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org.apache.myfaces.trinidad.model
Class CollectionModel

java.lang.Object
javax.faces.model.DataModel
org.apache.myfaces.trinidad.model.CollectionModel

All Implemented Interfaces:

LocalRowKeyIndex, RowKeyIndex

Direct Known Subclasses:

CollectionModelDecorator, SortableModel, TreeModel

public abstract class CollectionModel

extends javax.faces.model.DataModel

implements RowKeyIndex, LocalRowKeyIndex

The data model that is used by the Trinidad Table and Iterator components. This extends the Faces DataModel class and adds on support for rowKeys and sorting. Ordinary DataModels are still supported, and will automatically be wrapped into CollectionModels, but without the added functionality.

Row key support

In the Faces DataModel, rows are identified entirely by index. This causes major problems if the underlying data changes from one request to the next - a user request to delete one row may delete a different row because a row got added by another user, etc. To work around this, CollectionModel is based around row keys instead of indices. An implementation of CollectionModel must implement getRowKey() and setRowKey(), and handle conversion from integer indices to row keys. A trivial implementation might simply use Integer objects as the row keys, but a better version could use a unique ID in the row.

Nested Class Summary

Nested classes/interfaces inherited from interface org.apache.myfaces.trinidad.model.LocalRowKeyIndex

LocalRowKeyIndex.Confidence, LocalRowKeyIndex.LocalCachingStrategy

Constructor Summary

CollectionModel()

Method Summary

boolean	areRowsLocallyAvailable(int rowsToCheck) Check if a range of rows is locally available starting from current position.
boolean	areRowsLocallyAvailable(int startIndex, int rowsToCheck) Check if a range of rows is locally available starting from a row index.
boolean	areRowsLocallyAvailable(java.lang.Object startRowKey, int rowsToCheck) Check if a range of rows is locally available starting from a row key.
void	clearCachedRow(int index) Clears the row with the given index from local cache.
void	clearCachedRow(java.lang.Object rowKey) Clears the row with the given row key from local cache.
void	clearCachedRows(int startingIndex, int rowsToClear) Clears a range of rows from local cache starting from a row index.
void	clearCachedRows(java.lang.Object startingRowKey, int rowsToClear) Clears a range of rows from local cache starting from a row key This is a do nothing implemenation.
void	clearLocalCache() Clears the local cache.
void	ensureRowsAvailable(int rowCount) Ensure that the model has at least rowCount number of rows.
LocalRowKeyIndex.LocalCachingStrategy	getCachingStrategy() Returns the row caching strategy used by this implemenation.
int	getEstimatedRowCount() Convenient API to return a row count estimate.
LocalRowKeyIndex.Confidence	getEstimatedRowCountConfidence() Helper API to determine if the row count returned from getEstimatedRowCount() is EXACT, or an ESTIMATE.
java.lang.Object	getRowData(int rowIndex) Gets the rowData at the given index.
java.lang.Object	getRowData(java.lang.Object rowKey) Returns the rowData for the given rowKey without changing model currency.
abstract java.lang.Object	getRowKey() Gets the rowKey of the current row.
java.util.List<SortCriterion>	getSortCriteria() Gets the criteria that this collection is sorted by.
boolean	isRowAvailable(int rowIndex) Checks to see if the row at the given index is available.
boolean	isRowLocallyAvailable(int rowIndex) Given a row index, check if the row is locally available.
boolean	isRowLocallyAvailable(java.lang.Object rowKey) Given a row key, check if the row is locally available.
boolean	isSortable(java.lang.String property) Return true if this collection is sortable by the given property.
abstract void	setRowKey(java.lang.Object key) Finds the row with the matching key and makes it current
void	setSortCriteria(java.util.List<SortCriterion> criteria) Sorts this collection by the given criteria.

Methods inherited from class javax.faces.model.DataModel

addDataModelListener, getDataModelListeners, getRowCount, getRowData, getRowIndex, getWrappedData, isRowAvailable, removeDataModelListener, setRowIndex, setWrappedData

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.myfaces.trinidad.model.RowKeyIndex

getRowCount, getRowData, getRowIndex, isRowAvailable, setRowIndex

Constructor Detail

CollectionModel

public CollectionModel()

Method Detail

getRowKey

public abstract java.lang.Object getRowKey()

Gets the rowKey of the current row. rowKeys are safer to use than row indices because rowKeys are unaffected by mutations to this collection. rowKeys should have efficient implementations of Object.equals(java.lang.Object) and Object.hashCode() as they will be used as keys in hashtables. rowKeys should also be Serializable, so that the application can run under all JSF state-saving schemes.

Specified by:

getRowKey in interface RowKeyIndex

Returns:

this key should be Serializable and immutable.

See Also:

setRowKey(java.lang.Object)

setRowKey

public abstract void setRowKey(java.lang.Object key)

Finds the row with the matching key and makes it current

Specified by:

setRowKey in interface RowKeyIndex

Parameters:

key - the rowKey, previously obtained from getRowKey().

isRowAvailable

public boolean isRowAvailable(int rowIndex)

Checks to see if the row at the given index is available. This method makes the given row current and calls DataModel.isRowAvailable(). Finally, the row that was current before this method was called is made current again.

Specified by:

isRowAvailable in interface RowKeyIndex

Parameters:

rowIndex - the index of the row to check.

Returns:

true if data for the row exists.

See Also:

DataModel.isRowAvailable()

getRowData

public java.lang.Object getRowData(int rowIndex)

Gets the rowData at the given index. This method makes the given row current and calls DataModel.getRowData(). Finally, the row that was current before this method was called is made current again.

Specified by:

getRowData in interface RowKeyIndex

Parameters:

rowIndex - the index of the row to get data from.

Returns:

the data for the given row.

See Also:

DataModel.getRowData()

getRowData

public java.lang.Object getRowData(java.lang.Object rowKey)

Returns the rowData for the given rowKey without changing model currency. Implementations may choose to implement this behavior by saving and restoring the currency.

Parameters:

rowKey - the row key of the row to get data from.

Returns:

the data for the given row.

See Also:

DataModel.getRowData()

isSortable

public boolean isSortable(java.lang.String property)

Return true if this collection is sortable by the given property. This implementation always returns false;

getSortCriteria

public java.util.List<SortCriterion> getSortCriteria()

Gets the criteria that this collection is sorted by. This method should never return null. This implementation always returns an empty List.

Returns:

each element in this List is of type SortCriterion. An empty list is returned if this collection is not sorted.

See Also:

SortCriterion

setSortCriteria

public void setSortCriteria(java.util.List<SortCriterion> criteria)

Sorts this collection by the given criteria.

Parameters:

criteria - Each element in this List must be of type SortCriterion. The empty list may be used to cancel any sort order. null should be treated the same as an empty list.

See Also:

SortCriterion

areRowsLocallyAvailable

public boolean areRowsLocallyAvailable(int startIndex,
                                       int rowsToCheck)

Check if a range of rows is locally available starting from a row index.

Specified by:

areRowsLocallyAvailable in interface LocalRowKeyIndex

Parameters:

startIndex - starting row index to check

rowsToCheck - number of rows to check

Returns:

default implementation returns false

areRowsLocallyAvailable

public boolean areRowsLocallyAvailable(java.lang.Object startRowKey,
                                       int rowsToCheck)

Check if a range of rows is locally available starting from a row key.

Specified by:

areRowsLocallyAvailable in interface LocalRowKeyIndex

Parameters:

startRowKey - starting row key to check

rowsToCheck - number of rows to check

Returns:

default implementation returns false

areRowsLocallyAvailable

public boolean areRowsLocallyAvailable(int rowsToCheck)

Check if a range of rows is locally available starting from current position. This implementation checks for a valid current index and delegates to areRowsLocallyAvailable(startIndex, rowsToCheck)

Specified by:

areRowsLocallyAvailable in interface LocalRowKeyIndex

Parameters:

rowsToCheck - number of rows to check

Returns:

default implementation returns false

See Also:

areRowsLocallyAvailable(startIndex, rowsToCheck)

isRowLocallyAvailable

public boolean isRowLocallyAvailable(int rowIndex)

Given a row index, check if the row is locally available.

Specified by:

isRowLocallyAvailable in interface LocalRowKeyIndex

Parameters:

rowIndex - row index to check

Returns:

default implementation returns false

isRowLocallyAvailable

public boolean isRowLocallyAvailable(java.lang.Object rowKey)

Given a row key, check if the row is locally available.

Specified by:

isRowLocallyAvailable in interface LocalRowKeyIndex

Parameters:

rowKey - row key to check

Returns:

default implementation returns false

getEstimatedRowCount

public int getEstimatedRowCount()

Convenient API to return a row count estimate.

Specified by:

getEstimatedRowCount in interface LocalRowKeyIndex

Returns:

This implementation returns exact row count

See Also:

DataModel.getRowCount()

getEstimatedRowCountConfidence

public LocalRowKeyIndex.Confidence getEstimatedRowCountConfidence()

Helper API to determine if the row count returned from getEstimatedRowCount() is EXACT, or an ESTIMATE.

Specified by:

getEstimatedRowCountConfidence in interface LocalRowKeyIndex

Returns:

This implementation returns exact row count

See Also:

DataModel.getRowCount()

clearCachedRow

public void clearCachedRow(int index)

Clears the row with the given index from local cache. This is a do nothing implementaion�

Specified by:

clearCachedRow in interface LocalRowKeyIndex

Parameters:

index - row index for the row to remove from cache

See Also:

clearCachedRows(int, int)

clearCachedRow

public void clearCachedRow(java.lang.Object rowKey)

Clears the row with the given row key from local cache. This is a do nothing implementaion which delegates to the correcsponding range based api

Specified by:

clearCachedRow in interface LocalRowKeyIndex

Parameters:

rowKey - row key for the row to remove from cache

See Also:

clearCachedRows(Object, int)

clearCachedRows

public void clearCachedRows(int startingIndex,
                            int rowsToClear)

Clears a range of rows from local cache starting from a row index. This is a do nothing implemenation.

Specified by:

clearCachedRows in interface LocalRowKeyIndex

Parameters:

startingIndex - starting row index to clear the local cache from

rowsToClear - number of rows to clear

See Also:

clearLocalCache()

clearCachedRows

public void clearCachedRows(java.lang.Object startingRowKey,
                            int rowsToClear)

Clears a range of rows from local cache starting from a row key This is a do nothing implemenation.

Specified by:

clearCachedRows in interface LocalRowKeyIndex

Parameters:

startingRowKey - starting row key to clear the local cache from

rowsToClear - number of rows to clear

See Also:

clearLocalCache()

clearLocalCache

public void clearLocalCache()

Clears the local cache. This is a do nothing implementation

Specified by:

clearLocalCache in interface LocalRowKeyIndex

getCachingStrategy

public LocalRowKeyIndex.LocalCachingStrategy getCachingStrategy()

Returns the row caching strategy used by this implemenation. Default implementation indicates no caching supported

Specified by:

getCachingStrategy in interface LocalRowKeyIndex

Returns:

caching strategy none

See Also:

LocalRowKeyIndex.LocalCachingStrategy

ensureRowsAvailable

public void ensureRowsAvailable(int rowCount)

Ensure that the model has at least rowCount number of rows. This is especially useful for collection model that support paging. The default implementation is a no-op.

Parameters:

rowCount - the number of rows the model should hold.

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