jetbrains.exodus.entitystore

Class BlobVault

java.lang.Object

jetbrains.exodus.entitystore.BlobVault

All Implemented Interfaces:

Backupable, BlobHandleGenerator

public abstract class BlobVault
extends java.lang.Object
implements BlobHandleGenerator, Backupable

BlobVault is base class describing interface to binary large objects (BLOBs) used internally by implementation of PersistentEntityStore.

Blob values are identified by blob handles generated by BlobHandleGenerator. PersistentEntityStore encapsulates mapping of Entity blob values to blob handles, whereas BlobVault allows to read/write blob values identified by blob handles. Blob values are immutable, i.e. blob value by a blob handle cannot be changed, only deleted.

BlobVault allows to get string content of blob for method Entity.getBlobString(String). In order to reduce CPU consumption on transformation of binary content to UTF-8 strings, BlobVault encapsulates a cache of blob strings.

See Also:

PersistentEntityStore, BlobHandleGenerator

Field Summary

Fields

Modifier and Type	Field and Description
protected static org.slf4j.Logger	logger

Fields inherited from interface jetbrains.exodus.entitystore.BlobHandleGenerator

IMMUTABLE

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	BlobVault(@NotNull BlobVault source)
protected	BlobVault(@NotNull PersistentEntityStoreConfig config)

Method Summary

Modifier and Type	Method and Description
abstract void	clear() Is called on PersistentEntityStore.clear().
jetbrains.exodus.util.ByteArraySizedInputStream	cloneFile(@NotNull java.io.File file)
jetbrains.exodus.util.ByteArraySizedInputStream	cloneStream(@NotNull java.io.InputStream source, boolean closeSource)
abstract void	close() Is called on EntityStore.close().
java.io.ByteArrayOutputStream	copyStream(@NotNull java.io.InputStream source, boolean closeSource)
abstract boolean	delete(long blobHandle)
abstract void	flushBlobs(@Nullable jetbrains.exodus.core.dataStructures.hash.LongHashMap<java.io.InputStream> blobStreams, @Nullable jetbrains.exodus.core.dataStructures.hash.LongHashMap<java.io.File> blobFiles, @Nullable jetbrains.exodus.core.dataStructures.hash.LongSet deferredBlobsToDelete, @NotNull Transaction txn) Method called by PersistentEntityStore to flush blobs identified by blobs.
abstract @NotNull BlobVaultItem	getBlob(long blobHandle)
java.lang.String	getBlobKey(long blobHandle)
@NotNull java.io.File	getBlobLocation(long blobHandle)
abstract @Nullable java.io.InputStream	getContent(long blobHandle, @NotNull Transaction txn) Returns binary content of blob identified by specified blob handle as InputStream.
int	getIdentity()
abstract long	getSize(long blobHandle, @NotNull Transaction txn) Returns size of blob identified by specified blob handle in bytes.
BlobVault	getSourceVault()
@Nullable java.lang.String	getStringContent(long blobHandle, @NotNull Transaction txn) Returns string content of blob identified by specified blob handle.
float	getStringContentCacheHitRate()
abstract boolean	requiresTxn() Returns true if BlobVault implementation requires transaction to flush blobs when StoreTransaction.flush() or StoreTransaction.commit() is called.
abstract long	size() Returns amount of disk space occupied by the BlobVault.

Methods inherited from class java.lang.Object

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

Methods inherited from interface jetbrains.exodus.entitystore.BlobHandleGenerator

nextHandle

Methods inherited from interface jetbrains.exodus.backup.Backupable

getBackupStrategy

Field Detail

logger

protected static final org.slf4j.Logger logger

Constructor Detail

BlobVault

protected BlobVault(@NotNull
                    @NotNull BlobVault source)

BlobVault

protected BlobVault(@NotNull
                    @NotNull PersistentEntityStoreConfig config)

Method Detail

getSourceVault

public BlobVault getSourceVault()

getIdentity

public int getIdentity()

getBlobLocation

@NotNull
public @NotNull java.io.File getBlobLocation(long blobHandle)

getBlobKey

public java.lang.String getBlobKey(long blobHandle)

getBlob

@NotNull
public abstract @NotNull BlobVaultItem getBlob(long blobHandle)

delete

public abstract boolean delete(long blobHandle)

getContent

@Nullable
public abstract @Nullable java.io.InputStream getContent(long blobHandle,
                                                                    @NotNull
                                                                    @NotNull Transaction txn)

Returns binary content of blob identified by specified blob handle as InputStream.

Parameters:

blobHandle - blob handle

txn - Transaction instance

Returns:

binary content of blob as InputStream

See Also:

Entity.getBlob(String)

getSize

public abstract long getSize(long blobHandle,
                             @NotNull
                             @NotNull Transaction txn)

Returns size of blob identified by specified blob handle in bytes.

Parameters:

blobHandle - blob handle

txn - Transaction instance

Returns:

size of blob in bytes

See Also:

Entity.getBlobSize(String)

requiresTxn

public abstract boolean requiresTxn()

Returns true if BlobVault implementation requires transaction to flush blobs when StoreTransaction.flush() or StoreTransaction.commit() is called.

Returns:

true if BlobVault implementation requires transaction

flushBlobs

public abstract void flushBlobs(@Nullable
                                @Nullable jetbrains.exodus.core.dataStructures.hash.LongHashMap<java.io.InputStream> blobStreams,
                                @Nullable
                                @Nullable jetbrains.exodus.core.dataStructures.hash.LongHashMap<java.io.File> blobFiles,
                                @Nullable
                                @Nullable jetbrains.exodus.core.dataStructures.hash.LongSet deferredBlobsToDelete,
                                @NotNull
                                @NotNull Transaction txn)
                         throws java.lang.Exception

Method called by PersistentEntityStore to flush blobs identified by blobs. Two maps represent two ways of dealing with blob content: using streams and java.io.File instances. They naturally follow from the Entity API, having two methods to set blob: Entity.setBlob(String, InputStream) and Entity.setBlob(String, File).

The set deferredBlobsToDelete contains blob handles of blobs that should be deleted after the transaction is finished. In most cases, these blobs cannot be deleted immediately without violating isolation transaction guarantees.

Although transaction passed to the method is @NotNull it can be already finished (check by Transaction.isFinished()). E.g., StoreTransaction.commit() at first commits underlying environment Transaction and then flushes blobs passing instance of committed transaction.

Parameters:

blobStreams - map of blob handles to InputStream instances

blobFiles - map of blob handles to File instances

deferredBlobsToDelete - set of blob handles of blobs that should be deleted after the transaction is finished

txn - Transaction instance

Throws:

java.lang.Exception - something went wrong

See Also:

LongHashMap, LongSet, Transaction

size

public abstract long size()

Returns amount of disk space occupied by the BlobVault. This value is rather "rough" since it does not take into consideration particular file system features of storage device.

Returns:

amount of disk space occupied by the BlobVault

See Also:

PersistentEntityStore.getUsableSpace(), IOUtil.getAdjustedFileLength(File)

clear

public abstract void clear()

Is called on PersistentEntityStore.clear().

close

public abstract void close()

Is called on EntityStore.close().

getStringContent

@Nullable
public final @Nullable java.lang.String getStringContent(long blobHandle,
                                                                    @NotNull
                                                                    @NotNull Transaction txn)
                                                             throws java.io.IOException

Returns string content of blob identified by specified blob handle. String contents cache is used.

Parameters:

blobHandle - blob handle

txn - Transaction instance

Returns:

string content of blob identified by specified blob handle

Throws:

java.io.IOException - if something went wrong

getStringContentCacheHitRate

public final float getStringContentCacheHitRate()

Returns:

hit rate of string contents cache

copyStream

public final java.io.ByteArrayOutputStream copyStream(@NotNull
                                                      @NotNull java.io.InputStream source,
                                                      boolean closeSource)
                                               throws java.io.IOException

Throws:

java.io.IOException

cloneStream

public final jetbrains.exodus.util.ByteArraySizedInputStream cloneStream(@NotNull
                                                                         @NotNull java.io.InputStream source,
                                                                         boolean closeSource)
                                                                  throws java.io.IOException

Throws:

java.io.IOException

cloneFile

public final jetbrains.exodus.util.ByteArraySizedInputStream cloneFile(@NotNull
                                                                       @NotNull java.io.File file)
                                                                throws java.io.IOException

Throws:

java.io.IOException