org.apache.ignite.internal.cache.query.index

Class SingleCursor<T>

java.lang.Object

org.apache.ignite.internal.cache.query.index.SingleCursor<T>

Type Parameters:

T - class of value to return.

All Implemented Interfaces:

GridCursor<T>

public class SingleCursor<T>
extends Object
implements GridCursor<T>

Cursor that holds single value only.

Constructor Summary

Constructors

Constructor and Description
SingleCursor(T val)

Method Summary

Modifier and Type	Method and Description
T	get() Note that this implementation violates the contract of GridCusror.
boolean	next() Attempt to move cursor position forward.

Methods inherited from class java.lang.Object

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

Constructor Detail

SingleCursor

public SingleCursor(T val)

Method Detail

next

public boolean next()

Attempt to move cursor position forward.

Specified by:

next in interface GridCursor<T>

Returns:

true If we were able to move position of cursor forward.

get

public T get()
      throws IgniteCheckedException

Note that this implementation violates the contract of GridCusror. It must be "before first" but this implementation handles both cases: "before first" and "on first". Current implementation of SQL with H2 relies on this null for queries like "select max(col) from table". This should be fixed for other SQL engines. https://issues.apache.org/jira/browse/IGNITE-14303.

Specified by:

get in interface GridCursor<T>

Returns:

Element at current position.

Throws:

IgniteCheckedException - If failed.