cascading.pipe
Class SubAssembly

java.lang.Object
  cascading.pipe.Pipe
      cascading.pipe.SubAssembly

All Implemented Interfaces:

FlowElement, Traceable, Serializable

Direct Known Subclasses:

AggregateBy, Coerce, Discard, Rename, Retain, Unique

public abstract class SubAssembly
extends Pipe

Subclasses of SubAssembly encapsulate complex assemblies of Pipes so they my be reused in the same manner a Pipe is used.

That is, a typical SubAssembly subclass will accept a 'previous' Pipe instance, and a few arguments for configuring the resulting sub-assembly.

The previous pipe (or pipes) must be passed on the super constructor, or set via setPrevious(Pipe...). This allows the current SubAssembly to become the parent of any Pipe instances between the previous and the tails, exclusive of the previous, and inclusive of the tails.

Subsequently all tail Pipes must be set via the setTails(Pipe...) method.

Note if the SubAssembly represents a split in the pipeline process, all the 'tails' of the assembly must be passed to setTails(Pipe...). It is up the the developer to provide any other access to the tails so they may be chained into any subsequent Pipes.

Any ConfigDef values on this SubAssembly will be honored by child Pipe instances via the Pipe.getParent() back link described above.

See Also:

Serialized Form

Field Summary

Fields inherited from class cascading.pipe.Pipe

configDef, name, parent, stepConfigDef

Constructor Summary

protected	SubAssembly()
protected	SubAssembly(Pipe... previous)
protected	SubAssembly(String name, Pipe[] previous)

Method Summary

String	getName() Get the name of this pipe.
Pipe[]	getPrevious() Get all the upstream pipes this pipe is connected to.
String[]	getTailNames() Method getTailNames returns the tailNames of this SubAssembly object.
Pipe[]	getTails() Method getTails returns all the tails of this SubAssembly object.
protected void	setPrevious(Pipe... previous) Must be called by subclasses to set the start end points of the assembly the subclass represents.
protected void	setTails(Pipe... tails) Must be called by subclasses to set the final end points of the assembly the subclass represents.
static Pipe[]	unwind(Pipe... tails) Is responsible for unwinding nested SubAssembly instances.

Methods inherited from class cascading.pipe.Pipe

equals, getConfigDef, getHeads, getParent, getStepConfigDef, getTrace, hasConfigDef, hashCode, hasStepConfigDef, id, isEquivalentTo, named, names, outgoingScopeFor, pipes, print, printInternal, resolveIncomingOperationArgumentFields, resolveIncomingOperationPassThroughFields, setParent, toString

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

SubAssembly

protected SubAssembly()

SubAssembly

protected SubAssembly(Pipe... previous)

SubAssembly

protected SubAssembly(String name,
                      Pipe[] previous)

Method Detail

unwind

public static Pipe[] unwind(Pipe... tails)

Is responsible for unwinding nested SubAssembly instances.

Parameters:

tails - of type Pipe[]

Returns:

a Pipe[]

setPrevious

protected void setPrevious(Pipe... previous)

Must be called by subclasses to set the start end points of the assembly the subclass represents.

Parameters:

previous - of type Pipe

setTails

protected void setTails(Pipe... tails)

Must be called by subclasses to set the final end points of the assembly the subclass represents.

Parameters:

tails - of type Pipe

getTails

public Pipe[] getTails()

Method getTails returns all the tails of this SubAssembly object. These values are set by setTails(Pipe...).

Returns:

the tails (type Pipe[]) of this SubAssembly object.

getTailNames

public String[] getTailNames()

Method getTailNames returns the tailNames of this SubAssembly object.

Returns:

the tailNames (type String[]) of this SubAssembly object.

getName

public String getName()

Description copied from class: Pipe

Get the name of this pipe. Guaranteed non-null.

Overrides:

getName in class Pipe

Returns:

String the name of this pipe

getPrevious

public Pipe[] getPrevious()

Description copied from class: Pipe

Get all the upstream pipes this pipe is connected to. This method will return the Pipe instances passed on the constructors as inputs to this Pipe instance.

Overrides:

getPrevious in class Pipe

Returns:

all the upstream pipes this pipe is connected to.