.ClusterScanCursor) call.

initalCursor

@Deprecated
static ClusterScanCursor initalCursor()

Deprecated.

Use initialCursor() instead.

Creates an empty cursor to be used in the initial GenericClusterCommands.scan(glide.api.models.commands.scan.ClusterScanCursor) call.