Class ClosingFileReader

java.lang.Object

javax.imageio.stream.ImageInputStreamImpl

com.ibm.dtfj.corereaders.ClosingFileReader

All Implemented Interfaces:

ResourceReleaser, Closeable, DataInput, AutoCloseable, ImageInputStream

public class ClosingFileReader
extends ImageInputStreamImpl
implements ResourceReleaser

A wrapper around the functionality that we require from RandomAccessFiles but with the added auto-closing functionality that we require. Since it is not always easy to determine who "owns" a file and we do not want to introduce the concept of state, this class will manage all such file ownership. We now also extend javax.imageio.stream.ImageInputStreamImpl as a convenient common interface that we can share with the zebedee corefile reader

Field Summary

Fields declared in class ImageInputStreamImpl

bitOffset, byteOrder, flushedPos, streamPos

Constructor Summary

Constructors

Constructor	Description
ClosingFileReader(File file)
ClosingFileReader(File file, boolean deleteOnCloseOrExit)	Create a closing file reader which can close/delete the backing file on shutdown
ClosingFileReader(ImageInputStream file)	Create a closing file reader from a stream

Method Summary

Modifier and Type	Method	Description
void	finalize()	Called by the virtual machine when there are no longer any (non-weak) references to the receiver.
String	getAbsolutePath()
URI	getURIOfFile()
boolean	isMVSFile()
int	read()	Reads a single byte from the stream and returns it as an int between 0 and 255.
int	read(byte[] buffer)	Currently this attempts to fill the entire buffer
int	read(byte[] buffer, int bStart, int length)	Reads up to len bytes from the stream, and stores them into b starting at index off.
byte[]	readBytes(int n)
void	releaseResources()
InputStream	streamFromFile()

Methods declared in class ImageInputStreamImpl

checkClosed, close, flush, flushBefore, getBitOffset, getByteOrder, getFlushedPosition, getStreamPosition, isCached, isCachedFile, isCachedMemory, length, mark, readBit, readBits, readBoolean, readByte, readBytes, readChar, readDouble, readFloat, readFully, readFully, readFully, readFully, readFully, readFully, readFully, readFully, readInt, readLine, readLong, readShort, readUnsignedByte, readUnsignedInt, readUnsignedShort, readUTF, reset, seek, setBitOffset, setByteOrder, skipBytes, skipBytes

Methods declared in class Object

clone, equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

ClosingFileReader

public ClosingFileReader(File file)
                  throws IOException

Throws:

IOException

ClosingFileReader

public ClosingFileReader(ImageInputStream file)
                  throws IOException

Create a closing file reader from a stream

Parameters:

file - An ImageInputStream

Throws:

FileNotFoundException

IOException

ClosingFileReader

public ClosingFileReader(File file,
 boolean deleteOnCloseOrExit)
                  throws IOException

Create a closing file reader which can close/delete the backing file on shutdown

Parameters:

file -

deleteOnCloseOrExit - Whether to delete the file when the file is closed or at shutdown

Throws:

FileNotFoundException

IOException

Method Details

readBytes

public byte[] readBytes(int n)
                 throws IOException

Throws:

IOException

finalize

public void finalize()
              throws Throwable

Description copied from class: java.lang.Object

Called by the virtual machine when there are no longer any (non-weak) references to the receiver. Subclasses can use this facility to guarantee that any associated resources are cleaned up before the receiver is garbage collected. Uncaught exceptions which are thrown during the running of the method cause it to terminate immediately, but are otherwise ignored.

Note: The virtual machine assumes that the implementation in class Object is empty.

Overrides:

finalize in class Object

Throws:

Throwable - The virtual machine ignores any exceptions which are thrown during finalization.

read

public int read(byte[] buffer,
 int bStart,
 int length)
         throws IOException

Description copied from class: javax.imageio.stream.ImageInputStreamImpl

Reads up to len bytes from the stream, and stores them into b starting at index off. If no bytes can be read because the end of the stream has been reached, -1 is returned.

The bit offset within the stream must be reset to zero before the read occurs.

Subclasses must provide an implementation for this method. The subclass implementation should update the stream position before exiting.

Specified by:

read in interface ImageInputStream

Specified by:

read in class ImageInputStreamImpl

Parameters:

buffer -

bStart -

length -

Returns:

The number of bytes actually read

Throws:

IOException

read

public int read(byte[] buffer)
         throws IOException

Currently this attempts to fill the entire buffer

Specified by:

read in interface ImageInputStream

Overrides:

read in class ImageInputStreamImpl

Parameters:

buffer - an array of bytes to be written to.

Returns:

the number of bytes actually read, or -1 to indicate EOF.

Throws:

IOException - if an I/O error occurs.

read

public int read()
         throws IOException

Description copied from class: javax.imageio.stream.ImageInputStreamImpl

Reads a single byte from the stream and returns it as an int between 0 and 255. If EOF is reached, -1 is returned.

Subclasses must provide an implementation for this method. The subclass implementation should update the stream position before exiting.

The bit offset within the stream must be reset to zero before the read occurs.

Specified by:

read in interface ImageInputStream

Specified by:

read in class ImageInputStreamImpl

Returns:

the value of the next byte in the stream, or -1 if EOF is reached.

Throws:

IOException - if the stream has been closed.

streamFromFile

public InputStream streamFromFile()
                           throws FileNotFoundException

Returns:

A new stream for reading from the underlying file

Throws:

FileNotFoundException - If this file has moved since the ClosingFileReader was created (since we would have failed in the constructor if the file was ever there)

getURIOfFile

public URI getURIOfFile()

getAbsolutePath

public String getAbsolutePath()

isMVSFile

public boolean isMVSFile()

releaseResources

public void releaseResources()
                      throws IOException

Specified by:

releaseResources in interface ResourceReleaser

Throws:

IOException