Package com.azure.storage.common
Class StorageInputStream
- java.lang.Object
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- java.io.InputStream
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- com.azure.storage.common.StorageInputStream
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- All Implemented Interfaces:
Closeable
,AutoCloseable
public abstract class StorageInputStream extends InputStream
Provides an input stream to read a given storage resource.
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Field Summary
Fields Modifier and Type Field Description protected int
bufferSize
Holds the length of the current buffer in bytes.protected long
bufferStartOffset
Holds the absolute byte position of the start of the current buffer.protected IOException
lastError
Holds the last exception this stream encountered.protected boolean
streamFaulted
A flag to determine if the stream is faulted, if so the last error will be thrown on next operation.
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Constructor Summary
Constructors Modifier Constructor Description protected
StorageInputStream(int chunkSize, long contentLength)
Initializes a new instance of the StorageInputStream class.protected
StorageInputStream(long rangeOffset, Long rangeLength, int chunkSize, long contentLength)
Initializes a new instance of the StorageInputStream class.protected
StorageInputStream(long rangeOffset, Long rangeLength, int chunkSize, long contentLength, ByteBuffer initialBuffer)
Initializes a new instance of the StorageInputStream class.
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Method Summary
All Methods Instance Methods Abstract Methods Concrete Methods Modifier and Type Method Description int
available()
Returns an estimate of the number of bytes that can be read (or skipped over) from this input stream without blocking by the next invocation of a method for this input stream.void
close()
Closes this input stream and releases any system resources associated with the stream.protected abstract ByteBuffer
dispatchRead(int readLength, long offset)
Dispatches a read operation of N bytes and updates stream state accordingly.void
mark(int readlimit)
Marks the current position in this input stream.boolean
markSupported()
Tests if this input stream supports the mark and reset methods.int
read()
Reads the next byte of data from the input stream.int
read(byte[] b)
Reads some number of bytes from the input stream and stores them into the buffer arrayb
.int
read(byte[] b, int off, int len)
Reads up tolen
bytes of data from the input stream into an array of bytes.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)
Skips over and discards n bytes of data from this input stream.-
Methods inherited from class java.io.InputStream
nullInputStream, readAllBytes, readNBytes, readNBytes, transferTo
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Field Detail
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streamFaulted
protected volatile boolean streamFaulted
A flag to determine if the stream is faulted, if so the last error will be thrown on next operation.
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lastError
protected IOException lastError
Holds the last exception this stream encountered.
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bufferStartOffset
protected long bufferStartOffset
Holds the absolute byte position of the start of the current buffer.
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bufferSize
protected int bufferSize
Holds the length of the current buffer in bytes.
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Constructor Detail
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StorageInputStream
protected StorageInputStream(int chunkSize, long contentLength)
Initializes a new instance of the StorageInputStream class.- Parameters:
chunkSize
- the size of chunk allowed to pass for storage service request.contentLength
- the actual content length for input data.
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StorageInputStream
protected StorageInputStream(long rangeOffset, Long rangeLength, int chunkSize, long contentLength)
Initializes a new instance of the StorageInputStream class.- Parameters:
rangeOffset
- The offset of the data to begin stream.rangeLength
- How much data the stream should return after blobRangeOffset.chunkSize
- Holds the stream read size.contentLength
- The length of the stream to be transferred.- Throws:
IndexOutOfBoundsException
- when range offset is less than 0 or rangeLength exists but les than or equal to 0.
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StorageInputStream
protected StorageInputStream(long rangeOffset, Long rangeLength, int chunkSize, long contentLength, ByteBuffer initialBuffer)
Initializes a new instance of the StorageInputStream class.- Parameters:
rangeOffset
- The offset of the data to begin stream.rangeLength
- How much data the stream should return after blobRangeOffset.chunkSize
- Holds the stream read size.contentLength
- The length of the stream to be transferred.initialBuffer
- The first chunk of the download. Fetched alongside properties for optimization- Throws:
IndexOutOfBoundsException
- when range offset is less than 0 or rangeLength exists but les than or equal to 0.
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Method Detail
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available
public int available()
Returns an estimate of the number of bytes that can be read (or skipped over) from this input stream without blocking by the next invocation of a method for this input stream. The next invocation might be the same thread or another thread. A single read or skip of this many bytes will not block, but may read or skip fewer bytes.- Overrides:
available
in classInputStream
- Returns:
- An
int
which represents an estimate of the number of bytes that can be read (or skipped over) from this input stream without blocking, or 0 when it reaches the end of the input stream.
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close
public void close()
Closes this input stream and releases any system resources associated with the stream.- Specified by:
close
in interfaceAutoCloseable
- Specified by:
close
in interfaceCloseable
- Overrides:
close
in classInputStream
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dispatchRead
protected abstract ByteBuffer dispatchRead(int readLength, long offset) throws IOException
Dispatches a read operation of N bytes and updates stream state accordingly.- Parameters:
readLength
- Anint
which represents the number of bytes to read.offset
- The start point of data to be acquired.- Returns:
- The bytebuffer which store one chunk size of data.
- Throws:
IOException
- If an I/O error occurs.
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mark
public void mark(int readlimit)
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.- Overrides:
mark
in classInputStream
- Parameters:
readlimit
- Anint
which represents the maximum limit of bytes that can be read before the mark position becomes invalid.
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markSupported
public boolean markSupported()
Tests if this input stream supports the mark and reset methods. Whether or not mark and reset are supported is an invariant property of a particular input stream instance. The markSupported method ofInputStream
returns false.- Overrides:
markSupported
in classInputStream
- Returns:
True
if this stream instance supports the mark and reset methods;False
otherwise.
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read
public int read() throws IOException
Reads the next byte of data from the input stream. The value byte is returned as an int in the range 0 to 255. 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.- Specified by:
read
in classInputStream
- Returns:
- An
int
which represents 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:
RuntimeException
- when no available bytes to read.IOException
- If an I/O error occurs.
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read
public int read(byte[] b) throws IOException
Reads some number of bytes from the input stream and stores them into the buffer arrayb
. The number of bytes actually read is returned as an integer. This method blocks until input data is available, end of file is detected, or an exception is thrown. If the length ofb
is zero, then no bytes are read and 0 is returned; otherwise, there is an attempt to read at least one byte. If no byte is available because the stream is at the end of the file, the value -1 is returned; otherwise, at least one byte is read and stored intob
. The first byte read is stored into elementb[0]
, the next one intob[1]
, and so on. The number of bytes read is, at most, equal to the length ofb
. Letk
be the number of bytes actually read; these bytes will be stored in elementsb[0]
throughb[k-1]
, leaving elementsb[k]
throughb[b.length-1]
unaffected. Theread(b)
method for classInputStream
has the same effect as:read(b, 0, b.length)
- Overrides:
read
in classInputStream
- Parameters:
b
- Abyte
array which represents the buffer into which the data is read.- Throws:
IOException
- If the first byte cannot be read for any reason other than the end of the file, if the input stream has been closed, or if some other I/O error occurs.NullPointerException
- If thebyte
arrayb
is null.
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read
public int read(byte[] b, int off, int len) throws IOException
Reads up tolen
bytes of data from the input stream into an array of bytes. An attempt is made to read as many aslen
bytes, but a smaller number may be read. The number of bytes actually read is returned as an integer. This method blocks until input data is available, end of file is detected, or an exception is thrown. Iflen
is zero, then no bytes are read and 0 is returned; otherwise, there is an attempt to read at least one byte. If no byte is available because the stream is at end of file, the value -1 is returned; otherwise, at least one byte is read and stored intob
. The first byte read is stored into elementb[off]
, the next one intob[off+1]
, and so on. The number of bytes read is, at most, equal tolen
. Letk
be the number of bytes actually read; these bytes will be stored in elementsb[off]
throughb[off+k-1]
, leaving elementsb[off+k]
throughb[off+len-1]
unaffected. In every case, elementsb[0]
throughb[off]
and elementsb[off+len]
throughb[b.length-1]
are unaffected. Theread(b, off, len)
method for classInputStream
simply calls the methodread()
repeatedly. If the first such call results in anIOException
, that exception is returned from the call to theread(b, off, len)
method. If any subsequent call toread()
results in aIOException
, the exception is caught and treated as if it were end of file; the bytes read up to that point are stored intob
and the number of bytes read before the exception occurred is returned. The default implementation of this method blocks until the requested amount of input datalen
has been read, end of file is detected, or an exception is thrown. Subclasses are encouraged to provide a more efficient implementation of this method.- Overrides:
read
in classInputStream
- Parameters:
b
- Abyte
array which represents the buffer into which the data is read.off
- Anint
which represents the start offset in thebyte
array at which the data is written.len
- Anint
which represents the maximum number of bytes to read.- Returns:
- An
int
which represents 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 the first byte cannot be read for any reason other than end of file, or if the input stream has been closed, or if some other I/O error occurs.NullPointerException
- If thebyte
arrayb
is null.IndexOutOfBoundsException
- Ifoff
is negative,len
is negative, orlen
is greater thanb.length - off
.
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reset
public void reset()
Repositions this stream to the position at the time the mark method was last called on this input stream. Note repositioning the blob read stream will disable blob MD5 checking.- Overrides:
reset
in classInputStream
- Throws:
RuntimeException
- If this stream has not been marked or if the mark has been invalidated.
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skip
public long skip(long n)
Skips over and discards n bytes of data from this input stream. The skip method may, for a variety of reasons, end up skipping over some smaller number of bytes, possibly 0. This may result from any of a number of conditions; reaching end of file before n bytes have been skipped is only one possibility. The actual number of bytes skipped is returned. If n is negative, no bytes are skipped. Note repositioning the blob read stream will disable blob MD5 checking.- Overrides:
skip
in classInputStream
- Parameters:
n
- Along
which represents the number of bytes to skip.
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