com.vaadin.client.data
Class CacheStrategy.AbstractBasicSymmetricalCacheStrategy

java.lang.Object
  com.vaadin.client.data.CacheStrategy.AbstractBasicSymmetricalCacheStrategy

All Implemented Interfaces:

CacheStrategy

Direct Known Subclasses:

CacheStrategy.DefaultCacheStrategy

Enclosing interface:

CacheStrategy

public abstract static class CacheStrategy.AbstractBasicSymmetricalCacheStrategy
extends java.lang.Object
implements CacheStrategy

A helper class for creating a simple symmetric cache strategy that uses the same logic for both rows before and after the currently cached range.

This simple approach rules out more advanced heuristics that would take the current scrolling direction or past scrolling behavior into account.

Nested Class Summary

Nested classes/interfaces inherited from interface com.vaadin.client.data.CacheStrategy

CacheStrategy.AbstractBasicSymmetricalCacheStrategy, CacheStrategy.DefaultCacheStrategy

Constructor Summary

CacheStrategy.AbstractBasicSymmetricalCacheStrategy()

Method Summary

com.vaadin.shared.ui.grid.Range	getMaxCacheRange(com.vaadin.shared.ui.grid.Range displayedRange, com.vaadin.shared.ui.grid.Range cachedRange, com.vaadin.shared.ui.grid.Range estimatedAvailableRange) Gets the maximum row range that should be cached.
abstract int	getMaximumCacheSize(int pageSize) Gets the maximum number of extra items to cache in one direction.
com.vaadin.shared.ui.grid.Range	getMinCacheRange(com.vaadin.shared.ui.grid.Range displayedRange, com.vaadin.shared.ui.grid.Range cachedRange, com.vaadin.shared.ui.grid.Range estimatedAvailableRange) Gets the minimum row range that should be cached.
abstract int	getMinimumCacheSize(int pageSize) Gets the the minimum number of extra items to cache in one direction.
void	onDataArrive(double roundTripTime, int rowCount) Called whenever data requested by the data source has arrived.

Methods inherited from class java.lang.Object

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

Constructor Detail

CacheStrategy.AbstractBasicSymmetricalCacheStrategy

public CacheStrategy.AbstractBasicSymmetricalCacheStrategy()

Method Detail

onDataArrive

public void onDataArrive(double roundTripTime,
                         int rowCount)

Description copied from interface: CacheStrategy

Called whenever data requested by the data source has arrived. This information can e.g. be used for measuring how long it takes to fetch different number of rows from the server.

A cache strategy implementation cannot use this information to keep track of which items are in the cache since the data source might discard items without notifying the cache strategy.

Specified by:

onDataArrive in interface CacheStrategy

Parameters:

roundTripTime - the total number of milliseconds elapsed from requesting the data until the response was passed to the data source

rowCount - the number of received rows

getMinCacheRange

public com.vaadin.shared.ui.grid.Range getMinCacheRange(com.vaadin.shared.ui.grid.Range displayedRange,
                                                        com.vaadin.shared.ui.grid.Range cachedRange,
                                                        com.vaadin.shared.ui.grid.Range estimatedAvailableRange)

Description copied from interface: CacheStrategy

Gets the minimum row range that should be cached. The data source will fetch new data if the currently cached range does not fill the entire minimum cache range.

Specified by:

getMinCacheRange in interface CacheStrategy

Parameters:

displayedRange - the range of currently displayed rows

cachedRange - the range of currently cached rows

estimatedAvailableRange - the estimated range of rows available for the data source

Returns:

the minimum range of rows that should be cached, should at least include the displayed range and should not exceed the total estimated available range

getMaxCacheRange

public com.vaadin.shared.ui.grid.Range getMaxCacheRange(com.vaadin.shared.ui.grid.Range displayedRange,
                                                        com.vaadin.shared.ui.grid.Range cachedRange,
                                                        com.vaadin.shared.ui.grid.Range estimatedAvailableRange)

Description copied from interface: CacheStrategy

Gets the maximum row range that should be cached. The data source will discard cached rows that are outside the maximum range.

Specified by:

getMaxCacheRange in interface CacheStrategy

Parameters:

displayedRange - the range of currently displayed rows

cachedRange - the range of currently cached rows

estimatedAvailableRange - the estimated range of rows available for the data source

Returns:

the maximum range of rows that should be cached, should at least include the displayed range and should not exceed the total estimated available range

getMaximumCacheSize

public abstract int getMaximumCacheSize(int pageSize)

Gets the maximum number of extra items to cache in one direction.

Parameters:

pageSize - the current number of items used at once

Returns:

maximum of items to cache

getMinimumCacheSize

public abstract int getMinimumCacheSize(int pageSize)

Gets the the minimum number of extra items to cache in one direction.

Parameters:

pageSize - the current number of items used at once

Returns:

minimum number of items to cache