TDCacheable (Apache Derby V10.14 Internals)

java.lang.Object
- org.apache.derby.impl.sql.catalog.TDCacheable

All Implemented Interfaces:

Cacheable

Direct Known Subclasses:

NameTDCacheable, OIDTDCacheable
```
abstract class TDCacheable
extends java.lang.Object
implements Cacheable
```
This class implements a Cacheable for a DataDictionary cache of table descriptors. It is an abstract class - there is more than one cache of table descriptors per data dictionary, and this class provides the implementation that's common to all of them. The lookup key for the cache (the "identity" of the cache item) is provided by the subclass. Another design alternative was to make the table descriptors themselves the cacheable objects. This was rejected because: we would have only one way of caching table descriptors, and we need at least two (by UUID and by name); the contents of a table descriptor would have to be split out into a separate class, so it could be used as the createParameter to the createIdentity() method; the releasing of the Cacheable would have to be done when at the end of compilation by traversing the tree - by creating a separate Cacheable object, we can release the object within the getTableDescriptor() method after getting the table descriptor out of it.

Field Summary

Fields
Modifier and Type Field Description

protected DataDictionaryImpl dd

protected TableDescriptor td

Fields
Modifier and Type	Field	Description
`protected DataDictionaryImpl`	`dd`
`protected TableDescriptor`	`td`

Constructor Summary

Constructors
Constructor Description

TDCacheable(DataDictionaryImpl dd)

Constructors
Constructor	Description
`TDCacheable(DataDictionaryImpl dd)`

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`protected boolean`	`checkConsistency(TableDescriptor uncachedTD, java.lang.Object identity, HeaderPrintWriter reportInconsistent)`	Check the consistency of the table descriptor held by this TDCacheable versus an uncached table descriptor.
`void`	`clean(boolean forRemove)`	Clean the object.
`TableDescriptor`	`getTableDescriptor()`	Get the table descriptor that is associated with this Cacheable
`boolean`	`isDirty()`	Returns true of the object is dirty.

Methods inherited from interface org.apache.derby.iapi.services.cache.Cacheable
clearIdentity, createIdentity, getIdentity, setIdentity

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - td
```
protected TableDescriptor td
```
  - dd
```
protected final DataDictionaryImpl dd
```
- Constructor Detail
  - TDCacheable
```
TDCacheable(DataDictionaryImpl dd)
```
- Method Detail
  - 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 interface Cacheable
    
    See Also:
    
    Cacheable.clean(boolean)
  - 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 interface Cacheable
    
    See Also:
    
    Cacheable.isDirty()
  - getTableDescriptor
```
public TableDescriptor getTableDescriptor()
```
    Get the table descriptor that is associated with this Cacheable
  - checkConsistency
```
protected boolean checkConsistency(TableDescriptor uncachedTD,
                                   java.lang.Object identity,
                                   HeaderPrintWriter reportInconsistent)
                            throws StandardException
```
    Check the consistency of the table descriptor held by this TDCacheable versus an uncached table descriptor.
    
    Parameters:
    
    uncachedTD - The uncached descriptor to compare to
    
    identity - The identity of the table descriptor
    
    reportInconsistent - A HeaderPrintWriter to send complaints to
    
    Returns:
    
    true if the descriptors are the same, false if they're different
    
    Throws:
    
    StandardException - Thrown on error

Class TDCacheable

Field Summary

Constructor Summary

Method Summary

Methods inherited from interface org.apache.derby.iapi.services.cache.Cacheable

Methods inherited from class java.lang.Object

Field Detail

td

dd

Constructor Detail

TDCacheable

Method Detail

clean

isDirty

getTableDescriptor

checkConsistency