Class BaseDirCacheEditor
- Direct Known Subclasses:
DirCacheBuilder
,DirCacheEditor
DirCache
.
The different update strategies extend this class to provide their own unique services to applications.
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Field Summary
Fields -
Constructor Summary
ConstructorsModifierConstructorDescriptionprotected
BaseDirCacheEditor
(DirCache dc, int ecnt) Construct a new editor. -
Method Summary
Modifier and TypeMethodDescriptionprivate void
boolean
commit()
Finish, write, commit this change, and release the index lock.protected void
fastAdd
(DirCacheEntry newEntry) Append one entry into the resulting entry list.protected void
fastKeep
(int pos, int cnt) Add a range of existing entries from the destination cache.abstract void
finish()
Finish this builder and update the destinationDirCache
.Get theDirCache
private static int
lastSlash
(byte[] path) private static int
nextSlash
(byte[] b, int p) protected void
replace()
Update the DirCache with the contents ofentries
.private static boolean
startsWith
(byte[] a, byte[] b, int n)
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Field Details
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cache
The cache instance this editor updates duringfinish()
. -
entries
Entry table this builder will eventually replace intocache
.Use
fastAdd(DirCacheEntry)
orfastKeep(int, int)
to make additions to this table. The table is automatically expanded if it is too small for a new addition.Typically the entries in here are sorted by their path names, just like they are in the DirCache instance.
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entryCnt
protected int entryCntTotal number of valid entries inentries
.
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Constructor Details
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BaseDirCacheEditor
Construct a new editor.- Parameters:
dc
- the cache this editor will eventually update.ecnt
- estimated number of entries the editor will have upon completion. This sizes the initial entry table.
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Method Details
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getDirCache
Get theDirCache
- Returns:
- the cache we will update on
finish()
.
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fastAdd
Append one entry into the resulting entry list.The entry is placed at the end of the entry list. The caller is responsible for making sure the final table is correctly sorted.
The
entries
table is automatically expanded if there is insufficient space for the new addition.- Parameters:
newEntry
- the new entry to add.
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fastKeep
protected void fastKeep(int pos, int cnt) Add a range of existing entries from the destination cache.The entries are placed at the end of the entry list, preserving their current order. The caller is responsible for making sure the final table is correctly sorted.
This method copies from the destination cache, which has not yet been updated with this editor's new table. So all offsets into the destination cache are not affected by any updates that may be currently taking place in this editor.
The
entries
table is automatically expanded if there is insufficient space for the new additions.- Parameters:
pos
- first entry to copy from the destination cache.cnt
- number of entries to copy.
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finish
public abstract void finish()Finish this builder and update the destinationDirCache
.When this method completes this builder instance is no longer usable by the calling application. A new builder must be created to make additional changes to the index entries.
After completion the DirCache returned by
getDirCache()
will contain all modifications.Note to implementors: Make sure
entries
is fully sorted then invokereplace()
to update the DirCache with the new table. -
replace
protected void replace() -
checkNameConflicts
private void checkNameConflicts() -
lastSlash
private static int lastSlash(byte[] path) -
nextSlash
private static int nextSlash(byte[] b, int p) -
startsWith
private static boolean startsWith(byte[] a, byte[] b, int n) -
commit
Finish, write, commit this change, and release the index lock.If this method fails (returns false) the lock is still released.
This is a utility method for applications as the finish-write-commit pattern is very common after using a builder to update entries.
- Returns:
- true if the commit was successful and the file contains the new data; false if the commit failed and the file remains with the old data.
- Throws:
IllegalStateException
- the lock is not held.IOException
- the output file could not be created. The caller no longer holds the lock.
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