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java.lang.Object org.apache.lucene.store.Directory
public abstract class Directory
A Directory is a flat list of files. Files may be written once, when they are created. Once a file is created it may only be opened for read, or deleted. Random access is permitted both when reading and writing.
Java's i/o APIs not used directly, but rather all i/o is through this API. This permits things such as:
LockFactory
, and can be changed for each Directory
instance using setLockFactory(org.apache.lucene.store.LockFactory)
.
Nested Class Summary | |
---|---|
class |
Directory.IndexInputSlicer
Allows to create one or more sliced IndexInput instances from a single
file handle. |
Field Summary | |
---|---|
protected boolean |
isOpen
|
protected LockFactory |
lockFactory
Holds the LockFactory instance (implements locking for this Directory instance). |
Constructor Summary | |
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Directory()
|
Method Summary | |
---|---|
void |
clearLock(String name)
Attempt to clear (forcefully unlock and remove) the specified lock. |
abstract void |
close()
Closes the store. |
void |
copy(Directory to,
String src,
String dest,
IOContext context)
Copies the file src to Directory to under the new
file name dest. |
abstract IndexOutput |
createOutput(String name,
IOContext context)
Creates a new, empty file in the directory with the given name. |
Directory.IndexInputSlicer |
createSlicer(String name,
IOContext context)
Creates an Directory.IndexInputSlicer for the given file name. |
abstract void |
deleteFile(String name)
Removes an existing file in the directory. |
protected void |
ensureOpen()
|
abstract boolean |
fileExists(String name)
Returns true iff a file with the given name exists. |
abstract long |
fileLength(String name)
Returns the length of a file in the directory. |
LockFactory |
getLockFactory()
Get the LockFactory that this Directory instance is using for its locking implementation. |
String |
getLockID()
Return a string identifier that uniquely differentiates this Directory instance from other Directory instances. |
abstract String[] |
listAll()
Returns an array of strings, one for each file in the directory. |
Lock |
makeLock(String name)
Construct a Lock . |
abstract IndexInput |
openInput(String name,
IOContext context)
Returns a stream reading an existing file, with the specified read buffer size. |
void |
setLockFactory(LockFactory lockFactory)
Set the LockFactory that this Directory instance should use for its locking implementation. |
abstract void |
sync(Collection<String> names)
Ensure that any writes to these files are moved to stable storage. |
String |
toString()
|
Methods inherited from class java.lang.Object |
---|
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait |
Field Detail |
---|
protected volatile boolean isOpen
protected LockFactory lockFactory
Constructor Detail |
---|
public Directory()
Method Detail |
---|
public abstract String[] listAll() throws IOException
NoSuchDirectoryException
- if the directory is not prepared for any
write operations (such as createOutput(String, IOContext)
).
IOException
- in case of other IO errorspublic abstract boolean fileExists(String name) throws IOException
IOException
public abstract void deleteFile(String name) throws IOException
IOException
public abstract long fileLength(String name) throws IOException
FileNotFoundException
if the file does not exist
name
- the name of the file for which to return the length.
FileNotFoundException
- if the file does not exist.
IOException
- if there was an IO error while retrieving the file's
length.public abstract IndexOutput createOutput(String name, IOContext context) throws IOException
IOException
public abstract void sync(Collection<String> names) throws IOException
IOException
public abstract IndexInput openInput(String name, IOContext context) throws IOException
FSDirectory
and CompoundFileDirectory
.
IOException
public Lock makeLock(String name)
Lock
.
name
- the name of the lock filepublic void clearLock(String name) throws IOException
name
- name of the lock to be cleared.
IOException
public abstract void close() throws IOException
close
in interface Closeable
IOException
public void setLockFactory(LockFactory lockFactory) throws IOException
lockFactory
- instance of LockFactory
.
IOException
public LockFactory getLockFactory()
public String getLockID()
public String toString()
toString
in class Object
public void copy(Directory to, String src, String dest, IOContext context) throws IOException
Directory
to under the new
file name dest.
If you want to copy the entire source directory to the destination one, you can do so like this:
Directory to; // the directory to copy to for (String file : dir.listAll()) { dir.copy(to, file, newFile); // newFile can be either file, or a new name }
NOTE: this method does not check whether dest exist and will overwrite it if it does.
IOException
public Directory.IndexInputSlicer createSlicer(String name, IOContext context) throws IOException
Directory.IndexInputSlicer
for the given file name.
IndexInputSlicer allows other Directory
implementations to
efficiently open one or more sliced IndexInput
instances from a
single file handle. The underlying file handle is kept open until the
Directory.IndexInputSlicer
is closed.
IOException
- if an IOException
occursprotected final void ensureOpen() throws AlreadyClosedException
AlreadyClosedException
- if this Directory is closed
|
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