org.shapelogic.streams
Class BaseListCommonStream<E>

java.lang.Object
  org.shapelogic.streams.BaseListCommonStream<E>

All Implemented Interfaces:

java.lang.Iterable<E>, java.util.Iterator<E>, CalcValue<E>, ContextGettable, InContexts, LazyCalc<E>, ListStream<E>, NumberedStream<E>, Stream<E>, StreamProperties

Direct Known Subclasses:

BaseListIndexedStream1, BaseListStream0, BaseListStream1, BaseListStream2, BaseListStreamList, SingleListStream

public abstract class BaseListCommonStream<E>
extends java.lang.Object
implements ListStream<E>, StreamProperties, ContextGettable

Implementation of ListStream.
Close to
1: a lazy stream.
2: a UNIX pipe.

This is close to org.apache.commons.collections.list.LazyList, but that takes a factory to calculate next element, and that works badly here. How should a step work?
Normally call the hasNext, in order for this to work it would have to do the calculation.

So _current should be the last element that has been returned.

So when you call hasNext it will add that element to the list. When you call next it will bump the counter up one element if goes too high then do the calculation. At the end it will get to a point where the calculation fails. At that point last will be set to the current element. I will ignore synchronization to begin with.

Author:

Sami Badawi

Field Summary

protected java.util.Map[]	_contexts
protected int	_current The last value that was calculated and looked at So if you want to see that again use this for a lookup
protected boolean	_dirty
protected int	_last Last value that can be calculated.
protected java.util.List<E>	_list
protected int	_maxLast Highest value that last can take.
protected java.lang.String	_name Does not always exist.
protected IQueryCalc	_query
protected E	_value

Constructor Summary

BaseListCommonStream()

Method Summary

protected boolean	calcAddNext() Try to calculate one more, independent of the _current.
E	get(int arg0) Get next element without advancing _current.
java.util.Map	getContext() The context if needed.
java.util.Map[]	getContexts()
int	getCurrentSize()
java.lang.Object	getInContext(java.lang.Object key)
int	getIndex() Index of last successfully processed element.
int	getLast() Last possible element.
java.util.List<E>	getList() Get underlying list.
int	getMaxLast() Set a max value for last possible element.
java.lang.String	getName() If a stream has a name.
E	getValue() Starts a lazy calculation.
boolean	hasNext()
boolean	hasNextBase()
abstract E	invokeIndex(int index) Calculate the value at an index.
boolean	isCached() If there is a list that contains all the results.
boolean	isContextBased() If it needs a context.
boolean	isDeterministic() Is the result of a calculation deterministic.
boolean	isDirty() When dirty is false that means that the calculated value can be used
boolean	isRandomAccess() If you can calculate 1 element independent of other elements.
java.util.Iterator<E>	iterator()
E	next() Get next element and advance _current.
void	remove()
void	setList(java.util.List<E> list) Get underlying list.
void	setMaxLast(int maxLast) Set a max value for last possible element.
void	setup() Currently not super well define used for 2 purposes: Reset: called from the outside if you want to reuse it init: Called from the inside when calculation start to have everything setup maybe the semantic could work for both? TODO: This should be separated better.

Methods inherited from class java.lang.Object

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

Field Detail

_list

protected java.util.List<E> _list

_current

protected int _current

The last value that was calculated and looked at So if you want to see that again use this for a lookup

_last

protected int _last

Last value that can be calculated. When _maxLast is set then _last should first be set to the same. If lower limit is found move down.

_maxLast

protected int _maxLast

Highest value that last can take.

_name

protected java.lang.String _name

Does not always exist.

_dirty

protected boolean _dirty

_value

protected E _value

_contexts

protected java.util.Map[] _contexts

_query

protected IQueryCalc _query

Constructor Detail

BaseListCommonStream

public BaseListCommonStream()

Method Detail

invokeIndex

public abstract E invokeIndex(int index)

Calculate the value at an index.
So it gets the needed input value and call the appropriate invoke function.
Can this be used for a filter call?
The index does not make sense for a filter since you do not know where the input is coming from. So maybe just ignore it.
This is a little messy but less messy that what is there now.

hasNext

public boolean hasNext()

Specified by:

hasNext in interface java.util.Iterator<E>

calcAddNext

protected boolean calcAddNext()

Try to calculate one more, independent of the _current.

hasNextBase

public boolean hasNextBase()

next

public E next()

Get next element and advance _current.

Specified by:

next in interface java.util.Iterator<E>

get

public E get(int arg0)

Get next element without advancing _current.

Specified by:

get in interface NumberedStream<E>

Returns:

getLast

public int getLast()

Description copied from interface: NumberedStream

Last possible element.

Specified by:

getLast in interface NumberedStream<E>

getMaxLast

public int getMaxLast()

Description copied from interface: NumberedStream

Set a max value for last possible element.

Specified by:

getMaxLast in interface NumberedStream<E>

setMaxLast

public void setMaxLast(int maxLast)

Set a max value for last possible element. This also set last.

Specified by:

setMaxLast in interface NumberedStream<E>

isRandomAccess

public boolean isRandomAccess()

Description copied from interface: StreamProperties

If you can calculate 1 element independent of other elements.

Specified by:

isRandomAccess in interface StreamProperties

isCached

public boolean isCached()

If there is a list that contains all the results.

Specified by:

isCached in interface StreamProperties

getCurrentSize

public int getCurrentSize()

getList

public java.util.List<E> getList()

Description copied from interface: ListStream

Get underlying list.

Specified by:

getList in interface ListStream<E>

setList

public void setList(java.util.List<E> list)

Description copied from interface: ListStream

Get underlying list.

Specified by:

setList in interface ListStream<E>

getIndex

public int getIndex()

Description copied from interface: NumberedStream

Index of last successfully processed element.

Specified by:

getIndex in interface NumberedStream<E>

getName

public java.lang.String getName()

Description copied from interface: StreamProperties

If a stream has a name.

Specified by:

getName in interface StreamProperties

setup

public void setup()

Description copied from interface: LazyCalc

Currently not super well define used for 2 purposes: Reset: called from the outside if you want to reuse it init: Called from the inside when calculation start to have everything setup maybe the semantic could work for both? TODO: This should be separated better.

Specified by:

setup in interface LazyCalc<E>

getContext

public java.util.Map getContext()

Description copied from interface: StreamProperties

The context if needed. Maybe it would be better to make a link to the task that contains the context.

Specified by:

getContext in interface StreamProperties

getValue

public E getValue()

Description copied from interface: CalcValue

Starts a lazy calculation. If dirty do calc() else return cached value. This should maybe be moved up in the hierarchy

Specified by:

getValue in interface CalcValue<E>

isContextBased

public boolean isContextBased()

Description copied from interface: StreamProperties

If it needs a context.

Specified by:

isContextBased in interface StreamProperties

isDeterministic

public boolean isDeterministic()

Description copied from interface: StreamProperties

Is the result of a calculation deterministic.

Specified by:

isDeterministic in interface StreamProperties

isDirty

public boolean isDirty()

Description copied from interface: LazyCalc

When dirty is false that means that the calculated value can be used

Specified by:

isDirty in interface LazyCalc<E>

remove

public void remove()

Specified by:

remove in interface java.util.Iterator<E>

iterator

public java.util.Iterator<E> iterator()

Specified by:

iterator in interface java.lang.Iterable<E>

getContexts

public java.util.Map[] getContexts()

Specified by:

getContexts in interface InContexts

getInContext

public java.lang.Object getInContext(java.lang.Object key)

Specified by:

getInContext in interface ContextGettable