Class MonitorableInputStream
- All Implemented Interfaces:
Monitorable
,Closeable
,AutoCloseable
- Direct Known Subclasses:
MonitorableFileInputStream
public class MonitorableInputStream extends FilterInputStream implements Monitorable
- Author:
- Lennart Martens
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Field Summary
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Constructor Summary
Constructors Constructor Description MonitorableInputStream(InputStream aIn)
A MonitorableInputStream can only be constructed around an existing InputStream.MonitorableInputStream(InputStream aIn, boolean aBypassCache)
A MonitorableInputStream can only be constructed around an existing InputStream.MonitorableInputStream(InputStream aIn, int aMaximum)
A MonitorableInputStream can only be constructed around an existing InputStream. -
Method Summary
Modifier and Type Method Description int
getMaximum()
This method reports on the total amount of bytes that can be read from the monitored InputStream.int
monitorProgress()
This method returns the progress (as measured by taking the value of iMaximum, minus the current available bytes as reported by the underlying InputStream - variable iRemainder).int
read()
Reads the next byte of data from this input stream.int
read(byte[] b)
Reads up tobyte.length
bytes of data from this input stream into an array of bytes.int
read(byte[] b, int off, int len)
Reads up tolen
bytes of data from this input stream into an array of bytes.void
reset()
Repositions this stream to the position at the time themark
method was last called on this input stream.long
skip(long n)
Skips over and discardsn
bytes of data from the input stream.Methods inherited from class java.io.InputStream
nullInputStream, readAllBytes, readNBytes, readNBytes, skipNBytes, transferTo
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Constructor Details
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MonitorableInputStream
A MonitorableInputStream can only be constructed around an existing InputStream. This InputStream will be the one monitored.- Parameters:
aIn
- InputStream to monitor.- Throws:
IOException
- when something is wrong with the InpuStream.
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MonitorableInputStream
A MonitorableInputStream can only be constructed around an existing InputStream. This InputStream will be the one monitored. This constructor allows the setting of the maximum readsize. It is useful when monitoring certain files, which cannot report on the available bytes.- Parameters:
aIn
- InputStream to monitor.aMaximum
- int with the maximum number of bytes that can be read.- Throws:
IOException
- when something is wrong with the InpuStream.
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MonitorableInputStream
A MonitorableInputStream can only be constructed around an existing InputStream. This InputStream will be the one monitored. This constructor can instruct the instance to bypass the progress cache and update the information directly. This is useful when monitoring read progress in zipfiles, which cannot report on the available bytes, and whose underlying streams are masked by a PushBackInputStream.- Parameters:
aIn
- InputStream to monitor.aBypassCache
- boolean that indicates whether the cache should be bypassed.- Throws:
IOException
- when something is wrong with the InpuStream.
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Method Details
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getMaximum
public int getMaximum()This method reports on the total amount of bytes that can be read from the monitored InputStream.- Specified by:
getMaximum
in interfaceMonitorable
- Returns:
- int with the total bytes that can be read from the InputStream.
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monitorProgress
public int monitorProgress()This method returns the progress (as measured by taking the value of iMaximum, minus the current available bytes as reported by the underlying InputStream - variable iRemainder).- Specified by:
monitorProgress
in interfaceMonitorable
- Returns:
- int with the progress.
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read
Reads up tobyte.length
bytes of data from this input stream into an array of bytes. This method blocks until some input is available.This method simply performs the call
read(b, 0, b.length)
and returns the result. It is important that it does not doin.read(b)
instead; certain subclasses ofFilterInputStream
depend on the implementation strategy actually used.- Overrides:
read
in classFilterInputStream
- Parameters:
b
- the buffer into which the data is read.- Returns:
- the total number of bytes read into the buffer, or
-1
if there is no more data because the end of the stream has been reached. - Throws:
IOException
- if an I/O error occurs.- See Also:
FilterInputStream.read(byte[], int, int)
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read
Reads the next byte of data from this input stream. The value byte is returned as anint
in the range0
to255
. If no byte is available because the end of the stream has been reached, the value-1
is returned. This method blocks until input data is available, the end of the stream is detected, or an exception is thrown.This method simply performs
in.read()
and returns the result.- Overrides:
read
in classFilterInputStream
- Returns:
- the next byte of data, or
-1
if the end of the stream is reached. - Throws:
IOException
- if an I/O error occurs.- See Also:
FilterInputStream.in
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read
Reads up tolen
bytes of data from this input stream into an array of bytes. This method blocks until some input is available.This method simply performs
in.read(b, off, len)
and returns the result.- Overrides:
read
in classFilterInputStream
- Parameters:
b
- the buffer into which the data is read.off
- the start offset of the data.len
- the maximum number of bytes read.- Returns:
- the total number of bytes read into the buffer, or
-1
if there is no more data because the end of the stream has been reached. - Throws:
IOException
- if an I/O error occurs.- See Also:
FilterInputStream.in
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skip
Skips over and discardsn
bytes of data from the input stream. Theskip
method may, for a variety of reasons, end up skipping over some smaller number of bytes, possibly0
. The actual number of bytes skipped is returned.This method simply performs
in.skip(n)
.- Overrides:
skip
in classFilterInputStream
- Parameters:
n
- the number of bytes to be skipped.- Returns:
- the actual number of bytes skipped.
- Throws:
IOException
- if an I/O error occurs.
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reset
Repositions this stream to the position at the time themark
method was last called on this input stream.This method simply performs
in.reset()
.Stream marks are intended to be used in situations where you need to read ahead a little to see what's in the stream. Often this is most easily done by invoking some general parser. If the stream is of the type handled by the parse, it just chugs along happily. If the stream is not of that type, the parser should toss an exception when it fails. If this happens within readlimit bytes, it allows the outer code to reset the stream and try another parser.
- Overrides:
reset
in classFilterInputStream
- Throws:
IOException
- if the stream has not been marked or if the mark has been invalidated.- See Also:
FilterInputStream.in
,FilterInputStream.mark(int)
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