Interface BlobStore
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- All Known Implementing Classes:
AbstractBlobStore
,AESBlobStore
,CachingBlobStore
,InMemoryBlobStore
,LocalBlobStore
,S3BlobStore
,TransactionalBlobStore
public interface BlobStore
Interface for basic access to storage of a Blob (read/write/copy/delete).A blob is identified by a key, and holds a stream of bytes. It may have some associated metadata (filename, content type).
A blob store may have versioning. When this is the case, the write method will return a key that includes a version number. This same complete key must subsequently be provided to the read or delete methods. With versioning, two writes may be requested with the same key in the blob context, and both will succeed because they return keys that include a version number to distinguish them.
- Since:
- 11.1
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Nested Class Summary
Nested Classes Modifier and Type Interface Description static class
BlobStore.OptionalOrUnknown<T>
A class representing an unknown value, a missing value, or a present (non-null) value.
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Method Summary
All Methods Instance Methods Abstract Methods Modifier and Type Method Description boolean
copyBlob(String key, BlobStore sourceStore, String sourceKey, boolean atomicMove)
Writes a file based on a key, as a copy/move from a source in another blob store.boolean
copyBlobIsOptimized(BlobStore sourceStore)
Checks if blob copy/move from another blob store to this one can be done efficiently.void
deleteBlob(String key)
Deletes a blob based on a key.void
deleteBlob(BlobContext blobContext)
Deletes a blob.BinaryGarbageCollector
getBinaryGarbageCollector()
Returns the binary garbage collector (GC).BlobStore.OptionalOrUnknown<Path>
getFile(String key)
Gets an already-existing file containing the blob for the given key, if present.KeyStrategy
getKeyStrategy()
Gets the key strategy used by the store.String
getName()
Name used for debugging / tracing.BlobStore.OptionalOrUnknown<InputStream>
getStream(String key)
Gets the stream of the blob for the given key, if present.boolean
hasVersioning()
Whether this blob store has versioning.boolean
readBlob(String key, Path dest)
Reads a blob based on its key into the given file.BlobStore
unwrap()
If this blob store wraps another one, returns it, otherwise returns this.String
writeBlob(BlobContext blobContext)
Writes a blob.String
writeBlob(BlobWriteContext blobWriteContext)
Writes a blob.void
writeBlobProperties(BlobUpdateContext blobUpdateContext)
Sets properties on a blob.
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Method Detail
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hasVersioning
boolean hasVersioning()
Whether this blob store has versioning.With versioning, two writes may use the same key. The returned keys will include a different version number to distinguish the writes.
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getKeyStrategy
KeyStrategy getKeyStrategy()
Gets the key strategy used by the store.
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writeBlob
String writeBlob(BlobContext blobContext) throws IOException
Writes a blob.- Parameters:
blobContext
- the blob context- Returns:
- the blob key
- Throws:
IOException
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writeBlob
String writeBlob(BlobWriteContext blobWriteContext) throws IOException
Writes a blob.Note that the returned key may be different than the one requested by the
BlobWriteContext
, if the blob store needs additional version info to retrieve it.- Parameters:
blobWriteContext
- the context of the blob write, including the blob- Returns:
- the key to use to read this blob in the future
- Throws:
IOException
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copyBlobIsOptimized
boolean copyBlobIsOptimized(BlobStore sourceStore)
Checks if blob copy/move from another blob store to this one can be done efficiently.- Parameters:
sourceStore
- the source store- Returns:
true
if the copy/move can be done efficiently
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copyBlob
boolean copyBlob(String key, BlobStore sourceStore, String sourceKey, boolean atomicMove) throws IOException
Writes a file based on a key, as a copy/move from a source in another blob store.If the copy/move is requested to be atomic, then the destination file is created atomically. In case of atomic move, in some stores the destination will be created atomically but the source will only be deleted afterwards.
- Parameters:
key
- the keysourceStore
- the source storesourceKey
- the source keyatomicMove
-true
for an atomic move,false
for a regular copy- Returns:
true
if the file was found in the source store,false
if it was not found- Throws:
IOException
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getFile
@NotNull BlobStore.OptionalOrUnknown<Path> getFile(String key)
Gets an already-existing file containing the blob for the given key, if present.Note that this method is best-effort, it may return unknown even though the blob exists in the store, it's just that it's not handily available locally in a file.
- Parameters:
key
- the blob key- Returns:
- the file containing the blob, or empty if the blob cannot be found, or unknown if no file is available locally
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getStream
@NotNull BlobStore.OptionalOrUnknown<InputStream> getStream(String key) throws IOException
Gets the stream of the blob for the given key, if present.Note that this method is best-effort, it may return unknown even though the blob exists in the store, it's just that it's not efficient to return it as a stream.
- Parameters:
key
- the blob key- Returns:
- the blob stream, or empty if the blob cannot be found, or unknown if no stream is efficiently available
- Throws:
IOException
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readBlob
boolean readBlob(String key, Path dest) throws IOException
Reads a blob based on its key into the given file.- Parameters:
key
- the blob keydest
- the file to use to store the fetched data- Returns:
true
if the file was fetched,false
if the file was not found- Throws:
IOException
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writeBlobProperties
void writeBlobProperties(BlobUpdateContext blobUpdateContext) throws IOException
Sets properties on a blob.- Parameters:
blobUpdateContext
- the blob update context- Throws:
IOException
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deleteBlob
void deleteBlob(BlobContext blobContext)
Deletes a blob.- Parameters:
blobContext
- the blob context
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deleteBlob
void deleteBlob(String key)
Deletes a blob based on a key. No error occurs if the blob does not exist.This method does not throw
IOException
, but may log an error message.- Parameters:
key
- the blob key
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getBinaryGarbageCollector
BinaryGarbageCollector getBinaryGarbageCollector()
Returns the binary garbage collector (GC).Several calls to this method will return the same GC, so that its status can be monitored using
BinaryGarbageCollector.isInProgress()
.- Returns:
- the binary GC
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