org.jclarion.clarion.view
Class ClarionView

java.lang.Object
  org.jclarion.clarion.PropertyObject
      org.jclarion.clarion.view.ClarionView

All Implemented Interfaces:

ViewField

public class ClarionView
extends PropertyObject
implements ViewField

Model a clarion view Some observations from experiments with views in clarion 5.5 and resulting SQL sent to postgres: When no order is indicated - select is not sorted Use of positioning etc has not effect reset will reset from top Ordering is critical for positioning etc. Clarion assumes that order defines a unique position. We will too changes to prop:order take effect on next set() Calling reset(view,file) will trigger reset based on position inferred in file buffers taking changes to prop:order etc into consideration. Clarion also forces a read on the table(s) in question ( their primary keys?) Calling reset(view,int) does *not* do what clarion documentation implies and what I originally coded this object to do. Calling reset is very similar to calling reset(view,file) except trailing fields in key are zeroed out calling getposition(), change prop:order call reset(view,string) works same as above. Clarion must be encoding more than just ordering data. From help files - clarion says it encodes data relating to primary key fields. So position for views encodes PK data only. Presumably - this is all view needs - pk data. Everything else can be derived from there. All fields in a table that are keyed are implicitly included as part of the project list reget must call get on every underlying file Implementation of this is to just create a dynamic ClarionSQLFile object with an overloaded open() method where we synthesize the FileState object to represent a more sophisticated table structure and then methods like next() etc here become simple wrappers for the underlying dynamically create file Items: Limitiations: * Will not handle having tables appear more than once in structre Clarion system did not handle this well either - i.e. no way to differentiate tables thus selected. * no intention of implementing mutators like put() etc just yet. to do this: 1) save changed params. Call reget() on primary file Restroe changed params. put() * outer joins and positions will not work due to absence of facility to record position of nullable parameters in ClarionSQLFile right now. Is doable - but tricky because of fact that comparators in ANSI SQL do not play nice with nullable columns * will only work for all File types are SQL * will only work if all file types share same source TODO - implement view solution that can cross non SQL implementations and different sources.

Author:

barney

Constructor Summary

ClarionView()

Method Summary

void	add(ViewJoin aTable)
void	add(ViewProject aProject)
void	buffer(java.lang.Integer pagesize, java.lang.Integer behind, java.lang.Integer ahead, java.lang.Integer timeout)
void	close()
protected void	debugMetaData(java.lang.StringBuilder sb)
void	delete()
void	flush()
ClarionObject	getField()
ClarionFile	getFile(int indx)
ClarionFile	getFileForField(int indx)
int	getFileIndexForField(int indx)
ClarionObject	getLocalProperty(int index)
PropertyObject	getParentPropertyObject()
ClarionString	getPosition()
java.lang.Iterable<ViewField>	getSubFields()
protected void	iterate(int dir)
void	next()
protected void	notifyLocalChange(int indx, ClarionObject value)
void	open()
void	previous()
void	put()
int	records() Not really clear when is a good time to call records Should we regenerate filters as part of record get or assume this has already happened? Will err on side of no regeneration.
void	reget(ClarionString position)
void	reset(ClarionFile position) Reset based on current order parameter's directly from ClarionFile buffers
void	reset(ClarionString position) Reset based on indicated position Essentially - reget() following by a reset(file)
void	set()
void	set(int sortOffset)
void	setFilter(java.lang.String filter)
void	setOrder(java.lang.String order)
void	setTable(ClarionFile aFile)
void	watch()

Methods inherited from class org.jclarion.clarion.PropertyObject

addListener, canNotifyLocalChange, clearMetaData, debugMetaData, getDebugMetaData, getDebugMetaData, getId, getInheritedProperty, getProperty, getProperty, getProperty, getProperty, getPropertyOrDefault, getRawProperty, getRawProperty, getSetProperties, isProperty, isSettable, reMap, removeAllListeners, removeListener, setClonedProperty, setClonedProperty, setClonedProperty, setClonedProperty, setClonedProperty, setId, setProperty, setProperty, setProperty, setProperty, setProperty, toString

Methods inherited from class java.lang.Object

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

Constructor Detail

ClarionView

public ClarionView()

Method Detail

add

public void add(ViewJoin aTable)

add

public void add(ViewProject aProject)

setTable

public void setTable(ClarionFile aFile)

setOrder

public void setOrder(java.lang.String order)

setFilter

public void setFilter(java.lang.String filter)

open

public void open()

close

public void close()

delete

public void delete()

put

public void put()

set

public void set()

flush

public void flush()

records

public int records()

Not really clear when is a good time to call records Should we regenerate filters as part of record get or assume this has already happened? Will err on side of no regeneration. Another problem - what about client side filters? They will not be taken into consideration. Will consider this one to be ok - if anyone wants an accurate count of actual records - they need to iterate over them

Returns:

set

public void set(int sortOffset)

next

public void next()

iterate

protected void iterate(int dir)

watch

public void watch()

getPosition

public ClarionString getPosition()

reset

public void reset(ClarionString position)

Reset based on indicated position Essentially - reget() following by a reset(file)

Parameters:

position -

reget

public void reget(ClarionString position)

reset

public void reset(ClarionFile position)

Reset based on current order parameter's directly from ClarionFile buffers

Parameters:

position -

previous

public void previous()

buffer

public void buffer(java.lang.Integer pagesize,
                   java.lang.Integer behind,
                   java.lang.Integer ahead,
                   java.lang.Integer timeout)

getFile

public ClarionFile getFile(int indx)

getParentPropertyObject

public PropertyObject getParentPropertyObject()

Specified by:

getParentPropertyObject in class PropertyObject

getLocalProperty

public ClarionObject getLocalProperty(int index)

Overrides:

getLocalProperty in class PropertyObject

notifyLocalChange

protected void notifyLocalChange(int indx,
                                 ClarionObject value)

Overrides:

notifyLocalChange in class PropertyObject

getFileForField

public ClarionFile getFileForField(int indx)

getFileIndexForField

public int getFileIndexForField(int indx)

debugMetaData

protected void debugMetaData(java.lang.StringBuilder sb)

Specified by:

debugMetaData in class PropertyObject

getField

public ClarionObject getField()

Specified by:

getField in interface ViewField

getSubFields

public java.lang.Iterable<ViewField> getSubFields()

Specified by:

getSubFields in interface ViewField