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java.lang.Objectnet.sf.jasperreports.engine.util.JRSwapFile
public class JRSwapFile
Swap file implementation that can be used as a disk cache for arbitrary binary data.
Fixed-size blocks are allocated inside the swap file when a caller wants to write data. The caller receives a handle to the allocated area based on which it can read the data or free the area.
The implementation is thread-safe. I/O operations are performed in synchronized blocks, only one thread would do a read or write at one moment.
| Nested Class Summary | |
|---|---|
protected static class |
JRSwapFile.LongQueue
|
static class |
JRSwapFile.SwapHandle
|
| Field Summary | |
|---|---|
protected java.io.RandomAccessFile |
file
|
static java.lang.String |
PROPERTY_DELETE_ON_EXIT
Property that instructs whether deleteOnExit is to be requested
for swap files. |
| Constructor Summary | |
|---|---|
JRSwapFile(java.lang.String directory,
int blockSize,
int minGrowCount)
Creates a swap file. |
|
| Method Summary | |
|---|---|
void |
dispose()
Closes and deletes the swap file. |
protected void |
finalize()
|
void |
free(JRSwapFile.SwapHandle handle)
Frees an allocated area. |
protected void |
freeBlocks(long[] offsets)
|
protected void |
read(byte[] data,
int dataOffset,
int dataLength,
long fileOffset)
|
byte[] |
read(JRSwapFile.SwapHandle handle,
boolean free)
Reads all the data from an allocated area. |
protected long[] |
reserveFreeBlocks(int blockCount)
|
JRSwapFile.SwapHandle |
write(byte[] data)
Allocates an area in the swap file and writes data in it. |
protected void |
write(byte[] data,
int dataSize,
int dataOffset,
long fileOffset)
|
| Methods inherited from class java.lang.Object |
|---|
clone, equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
| Field Detail |
|---|
public static final java.lang.String PROPERTY_DELETE_ON_EXIT
deleteOnExit is to be requested
for swap files.
Swap files are explicitly deleted on dispose() and garbage collection.
protected final java.io.RandomAccessFile file
| Constructor Detail |
|---|
public JRSwapFile(java.lang.String directory,
int blockSize,
int minGrowCount)
directory - the directory where the file should be created.blockSize - the size of the blocks allocated by the swap fileminGrowCount - the minimum number of blocks by which the swap file grows when full| Method Detail |
|---|
public JRSwapFile.SwapHandle write(byte[] data)
throws java.io.IOException
data - the data for which to allocate an area in the file
java.io.IOException
protected void write(byte[] data,
int dataSize,
int dataOffset,
long fileOffset)
throws java.io.IOException
java.io.IOException
public byte[] read(JRSwapFile.SwapHandle handle,
boolean free)
throws java.io.IOException
handle - the allocated area handlefree - whether to free the area after reading
java.io.IOException
protected void read(byte[] data,
int dataOffset,
int dataLength,
long fileOffset)
throws java.io.IOException
java.io.IOExceptionpublic void free(JRSwapFile.SwapHandle handle)
handle - the allocated area handlepublic void dispose()
protected void finalize()
throws java.lang.Throwable
finalize in class java.lang.Objectjava.lang.Throwable
protected long[] reserveFreeBlocks(int blockCount)
throws java.io.IOException
java.io.IOExceptionprotected void freeBlocks(long[] offsets)
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