DirCache
by supplying discrete
edit commands.
An editor updates a DirCache by taking a list of
DirCacheEditor.PathEdit
commands and
executing them against the entries of the destination cache to produce a new
cache. This edit style allows applications to insert a few commands and then
have the editor compute the proper entry indexes necessary to perform an
efficient in-order update of the index records. This can be easier to use
than DirCacheBuilder
.
- See Also:
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Nested Class Summary
Nested ClassesModifier and TypeClassDescriptionstatic final class
Deletes a single file entry from the index.static final class
Recursively deletes all paths under a subtree.static class
Any index record update. -
Field Summary
FieldsModifier and TypeFieldDescriptionprotected DirCache
protected DirCacheEntry[]
protected int
Total number of valid entries inBaseDirCacheEditor.entries
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Constructor Summary
ConstructorsModifierConstructorDescriptionprotected
DirCacheEditor
(DirCache dc, int ecnt) Construct a new editor. -
Method Summary
Modifier and TypeMethodDescriptionvoid
add
(DirCacheEditor.PathEdit edit) Append one edit command to the list of commands to be applied.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.void
finish()
Finish this builder and update the destinationDirCache
.Get theDirCache
protected void
replace()
Update the DirCache with the contents ofBaseDirCacheEditor.entries
.
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Field Details
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cache
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entries
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entryCnt
protected int entryCntTotal number of valid entries inBaseDirCacheEditor.entries
.
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Constructor Details
-
DirCacheEditor
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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add
Append one edit command to the list of commands to be applied.Edit commands may be added in any order chosen by the application. They are automatically rearranged by the builder to provide the most efficient update possible.
- Parameters:
edit
- another edit command.
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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:
IOException
- the output file could not be created. The caller no longer holds the lock.
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finish
public 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. -
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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replace
protected void replace()
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