Class SPSNameCacheable
- java.lang.Object
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- org.apache.derby.impl.sql.catalog.SPSNameCacheable
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- All Implemented Interfaces:
Cacheable
class SPSNameCacheable extends java.lang.Object implements Cacheable
This class implements a Cacheable for a DataDictionary cache of sps descriptors, with the lookup key being the name/schema of the sps. Assumes client passes in a string that includes the schema name.The cache ensures that the class of the target sps is loaded if the sps is found in cache. This is ensured by calling loadGeneratedClass() on the sps when it is added to the cache. Each subsequent user of the sps cache will do its own load/unload on the class. Because the class manager/loader maintains reference counts on the classes it is handling, the user load/unload will just increment/decrement the use count. Only when the sps is uncached will it be unloaded.
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Field Summary
Fields Modifier and Type Field Description private DataDictionaryImpl
dd
private TableKey
identity
private SPSDescriptor
spsd
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Constructor Summary
Constructors Constructor Description SPSNameCacheable(DataDictionaryImpl dd)
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description void
clean(boolean forRemove)
Clean the object.void
clearIdentity()
Put the object into the No Identity state.Cacheable
createIdentity(java.lang.Object key, java.lang.Object createParameter)
Create a new item.java.lang.Object
getIdentity()
Get the identity of this object.SPSDescriptor
getSPSDescriptor()
Get the sps descriptor that is associated with this Cacheableboolean
isDirty()
Returns true of the object is dirty.Cacheable
setIdentity(java.lang.Object key)
Set the identity of the object.
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Field Detail
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identity
private TableKey identity
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spsd
private SPSDescriptor spsd
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dd
private final DataDictionaryImpl dd
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Constructor Detail
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SPSNameCacheable
SPSNameCacheable(DataDictionaryImpl dd)
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Method Detail
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clearIdentity
public void clearIdentity()
Description copied from interface:Cacheable
Put the object into the No Identity state.
MT - single thread required - Method must only be called be cache manager and the cache manager will guarantee only one thread can be calling it.- Specified by:
clearIdentity
in interfaceCacheable
- See Also:
Cacheable.clearIdentity()
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getIdentity
public java.lang.Object getIdentity()
Description copied from interface:Cacheable
Get the identity of this object.
MT - thread safe.- Specified by:
getIdentity
in interfaceCacheable
- See Also:
Cacheable.getIdentity()
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createIdentity
public Cacheable createIdentity(java.lang.Object key, java.lang.Object createParameter)
Description copied from interface:Cacheable
Create a new item.Create a new item and set the identity of the object to represent it. The object will be in the No Identity state, ie. it will have just been created or clearIdentity() was just called.
The object must copy the information out of key, not just store a reference to key if the key is not immutable. After this call the expression getIdentity().equals(key) must return true.
If the class of the object needs to change (e.g. to support a different format) then the object should create a new object, call its initParameter() with the parameters the original object was called with, set its identity and return a reference to it. The cache manager will discard the reference to the old object.
If an exception is thrown the object must be left in the no-identity state.
MT - single thread required - Method must only be called be cache manager and the cache manager will guarantee only one thread can be calling it.- Specified by:
createIdentity
in interfaceCacheable
- Returns:
- an object reference if the object can take on the identity, null otherwise.
- See Also:
Cacheable.createIdentity(java.lang.Object, java.lang.Object)
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setIdentity
public Cacheable setIdentity(java.lang.Object key) throws StandardException
Description copied from interface:Cacheable
Set the identity of the object.Set the identity of the object to represent an item that already exists, e.g. an existing container. The object will be in the No Identity state, ie. it will have just been created or clearIdentity() was just called.
The object must copy the information out of key, not just store a reference to key. After this call the expression getIdentity().equals(key) must return true.
If the class of the object needs to change (e.g. to support a different format) then the object should create a new object, call its initParameter() with the parameters the original object was called with, set its identity and return a reference to it. The cache manager will discard the reference to the old object.
If an exception is thrown the object must be left in the no-identity state.
MT - single thread required - Method must only be called be cache manager and the cache manager will guarantee only one thread can be calling it.- Specified by:
setIdentity
in interfaceCacheable
- Returns:
- an object reference if the object can take on the identity, null otherwise.
- Throws:
StandardException
- Thrown on error- See Also:
Cacheable.setIdentity(java.lang.Object)
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clean
public void clean(boolean forRemove)
Description copied from interface:Cacheable
Clean the object. It is up to the object to ensure synchronization of the isDirty() and clean() method calls.
If forRemove is true then the object is being removed due to an explict remove request, in this case the cache manager will have called this method regardless of the state of the isDirty()
If an exception is thrown the object must be left in the clean state.
MT - thread safe - Can be called at any time by the cache manager, it is the responsibility of the object implementing Cacheable to ensure any users of the object do not conflict with the clean call.- Specified by:
clean
in interfaceCacheable
- See Also:
Cacheable.clean(boolean)
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isDirty
public boolean isDirty()
Description copied from interface:Cacheable
Returns true of the object is dirty. May be called when the object is kept or unkept.
MT - thread safe- Specified by:
isDirty
in interfaceCacheable
- See Also:
Cacheable.isDirty()
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getSPSDescriptor
public SPSDescriptor getSPSDescriptor()
Get the sps descriptor that is associated with this Cacheable
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