[jira] Updated: (TRINIDAD-1620) New APIs for Trinidad CollectionModel and TreeModel to better deal with large data sets

["Kamran Kashanian (JIRA)" <de...@myfaces.apache.org>]

     [ https://issues.apache.org/jira/browse/TRINIDAD-1620?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Kamran Kashanian updated TRINIDAD-1620:
---------------------------------------

    Status: Patch Available  (was: Open)

> New APIs for Trinidad CollectionModel and TreeModel to better deal with large data sets 
> ----------------------------------------------------------------------------------------
>
>                 Key: TRINIDAD-1620
>                 URL: https://issues.apache.org/jira/browse/TRINIDAD-1620
>             Project: MyFaces Trinidad
>          Issue Type: New Feature
>          Components: Components
>    Affects Versions:  1.2.12-core
>         Environment: All
>            Reporter: Kamran Kashanian
>
> Submitting a proposal for a new set of APIs for Trinidad CollectionModel and TreeModel.   The new APIs are intended  to enable a model user (usually the renderer) to better deal with large data sets (large models) and  provide the user more control over API calls that can cause a potentially expensive data fetch in the model.
> The issue with the existing CollectionModel APIs is that APIs such as setRowKey/setRowIndex/isRowAvailable can force the model to perform a data fetch. 
> For large models,   the renderer may need to optimize it's rendering and delay fetching data if a range of rows are not locally available. Also sometimes the client needs to convert row indices to a row keys (setRowIndex followed by getRowKey)  without forcing a potentially expensive data fetch.
> Proposing the following new APIs:
>   
> 1)  Add a new interface called LocalRowKeyIndex   (modeled after the existing org.apache.myfaces.trinidad.model.RowKeyIndex interface) which provides a set of local APIs.   The "local" APIs allow a client to query the model and determine if a  set of rows are locally available. "Locally available" can mean the  model has the given set of rows in a local cache and can honor a fetch request  efficiently (for example, without performing a SQL query).
> package org.apache.myfaces.trinidad.model;
> public interface LocalRowKeyIndex
> {
>   /**
>    * Given a row index, check if a row is locally available
>    * @param rowIndex index of row to check 
>    * @return true if row is locally available
>    */
>   public boolean isRowLocallyAvailable(int rowIndex);
>   /**
>    * Given a row key, check if a row is locally available
>    * @param rowKey row key for the row to check 
>    * @return true if row is locally available
>    */
>   public boolean isRowLocallyAvailable(Object rowKey);
>   /**
>    * Check if a range of rows is locally available starting from a row index
>    * @param startIndex staring index for the range  
>    * @param rowCount number of rows in the range
>    * @return true if range of rows is locally available
>    */
>   public boolean isRangeLocallyAvailable(int startIndex, int rowCount);
>   /**
>    * Check if a range of rows is locally available starting from a row key
>    * @param rowKey staring row key for the range  
>    * @param rowCount number of rows in the range
>    * @return true if range of rows is locally available
>    */
>   public boolean isRangeLocallyAvailable(Object rowKey, int rowCount);
>   
>   /**
>    * Convenient API to return a row count estimate.  This method can be optimized 
>    * to avoid a data fetch which may be required to return an exact row count
>    * @return estimated row count
>    */
>   public int getEstimatedRowCount();
>   /**
>    * Helper API to determine if the row count returned from {@link #getEstimatedRowCount} 
>    * is EXACT, or an ESTIMATE
>    */
>   public Confidence getEstimatedRowCountConfidence();
>   
>   /**
>    * Enum used in the {@link #getEstimatedRowCountConfidence} API to determine 
>    * if the row count is exact or an estimate
>    */
>   public enum Confidence
>   {
>     /**
>      * The row count returned by {@link #getEstimatedRowCount} is exact
>      */
>     EXACT,
>     /**
>      * The row count returned by {@link #getEstimatedRowCount} is an estimate
>      */
>     ESTIMATE
>   }  
> }
> 2) Enhance the APIs in the existing org.apache.myfaces.trinidad.model.RowKeyIndex interface to add support for:
> a) Row key  - based APIs so the client does not have to perform row key to row index conversion (and potentially cause unnecessary data fetch)
> b) Provide new APIs to enable the client to check for availability of a range of rows without having to loop over the rows and call the existing isRowAvailable API.
> Add the following methods to the existing org.apache.myfaces.trinidad.model.RowKeyIndex interface:
>   /**
>    * Check for an available row by row key. 
>    * @param rowKey the row key for the row to check.
>    * @return true if a value exists; false otherwise.
>    */
>   public boolean isRowAvailable(Object rowKey);
>   /**
>    * Get row data by row key. 
>    * @param rowKey the row key for the row to get data.
>    * @return row data
>    */
>   public Object getRowData(Object rowKey); 
>   /**
>    * Check if a range of rows is available starting from the current position 
>    * @param rowCount number of rows to check
>    * @return true if all rows in range are available
>    */
>   public boolean isRangeAvailable(int rowCount);
>   /**
>    * Check if a range of rows is available from a starting index without 
>    * requiring the client to iterate over the rows
>    * @param startIndex the starting index for the range
>    * @param rowCount number of rows to check
>    * @return true if all rows in range are available
>    */
>   public boolean isRangeAvailable(int startIndex, int rowCount) ;
>   /**
>    * Check if a range of rows is available from a starting row key without 
>    * requiring the client to iterate over the rows
>    * @param rowKey the starting row key for the range
>    * @param rowCount number of rows to check
>    * @return true if all rows in range are available
>    */
>   public boolean isRangeAvailable(Object rowKey, int rowCount) ;  
> 3) Provide local APIs in org.apache.myfaces.trinidad.model.TreeModel  for example to check if data for a child collection is locally available:
>   /**
>    * Indicates whether data for a child model (children of the current node) is 
>    * locally available. Locally available means no data fetch is required 
>    * as a result of a call to  {@link #enterContainer}. The default 
>    * implementation returns true if the current node is a container.  
>    * Override to optimize for the case where child data is not locally available
>    * @return true if child data is locally available
>    */
>   public boolean isChildCollectionLocallyAvailable()
>   {
>     return isContainer();
>   }
>   /**
>    * Indicates whether child data for the node with the given index is
>    * locally available.   This method first checks to see if the parent node
>    * at the given index is locally available by calling {@link #isRowLocallyAvailable(int}.
>    * If the parent node is locally available, this method moves the model to the
>    * parent node and calls {@link #isChildCollectionLocallyAvailable()}
>    * The current row does not change after this call
>    * @param index
>    * @return true if child data is available, false otherwise
>    */
>   public boolean isChildCollectionLocallyAvailable(int index)
>   {
>     if (isRowLocallyAvailable(index))
>     {
>       int oldIndex = getRowIndex();
>       try
>       {
>         setRowIndex(index);
>         return isChildCollectionLocallyAvailable();
>       }
>       finally
>       {
>         setRowIndex(oldIndex);
>       }
>     }
>     else
>     {
>       return false;
>     }
>   }
>   /**
>    * Indicates whether child data for the node with the given row key is
>    * locally available.   This method first checks to see if the parent node
>    * with the given row key is locally available by calling {@link #isRowLocallyAvailable(Object)}.
>    * If the parent node is locally available, this method moves the model to the
>    * parent node and calls {@link #isChildCollectionLocallyAvailable()}
>    * The current row does not change after this call
>    * @param rowKey
>    * @return true if child data is available, false otherwise
>    */
>   public boolean isChildCollectionLocallyAvailable(Object rowKey)
>   {
>     if (isRowLocallyAvailable(rowKey))
>     {
>       Object oldKey = getRowKey();
>       try
>       {
>         setRowKey(rowKey);
>         return isChildCollectionLocallyAvailable();
>       }
>       finally
>       {
>         setRowKey(oldKey);
>       }
>     }
>     else
>     {
>       return false;
>     }
>   }
> The following changes will be required to support the above APIs:
> 1) Add the new LocalRowKeyIndex interface to the org.apache.myfaces.trinidad.model. package
> 2)  org.apache.myfaces.trinidad.model.CollectionModel will implement the new LocalRowKeyIndex interface and will provide default implementation for the local APIs.  The default implementation of local APIs will just call the existing non-local APIs
> 3) UIXIterator and UIXHierarchy will implement the new LocalRowKeyIndex interface and provide the component level implementations for the local APIs.  The component level implementations just delegate to the model
> 4) Provide trivial implementation for the new APIs in org.apache.myfaces.trinidad.model.CollectionModelDecorator

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