BlockAccess (Apache Jena - DBOE Base 4.2.0)

All Superinterfaces:

org.apache.jena.atlas.lib.Closeable, org.apache.jena.atlas.lib.Sync

All Known Implementing Classes:

BlockAccessBase, BlockAccessByteArray, BlockAccessDirect, BlockAccessMapped, BlockAccessMem
```
public interface BlockAccess
extends org.apache.jena.atlas.lib.Sync, org.apache.jena.atlas.lib.Closeable
```
Interface to concrete storage - read and write Blocks, addressed by id. Suitable for memory mapped I/O (returns internally allocated space for read, not provided from outside; write() can insist the block written comes from allocate()). This interface can also be backed by an in-memory implementation (BlockAccessMem, BlockAccessByteArray). This is wrapped in a BlockMgr to provide a higher level abstraction.

See Also:

BufferChannel

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method	Description
`Block`	`allocate(int size)`
`long`	`allocBoundary()`
`java.lang.String`	`getLabel()`
`boolean`	`isEmpty()`
`void`	`overwrite(Block block)`
`Block`	`read(long id)`
`void`	`resetAllocBoundary(long boundary)`	Reset the allocation space (i.e.
`boolean`	`valid(long id)`
`void`	`write(Block block)`

Methods inherited from interface org.apache.jena.atlas.lib.Closeable
close

Methods inherited from interface org.apache.jena.atlas.lib.Sync
sync

- Method Detail
  - allocate
```
Block allocate(int size)
```
  - read
```
Block read(long id)
```
  - write
```
void write(Block block)
```
  - overwrite
```
void overwrite(Block block)
```
  - isEmpty
```
boolean isEmpty()
```
  - allocBoundary
```
long allocBoundary()
```
  - resetAllocBoundary
```
void resetAllocBoundary(long boundary)
```
    Reset the allocation space (i.e. truncate). The boundary should be a number obtained from a previous call of allocLimit. It can not be greater than the current allocation boundary.
  - valid
```
boolean valid(long id)
```
  - getLabel
```
java.lang.String getLabel()
```