org.apache.lucene.store
Class RateLimitedDirectoryWrapper

java.lang.Object
  org.apache.lucene.store.Directory
      org.apache.lucene.store.RateLimitedDirectoryWrapper

All Implemented Interfaces:

Closeable

public final class RateLimitedDirectoryWrapper
extends Directory

A Directory wrapper that allows IndexOutput rate limiting using IO context specific rate limiters.

See Also:

setRateLimiter(RateLimiter, IOContext.Context)

WARNING: This API is experimental and might change in incompatible ways in the next release.

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.lucene.store.Directory

Directory.IndexInputSlicer

Field Summary

Fields inherited from class org.apache.lucene.store.Directory

isOpen, lockFactory

Constructor Summary

RateLimitedDirectoryWrapper(Directory wrapped)

Method Summary

void	clearLock(String name) Attempt to clear (forcefully unlock and remove) the specified lock.
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.
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.
void	deleteFile(String name) Removes an existing file in the directory.
boolean	fileExists(String name) Returns true iff a file with the given name exists.
long	fileLength(String name) Returns the length of a file in the directory.
Directory	getDelegate()
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.
Double	getMaxWriteMBPerSec(IOContext.Context context) See setMaxWriteMBPerSec(java.lang.Double, org.apache.lucene.store.IOContext.Context).
String[]	listAll() Returns an array of strings, one for each file in the directory.
Lock	makeLock(String name) Construct a Lock.
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.
void	setMaxWriteMBPerSec(Double mbPerSec, IOContext.Context context) Sets the maximum (approx) MB/sec allowed by all write IO performed by IndexOutput created with the given IOContext.Context.
void	setRateLimiter(RateLimiter mergeWriteRateLimiter, IOContext.Context context) Sets the rate limiter to be used to limit (approx) MB/sec allowed by all IO performed with the given context.
void	sync(Collection<String> names) Ensure that any writes to these files are moved to stable storage.
String	toString()

Methods inherited from class org.apache.lucene.store.Directory

ensureOpen

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

RateLimitedDirectoryWrapper

public RateLimitedDirectoryWrapper(Directory wrapped)

Method Detail

getDelegate

public Directory getDelegate()

listAll

public String[] listAll()
                 throws IOException

Description copied from class: Directory

Returns an array of strings, one for each file in the directory.

Specified by:

listAll in class Directory

Throws:

NoSuchDirectoryException - if the directory is not prepared for any write operations (such as Directory.createOutput(String, IOContext)).

IOException - in case of other IO errors

fileExists

public boolean fileExists(String name)
                   throws IOException

Description copied from class: Directory

Returns true iff a file with the given name exists.

Specified by:

fileExists in class Directory

Throws:

IOException

deleteFile

public void deleteFile(String name)
                throws IOException

Description copied from class: Directory

Removes an existing file in the directory.

Specified by:

deleteFile in class Directory

Throws:

IOException

fileLength

public long fileLength(String name)
                throws IOException

Description copied from class: Directory

Returns the length of a file in the directory. This method follows the following contract:

• Throws FileNotFoundException if the file does not exist
• Returns a value ≥0 if the file exists, which specifies its length.

Specified by:

fileLength in class Directory

Parameters:

name - the name of the file for which to return the length.

Throws:

FileNotFoundException - if the file does not exist.

IOException - if there was an IO error while retrieving the file's length.

createOutput

public IndexOutput createOutput(String name,
                                IOContext context)
                         throws IOException

Description copied from class: Directory

Creates a new, empty file in the directory with the given name. Returns a stream writing this file.

Specified by:

createOutput in class Directory

Throws:

IOException

sync

public void sync(Collection<String> names)
          throws IOException

Description copied from class: Directory

Ensure that any writes to these files are moved to stable storage. Lucene uses this to properly commit changes to the index, to prevent a machine/OS crash from corrupting the index.

NOTE: Clients may call this method for same files over and over again, so some impls might optimize for that. For other impls the operation can be a noop, for various reasons.

Specified by:

sync in class Directory

Throws:

IOException

openInput

public IndexInput openInput(String name,
                            IOContext context)
                     throws IOException

Description copied from class: Directory

Returns a stream reading an existing file, with the specified read buffer size. The particular Directory implementation may ignore the buffer size. Currently the only Directory implementations that respect this parameter are FSDirectory and CompoundFileDirectory.

Specified by:

openInput in class Directory

Throws:

IOException

close

public void close()
           throws IOException

Description copied from class: Directory

Closes the store.

Specified by:

close in interface Closeable

Specified by:

close in class Directory

Throws:

IOException

createSlicer

public Directory.IndexInputSlicer createSlicer(String name,
                                               IOContext context)
                                        throws IOException

Description copied from class: Directory

Creates an 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.

Overrides:

createSlicer in class Directory

Throws:

IOException - if an IOException occurs

makeLock

public Lock makeLock(String name)

Description copied from class: Directory

Construct a Lock.

Overrides:

makeLock in class Directory

Parameters:

name - the name of the lock file

clearLock

public void clearLock(String name)
               throws IOException

Description copied from class: Directory

Attempt to clear (forcefully unlock and remove) the specified lock. Only call this at a time when you are certain this lock is no longer in use.

Overrides:

clearLock in class Directory

Parameters:

name - name of the lock to be cleared.

Throws:

IOException

setLockFactory

public void setLockFactory(LockFactory lockFactory)
                    throws IOException

Description copied from class: Directory

Set the LockFactory that this Directory instance should use for its locking implementation. Each * instance of LockFactory should only be used for one directory (ie, do not share a single instance across multiple Directories).

Overrides:

setLockFactory in class Directory

Parameters:

lockFactory - instance of LockFactory.

Throws:

IOException

getLockFactory

public LockFactory getLockFactory()

Description copied from class: Directory

Get the LockFactory that this Directory instance is using for its locking implementation. Note that this may be null for Directory implementations that provide their own locking implementation.

Overrides:

getLockFactory in class Directory

getLockID

public String getLockID()

Description copied from class: Directory

Return a string identifier that uniquely differentiates this Directory instance from other Directory instances. This ID should be the same if two Directory instances (even in different JVMs and/or on different machines) are considered "the same index". This is how locking "scopes" to the right index.

Overrides:

getLockID in class Directory

toString

public String toString()

Overrides:

toString in class Directory

copy

public void copy(Directory to,
                 String src,
                 String dest,
                 IOContext context)
          throws IOException

Description copied from class: Directory

Copies the file src to 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.

Overrides:

copy in class Directory

Throws:

IOException

setMaxWriteMBPerSec

public void setMaxWriteMBPerSec(Double mbPerSec,
                                IOContext.Context context)

Sets the maximum (approx) MB/sec allowed by all write IO performed by IndexOutput created with the given IOContext.Context. Pass null to have no limit.

NOTE: For already created IndexOutput instances there is no guarantee this new rate will apply to them; it will only be guaranteed to apply for new created IndexOutput instances.

NOTE: this is an optional operation and might not be respected by all Directory implementations. Currently only buffered Directory implementations use rate-limiting.

Throws:

IllegalArgumentException - if context is null

AlreadyClosedException - if the Directory is already closed

WARNING: This API is experimental and might change in incompatible ways in the next release.

setRateLimiter

public void setRateLimiter(RateLimiter mergeWriteRateLimiter,
                           IOContext.Context context)

Sets the rate limiter to be used to limit (approx) MB/sec allowed by all IO performed with the given context. Pass null to have no limit.

Passing an instance of rate limiter compared to setting it using setMaxWriteMBPerSec(Double, IOContext.Context) allows to use the same limiter instance across several directories globally limiting IO across them.

Throws:

IllegalArgumentException - if context is null

AlreadyClosedException - if the Directory is already closed

WARNING: This API is experimental and might change in incompatible ways in the next release.

getMaxWriteMBPerSec

public Double getMaxWriteMBPerSec(IOContext.Context context)

See setMaxWriteMBPerSec(java.lang.Double, org.apache.lucene.store.IOContext.Context).

Throws:

IllegalArgumentException - if context is null

AlreadyClosedException - if the Directory is already closed

WARNING: This API is experimental and might change in incompatible ways in the next release.