Package com.storedobject.core

Class LedgerWindow

java.lang.Object

com.storedobject.core.LedgerWindow

public class LedgerWindow
extends Object

Representation of a "window" of entries (instances of LedgerEntry) of the "Transaction Ledger". A List must be provided to keep the entries and this class will maintain that list by adding/removing entries to/from it when the "window" is moved forward/backward. When the instance is initialized with an Account, it will automatically load entries corresponding to the latest transactions.

Note: Please note that this class doesn't support generic ledger entries of external systems unless you override methods: getLedger(Date, Date), getMaxDate(Date), getMinDate(Date). However, there is a provision to append additional entries (could be un-posted ones). Override the getUnposted() method for returning the unposted entries. All the entries in the unposted entry list must have the same date, and it will be automatically fixed as the upper date boundary.

Author:

Syam

Constructor Summary

Constructors

Constructor	Description
LedgerWindow()	Constructor.
LedgerWindow(int windowSize)	Constructor.
LedgerWindow(int windowSize, List<LedgerEntry> entries)	Constructor.
LedgerWindow(List<LedgerEntry> entries)	Constructor.

Method Summary

Modifier and Type	Method	Description
boolean	canMoveBackward()	Can we move backward?
boolean	canMoveForward()	Can we move forward?
Account	getAccount()	Get the account for which entries are loaded.
List<LedgerEntry>	getEntries()	Get the list containing the ledger entries.
Ledger	getLedger(Date from, Date to)	Get the ledger entries for the given period for the account.
Date	getMaxDate(Date upperBoundary)	Get the date of the most recent transaction within the upper boundary.
Date	getMinDate(Date lowerBoundary)	Get the date of the first transaction available for the current account.
protected List<LedgerEntry>	getUnposted()	Override this method to return any unposted entries to be appended.
boolean	isError()	Check if any DB error occurred while loading entries or not.
boolean	moveBackward()	Move the window backward.
boolean	moveForward()	Move the window forward.
void	moveToBeginning()	Move window to the beginning.
void	moveToEnd()	Move window to the end.
void	setAccount(Account account)	Set the account for which ledger entries need to be loaded.
void	setAccount(Account account, Date date)	Set the account for which ledger entries need to be loaded.
void	setDate(Date date)	Set the starting date from which ledger entries to be loaded.
void	setErrorLogger(ErrorLogger errorLogger)	Set the error logger to capture the errors while generating the ledger entries.

Methods inherited from class java.lang.Object

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

Constructor Details

LedgerWindow

public LedgerWindow()

Constructor. Default window size is 10.

LedgerWindow

public LedgerWindow(List<LedgerEntry> entries)

Constructor. Default window size is 10.

Parameters:

entries - List where ledger entries need to be maintained. If null is passed, a new list will be created.

LedgerWindow

public LedgerWindow(int windowSize)

Constructor.

Parameters:

windowSize - Window size of the ledger entries.

LedgerWindow

public LedgerWindow(int windowSize,
 List<LedgerEntry> entries)

Constructor.

Parameters:

windowSize - Window size of the ledger entries.

entries - List where ledger entries need to be maintained. If null is passed, a new list will be created.

Method Details

getEntries

public List<LedgerEntry> getEntries()

Get the list containing the ledger entries. The list returned by this method should not be altered externally. If altered, further method calls may not work properly.

Returns:

List.

getAccount

public Account getAccount()

Get the account for which entries are loaded.

Returns:

Account.

setAccount

public void setAccount(Account account)

Set the account for which ledger entries need to be loaded. Ledger entries for the most recent transactions will be loaded.

Parameters:

account - Account.

setAccount

public void setAccount(Account account,
 Date date)

Set the account for which ledger entries need to be loaded.

Parameters:

account - Account.

date - Date for which entries need to be loaded. If passed null, most recent entries will be loaded.

setDate

public void setDate(Date date)

Set the starting date from which ledger entries to be loaded. If enough entries are not found to fill up the window-size, it will try to load more entries from the following dates until window-size can be full-filled. If there are no entries in the following dates to full-fill the window-size, it will try load entries from the preceding dates to full-fill the window-size. If null is passed, the entries corresponding to the latest transactions are loaded.

Parameters:

date - Starting date.

canMoveBackward

public boolean canMoveBackward()

Can we move backward?

Returns:

True/false.

canMoveForward

public boolean canMoveForward()

Can we move forward?

Returns:

True/false.

moveToBeginning

public void moveToBeginning()

Move window to the beginning.

moveToEnd

public void moveToEnd()

Move window to the end.

moveBackward

public boolean moveBackward()

Move the window backward.

Returns:

True if moved and false if no further ledger entries found.

moveForward

public boolean moveForward()

Move the window forward.

Returns:

True if moved and false if no further ledger entries found.

isError

public boolean isError()

Check if any DB error occurred while loading entries or not.

Returns:

True or false.

getUnposted

protected List<LedgerEntry> getUnposted()

Override this method to return any unposted entries to be appended.

Returns:

Unposted entries.

setErrorLogger

public void setErrorLogger(ErrorLogger errorLogger)

Set the error logger to capture the errors while generating the ledger entries.

Parameters:

errorLogger - Error logger.

getMinDate

public Date getMinDate(Date lowerBoundary)

Get the date of the first transaction available for the current account. Override this method if you override getLedger(Date, Date) to bring entries from an external system.

Parameters:

lowerBoundary - Lower boundary. If not null, the date returned should be greater than or equal to this. Null can be returned if no transactions found.

Returns:

Date of the first transaction available.

getMaxDate

public Date getMaxDate(Date upperBoundary)

Get the date of the most recent transaction within the upper boundary. Override this method if you override getLedger(Date, Date) to bring entries from an external system.

Parameters:

upperBoundary - Upper boundary. If not null, the date returned should be less than this. Null can be returned if no transactions found.

Returns:

Most recent transaction date.

getLedger

public Ledger getLedger(Date from,
 Date to)

Get the ledger entries for the given period for the account. This method is invoked to obtain ledger entries from the system. You may override this method to return entries from external systems.

Parameters:

from - From date.

to - To date.

Returns:

Ledger.