Bucket (fred API)

All Known Subinterfaces:

NotPersistentBucket, RandomAccessBucket

All Known Implementing Classes:

AEADCryptBucket, ArrayBucket, BaseFileBucket, DelayedFreeBucket, DelayedFreeRandomAccessBucket, EncryptedRandomAccessBucket, FileBucket, NoFreeBucket, NullBucket, PaddedBucket, PaddedEphemerallyEncryptedBucket, PaddedRandomAccessBucket, PersistentTempFileBucket, RAFBucket, ReadOnlyFileSliceBucket, SimpleReadOnlyArrayBucket, TempBucketFactory.TempBucket, TempFileBucket
```
public interface Bucket
```
A bucket is any arbitrary object can temporarily store data. In other words, it is the equivalent of a temporary file, but it could be in RAM, on disk, encrypted, part of a file on disk, composed from a chain of other buckets etc. Not all buckets are Serializable.

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method and Description
`Bucket`	`createShadow()` Create a shallow read-only copy of this bucket, using different objects but using the same external storage.
`void`	`free()` Free the bucket, if supported.
`java.io.InputStream`	`getInputStream()` Returns an InputStream that reads data from this Bucket.
`java.io.InputStream`	`getInputStreamUnbuffered()`
`java.lang.String`	`getName()` Returns a name for the bucket, may be used to identify them in certain in certain situations.
`java.io.OutputStream`	`getOutputStream()` Returns an OutputStream that is used to put data in this Bucket, from the beginning.
`java.io.OutputStream`	`getOutputStreamUnbuffered()` Get an OutputStream which is not buffered.
`boolean`	`isReadOnly()` Is the bucket read-only?
`void`	`onResume(ClientContext context)` Called after restarting.
`void`	`setReadOnly()` Make the bucket read-only.
`long`	`size()` Returns the amount of data currently in this bucket in bytes.
`void`	`storeTo(java.io.DataOutputStream dos)` Write enough data to reconstruct the Bucket, or throw UnsupportedOperationException.

- Method Detail
  - getOutputStream
```
java.io.OutputStream getOutputStream()
                              throws java.io.IOException
```
    Returns an OutputStream that is used to put data in this Bucket, from the beginning. It is not possible to append data to a Bucket! This simplifies the code significantly for some classes. If you need to append, just pass the OutputStream around. Will be buffered if appropriate (e.g. byte array backed buckets don't need to be buffered).
    
    Throws:
    
    java.io.IOException
  - getOutputStreamUnbuffered
```
java.io.OutputStream getOutputStreamUnbuffered()
                                        throws java.io.IOException
```
    Get an OutputStream which is not buffered. Should be called when we will buffer the stream at a higher level or when we will only be doing large writes (e.g. copying data from one Bucket to another). Does not make any more persistence guarantees than getOutputStream() does, this is just to save memory.
    
    Throws:
    
    java.io.IOException
  - getInputStream
```
java.io.InputStream getInputStream()
                            throws java.io.IOException
```
    Returns an InputStream that reads data from this Bucket. If there is no data in this bucket, null is returned. You have to call Closer.close(inputStream) on the obtained stream to prevent resource leakage.
    
    Throws:
    
    java.io.IOException
  - getInputStreamUnbuffered
```
java.io.InputStream getInputStreamUnbuffered()
                                      throws java.io.IOException
```
    Throws:
    
    java.io.IOException
  - getName
```
java.lang.String getName()
```
    Returns a name for the bucket, may be used to identify them in certain in certain situations.
  - size
```
long size()
```
    Returns the amount of data currently in this bucket in bytes.
  - isReadOnly
```
boolean isReadOnly()
```
    Is the bucket read-only?
  - setReadOnly
```
void setReadOnly()
```
    Make the bucket read-only. Irreversible.
  - free
```
void free()
```
    Free the bucket, if supported. Note that you must call free() even if you haven't used the Bucket (haven't called getOutputStream()) for some kinds of Bucket's, as they may have allocated space (e.g. created a temporary file).
  - createShadow
```
Bucket createShadow()
```
    Create a shallow read-only copy of this bucket, using different objects but using the same external storage. If this is not possible, return null. Note that if the underlying bucket is deleted, the copy will become invalid and probably throw an IOException on read, or possibly return too-short data etc. In some use cases e.g. on fproxy, this is acceptable.
  - onResume
```
void onResume(ClientContext context)
       throws ResumeFailedException
```
    Called after restarting. The Bucket should do any necessary housekeeping after resuming, e.g. registering itself with the appropriate persistent bucket tracker to avoid being garbage-collected. May be called twice, so the Bucket may need to track this internally.
    
    Parameters:
    
    context - All the necessary runtime support will be on this object.
    
    Throws:
    
    ResumeFailedException
  - storeTo
```
void storeTo(java.io.DataOutputStream dos)
      throws java.io.IOException
```
    Write enough data to reconstruct the Bucket, or throw UnsupportedOperationException. Used for recovering in emergencies, should be versioned if necessary.
    
    Throws:
    
    java.io.IOException

Interface Bucket

Method Summary

Method Detail

getOutputStream

getOutputStreamUnbuffered

getInputStream

getInputStreamUnbuffered

getName

size

isReadOnly

setReadOnly

free

createShadow

onResume

storeTo