net.sf.jasperreports.engine.util
public class JRSwapFile extends java.lang.Object
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.
Modifier and Type | Class and Description |
---|---|
protected static class |
JRSwapFile.LongQueue |
static class |
JRSwapFile.SwapHandle |
Modifier and Type | Field and Description |
---|---|
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 and Description |
---|
JRSwapFile(java.lang.String directory,
int blockSize,
int minGrowCount)
Creates a swap file.
|
Modifier and Type | Method and Description |
---|---|
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) |
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
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 fullpublic JRSwapFile.SwapHandle write(byte[] data) throws java.io.IOException
data
- the data for which to allocate an area in the filejava.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 readingjava.io.IOException
protected void read(byte[] data, int dataOffset, int dataLength, long fileOffset) throws java.io.IOException
java.io.IOException
public void free(JRSwapFile.SwapHandle handle)
handle
- the allocated area handlepublic void dispose()
protected void finalize() throws java.lang.Throwable
finalize
in class java.lang.Object
java.lang.Throwable
protected long[] reserveFreeBlocks(int blockCount) throws java.io.IOException
java.io.IOException
protected void freeBlocks(long[] offsets)
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