com.qcloud.cos.internal

Class ResettableInputStream

java.lang.Object

java.io.InputStream

java.io.FilterInputStream

com.qcloud.cos.internal.SdkFilterInputStream

com.qcloud.cos.internal.ReleasableInputStream

com.qcloud.cos.internal.ResettableInputStream

All Implemented Interfaces:

Releasable, Closeable, AutoCloseable

public class ResettableInputStream
extends ReleasableInputStream

A mark-and-resettable input stream that can be used on files or file input streams. In particular, a ResettableInputStream allows the close operation to be disabled via ReleasableInputStream.disableClose() (to avoid accidentally being closed). This is necessary when such input stream needs to be marked-and-reset multiple times but only as long as the stream has not been closed.

The creator of this input stream should therefore always call ReleasableInputStream.release() in a finally block to truly release the underlying resources.

See Also:

Releasable

Field Summary

Fields inherited from class java.io.FilterInputStream

in

Constructor Summary

Constructors

Constructor and Description
ResettableInputStream(File file)
ResettableInputStream(FileInputStream fis)

Method Summary

Modifier and Type	Method and Description
int	available()
File	getFile() Returns the underlying file, if known; or null if not;
void	mark(int _) Marks the current position in this input stream.
boolean	markSupported()
static ResettableInputStream	newResettableInputStream(File file) Convenient factory method to construct a new resettable input stream for the given file, converting any IOException into CosClientException.
static ResettableInputStream	newResettableInputStream(FileInputStream fis) Convenient factory method to construct a new resettable input stream for the given file input stream, converting any IOException into CosClientException.
static ResettableInputStream	newResettableInputStream(FileInputStream fis, String errmsg) Convenient factory method to construct a new resettable input stream for the given file input stream, converting any IOException into CosClientException with the given error message.
static ResettableInputStream	newResettableInputStream(File file, String errmsg) Convenient factory method to construct a new resettable input stream for the given file, converting any IOException into CosClientException with the given error message.
int	read()
int	read(byte[] arg0, int arg1, int arg2)
void	reset() Repositions this stream to the position at the time the mark method was last called on this input stream.
long	skip(long n)

Methods inherited from class com.qcloud.cos.internal.ReleasableInputStream

close, disableClose, isCloseDisabled, release, wrap

Methods inherited from class com.qcloud.cos.internal.SdkFilterInputStream

abort, abortIfNeeded, isAborted

Methods inherited from class java.io.FilterInputStream

read

Methods inherited from class java.lang.Object

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

Constructor Detail

ResettableInputStream

public ResettableInputStream(File file)
                      throws IOException

Parameters:

file - must not be null. Upon successful construction the the file will be opened with an input stream automatically marked at the starting position of the given file.

Note the creation of a ResettableInputStream would entail physically opening a file. If the opened file is meant to be closed only (in a finally block) by the very same code block that created it, then it is necessary that the release method must not be called while the execution is made in other stack frames. In such case, as other stack frames may inadvertently or indirectly call the close method of the stream, the creator of the stream would need to explicitly disable the accidental closing via ReleasableInputStream.disableClose(), so that the release method becomes the only way to truly close the opened file.

Throws:

IOException

ResettableInputStream

public ResettableInputStream(FileInputStream fis)
                      throws IOException

Parameters:

fis - file input stream; must not be null. Upon successful construction the input stream will be automatically marked at the current position of the given file input stream.

Note the creation of a ResettableInputStream would entail physically opening a file. If the opened file is meant to be closed only (in a finally block) by the very same code block that created it, then it is necessary that the release method must not be called while the execution is made in other stack frames. In such case, as other stack frames may inadvertently or indirectly call the close method of the stream, the creator of the stream would need to explicitly disable the accidental closing via ReleasableInputStream.disableClose(), so that the release method becomes the only way to truly close the opened file.

Throws:

IOException

Method Detail

markSupported

public final boolean markSupported()

Overrides:

markSupported in class SdkFilterInputStream

mark

public void mark(int _)

Marks the current position in this input stream. A subsequent call to the reset method repositions this stream at the last marked position so that subsequent reads re-read the same bytes. This method works as long as the underlying file has not been closed.

Note the creation of a ResettableInputStream would entail physically opening a file. If the opened file is meant to be closed only (in a finally block) by the very same code block that created it, then it is necessary that the release method must not be called while the execution is made in other stack frames. In such case, as other stack frames may inadvertently or indirectly call the close method of the stream, the creator of the stream would need to explicitly disable the accidental closing via ReleasableInputStream.disableClose(), so that the release method becomes the only way to truly close the opened file.

Overrides:

mark in class SdkFilterInputStream

Parameters:

_ - ignored

reset

public void reset()
           throws IOException

Repositions this stream to the position at the time the mark method was last called on this input stream. This method works as long as the underlying file has not been closed.

Note the creation of a ResettableInputStream would entail physically opening a file. If the opened file is meant to be closed only (in a finally block) by the very same code block that created it, then it is necessary that the release method must not be called while the execution is made in other stack frames. In such case, as other stack frames may inadvertently or indirectly call the close method of the stream, the creator of the stream would need to explicitly disable the accidental closing via ReleasableInputStream.disableClose(), so that the release method becomes the only way to truly close the opened file.

Overrides:

reset in class SdkFilterInputStream

Throws:

IOException

available

public int available()
              throws IOException

Overrides:

available in class SdkFilterInputStream

Throws:

IOException

read

public int read()
         throws IOException

Overrides:

read in class SdkFilterInputStream

Throws:

IOException

skip

public long skip(long n)
          throws IOException

Overrides:

skip in class SdkFilterInputStream

Throws:

IOException

read

public int read(byte[] arg0,
                int arg1,
                int arg2)
         throws IOException

Overrides:

read in class SdkFilterInputStream

Throws:

IOException

getFile

public File getFile()

Returns the underlying file, if known; or null if not;

newResettableInputStream

public static ResettableInputStream newResettableInputStream(File file)

Convenient factory method to construct a new resettable input stream for the given file, converting any IOException into CosClientException.

Note the creation of a ResettableInputStream would entail physically opening a file. If the opened file is meant to be closed only (in a finally block) by the very same code block that created it, then it is necessary that the release method must not be called while the execution is made in other stack frames. In such case, as other stack frames may inadvertently or indirectly call the close method of the stream, the creator of the stream would need to explicitly disable the accidental closing via ReleasableInputStream.disableClose(), so that the release method becomes the only way to truly close the opened file.

newResettableInputStream

public static ResettableInputStream newResettableInputStream(File file,
                                                             String errmsg)

Convenient factory method to construct a new resettable input stream for the given file, converting any IOException into CosClientException with the given error message.

Note the creation of a ResettableInputStream would entail physically opening a file. If the opened file is meant to be closed only (in a finally block) by the very same code block that created it, then it is necessary that the release method must not be called while the execution is made in other stack frames. In such case, as other stack frames may inadvertently or indirectly call the close method of the stream, the creator of the stream would need to explicitly disable the accidental closing via ReleasableInputStream.disableClose(), so that the release method becomes the only way to truly close the opened file.

newResettableInputStream

public static ResettableInputStream newResettableInputStream(FileInputStream fis)

Convenient factory method to construct a new resettable input stream for the given file input stream, converting any IOException into CosClientException.

Note the creation of a ResettableInputStream would entail physically opening a file. If the opened file is meant to be closed only (in a finally block) by the very same code block that created it, then it is necessary that the release method must not be called while the execution is made in other stack frames. In such case, as other stack frames may inadvertently or indirectly call the close method of the stream, the creator of the stream would need to explicitly disable the accidental closing via ReleasableInputStream.disableClose(), so that the release method becomes the only way to truly close the opened file.

newResettableInputStream

public static ResettableInputStream newResettableInputStream(FileInputStream fis,
                                                             String errmsg)

Convenient factory method to construct a new resettable input stream for the given file input stream, converting any IOException into CosClientException with the given error message.

Note the creation of a ResettableInputStream would entail physically opening a file. If the opened file is meant to be closed only (in a finally block) by the very same code block that created it, then it is necessary that the release method must not be called while the execution is made in other stack frames. In such case, as other stack frames may inadvertently or indirectly call the close method of the stream, the creator of the stream would need to explicitly disable the accidental closing via ReleasableInputStream.disableClose(), so that the release method becomes the only way to truly close the opened file.