net.sf.farrago.plugin
Class FarragoPluginCache

java.lang.Object
  org.eigenbase.util.CompoundClosableAllocation
      net.sf.farrago.util.FarragoCompoundAllocation
          net.sf.farrago.plugin.FarragoPluginCache

All Implemented Interfaces:

FarragoAllocation, FarragoAllocationOwner, ClosableAllocation, ClosableAllocationOwner

Direct Known Subclasses:

FarragoDataWrapperCache

public abstract class FarragoPluginCache
extends FarragoCompoundAllocation

FarragoPluginCache is an abstract private cache for loading instances of FarragoPlugin (and their component sub-objects). It requires an underlying shared FarragoObjectCache.

This class is only a partial implementation. For an example of how to build a full implementation, see FarragoDataWrapperCache.

Version:

$Id: //open/dev/farrago/src/net/sf/farrago/plugin/FarragoPluginCache.java#21 $

Author:

John V. Sichi

Field Summary

private FarragoPluginClassLoader	classLoader
private Map<String,Object>	mapMofIdToPlugin
private FarragoRepos	repos
private FarragoObjectCache	sharedCache

Fields inherited from class org.eigenbase.util.CompoundClosableAllocation

allocations

Constructor Summary

FarragoPluginCache(FarragoAllocationOwner owner, FarragoObjectCache sharedCache, FarragoPluginClassLoader classLoader, FarragoRepos repos)
Creates an empty cache.

Method Summary

protected Object	addToPrivateCache(FarragoObjectCache.Entry entry) Adds a plugin object to this cache.
Map<String,Object>	getMapMofIdToPlugin()
FarragoRepos	getRepos()
FarragoObjectCache	getSharedCache()
protected FarragoPlugin	initializePlugin(String libraryName, String jarAttributeName, Properties options) Initializes a plugin instance.
protected Object	searchPrivateCache(String mofId) Searches this cache for a plugin object identified by its catalog MofId.

Methods inherited from class org.eigenbase.util.CompoundClosableAllocation

addAllocation, closeAllocation, forgetAllocation, hasAllocations

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.eigenbase.util.ClosableAllocationOwner

addAllocation

Methods inherited from interface org.eigenbase.util.ClosableAllocation

closeAllocation

Methods inherited from interface org.eigenbase.util.ClosableAllocation

closeAllocation

Field Detail

mapMofIdToPlugin

private final Map<String,Object> mapMofIdToPlugin

sharedCache

private final FarragoObjectCache sharedCache

repos

private final FarragoRepos repos

classLoader

private final FarragoPluginClassLoader classLoader

Constructor Detail

FarragoPluginCache

public FarragoPluginCache(FarragoAllocationOwner owner,
                          FarragoObjectCache sharedCache,
                          FarragoPluginClassLoader classLoader,
                          FarragoRepos repos)

Creates an empty cache.

Parameters:

owner - FarragoAllocationOwner for this cache, to make sure everything gets discarded eventually

sharedCache - underlying shared cache

repos - FarragoRepos for wrapper initialization

Method Detail

getRepos

public FarragoRepos getRepos()

Returns:

the underlying repos

getSharedCache

public FarragoObjectCache getSharedCache()

Returns:

the underlying shared cache

getMapMofIdToPlugin

public Map<String,Object> getMapMofIdToPlugin()

Returns:

mapMofIdToPlugin

searchPrivateCache

protected Object searchPrivateCache(String mofId)

Searches this cache for a plugin object identified by its catalog MofId.

Parameters:

mofId - MofId of plugin object being loaded

Returns:

cached instance or null if not yet cached

addToPrivateCache

protected Object addToPrivateCache(FarragoObjectCache.Entry entry)

Adds a plugin object to this cache.

Parameters:

entry - pinned entry from underlying shared cache; key must be plugin object's catalog MofId

Returns:

cached plugin object

initializePlugin

protected FarragoPlugin initializePlugin(String libraryName,
                                         String jarAttributeName,
                                         Properties options)

Initializes a plugin instance.

Parameters:

libraryName - filename of jar containing plugin implementation

jarAttributeName - name of jar attribute to use to determine class name

options - options with which to initialize plugin

Returns:

initialized plugin