water.rapids

Class Session

java.lang.Object

water.rapids.Session

public class Session
extends java.lang.Object

Session is a long-lasting environment supporting caching and Copy-On-Write optimization of Vecs. This session may last over many different Rapids calls (provided they refer to the same session). When the session ends, all the cached Vecs will be deleted (except those in user facing Frames).

Constructor Summary

Constructors

Constructor and Description
Session() Constructor

Method Summary

Methods

Modifier and Type	Method and Description
Frame	assign(Key id, Frame src) Update a global ID, maintaining sharing of Vecs
Vec[]	copyOnWrite(Frame fr, int[] cols) Support C-O-W optimizations: the following list of columns are about to be updated.
Val	end(Val returning) Normal session exit.
java.lang.RuntimeException	endQuietly(java.lang.Throwable ex) The Rapids call threw an exception.
Val	exec(AstRoot ast, AstFunction scope) Execute an AstRoot in the current Session with much assertion-checking
void	remove(Frame fr) Remove and delete a session-tracked frame.
Frame	track_tmp(Frame fr) Track a freshly minted tmp frame.

Methods inherited from class java.lang.Object

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

Constructor Detail

Session

public Session()

Constructor

Method Detail

exec

public Val exec(AstRoot ast,
       AstFunction scope)

Execute an AstRoot in the current Session with much assertion-checking

Parameters:

ast - Rapids expression to execute

scope - ?

Returns:

the result from the Rapids expression

end

public Val end(Val returning)

Normal session exit. Returned Frames are fully deep-copied, and are responsibility of the caller to delete. Returned Frames have their refcnts currently up by 1 (for the returned value itself).

endQuietly

public java.lang.RuntimeException endQuietly(java.lang.Throwable ex)

The Rapids call threw an exception. Best-effort cleanup, no more exceptions

track_tmp

public Frame track_tmp(Frame fr)

Track a freshly minted tmp frame. This frame can be removed when the session ends (unlike global frames), or anytime during the session when the client removes it.

remove

public void remove(Frame fr)

Remove and delete a session-tracked frame. Remove from all session tracking spaces. Remove any newly-unshared Vecs, but keep the shared ones.

assign

public Frame assign(Key id,
           Frame src)

Update a global ID, maintaining sharing of Vecs

copyOnWrite

public Vec[] copyOnWrite(Frame fr,
                int[] cols)

Support C-O-W optimizations: the following list of columns are about to be updated. Copy them as-needed and replace in the Frame. Return the updated Frame vecs for flow-coding.