water.rapids

Class Env

java.lang.Object

water.Iced

water.rapids.Env

All Implemented Interfaces:

java.io.Externalizable, java.io.Serializable, java.lang.Cloneable, Freezable

public class Env
extends Iced

Execute a set of instructions in the context of an H2O cloud.

An Env (environment) object is a classic stack of values used during execution of an AstRoot. The stack is hidden in the normal Java execution stack and is not explicit.

For efficiency, reference counting is employed to recycle objects already in use rather than creating copies upon copies (a la R). When a Frame is `pushed` on to the stack, its reference count is incremented by 1. When a Frame is `popped` off of the stack, its reference count is decremented by 1. When the reference count is 0, the Env instance will dispose of the object. All objects live and die by the Env's that create them. That means that any object not created by an Env instance shalt not be DKV.removed.

Therefore, the Env class is a stack of values + an API for reference counting.

See Also:

Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
class	Env.StackHelp

Field Summary

Fields

Modifier and Type	Field and Description
AstFunction	_scope
Session	_ses

Constructor Summary

Constructors

Constructor and Description
Env(Session ses)

Method Summary

Modifier and Type	Method and Description
java.lang.String	expand(java.lang.String id)
Val	lookup(java.lang.String id)
<V extends Val> V	returning(V val)
int	sp()
Env.StackHelp	stk()
java.lang.String	toString()

Methods inherited from class water.Iced

asBytes, clone, copyOver, frozenType, read, readExternal, readJSON, reloadFromBytes, toJsonBytes, toJsonString, write, writeExternal, writeJSON

Methods inherited from class java.lang.Object

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

Field Detail

_ses

public final Session _ses

_scope

public AstFunction _scope

Constructor Detail

Env

public Env(Session ses)

Method Detail

sp

public int sp()

stk

public Env.StackHelp stk()

returning

public <V extends Val> V returning(V val)

lookup

public Val lookup(java.lang.String id)

expand

public java.lang.String expand(java.lang.String id)

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object