Package com.azure.storage.common

Class StorageInputStream

java.lang.Object
java.io.InputStream
com.azure.storage.common.StorageInputStream
All Implemented Interfaces:
Closeable, AutoCloseable
Direct Known Subclasses:
BlobInputStream, StorageFileInputStream
public abstract class StorageInputStream extends InputStream
Provides an input stream to read a given storage resource.

  • 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.

  • 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.

  • Method Summary

    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 array b.
    int
    read(byte[] b, int off, int len)
    Reads up to len 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, skipNBytes, transferTo

    Methods inherited from class java.lang.Object

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

  • Field Details

    • 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.

    • lastError

      protected IOException lastError
      Holds the last exception this stream encountered.

    • bufferStartOffset

      protected long bufferStartOffset
      Holds the absolute byte position of the start of the current buffer.

    • bufferSize

      protected int bufferSize
      Holds the length of the current buffer in bytes.

  • Constructor Details

    • 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.

    • 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 less than or equal to 0.

    • 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 less than or equal to 0.

  • Method Details

    • 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 class InputStream
      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.

    • close

      public void close()
      Closes this input stream and releases any system resources associated with the stream.
      Specified by:
      close in interface AutoCloseable
      Specified by:
      close in interface Closeable
      Overrides:
      close in class InputStream

    • 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 - An int 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.

    • 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 class InputStream
      Parameters:
      readlimit - An int which represents the maximum limit of bytes that can be read before the mark position becomes invalid.

    • markSupported

      public boolean markSupported()
      Tests if this input stream supports the mark and reset methods. Whether mark and reset are supported is an invariant property of a particular input stream instance. The markSupported method of InputStream returns false.
      Overrides:
      markSupported in class InputStream
      Returns:
      True if this stream instance supports the mark and reset methods; False otherwise.

    • 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 class InputStream
      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.

    • read

      public int read(byte[] b) throws IOException
      Reads some number of bytes from the input stream and stores them into the buffer array b. 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 of b 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 into b. The first byte read is stored into element b[0], the next one into b[1], and so on. The number of bytes read is, at most, equal to the length of b. Let k be the number of bytes actually read; these bytes will be stored in elements b[0] through b[k-1], leaving elements b[k] through b[b.length-1] unaffected. The read(b) method for class InputStream has the same effect as: read(b, 0, b.length)
      Overrides:
      read in class InputStream
      Parameters:
      b - A byte 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 the byte array b is null.

    • read

      public int read(byte[] b, int off, int len) throws IOException
      Reads up to len bytes of data from the input stream into an array of bytes. An attempt is made to read as many as len 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. If len 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 into b. The first byte read is stored into element b[off], the next one into b[off+1], and so on. The number of bytes read is, at most, equal to len. Let k be the number of bytes actually read; these bytes will be stored in elements b[off] through b[off+k-1], leaving elements b[off+k] through b[off+len-1] unaffected. In every case, elements b[0] through b[off] and elements b[off+len] through b[b.length-1] are unaffected. The read(b, off, len) method for class InputStream simply calls the method read() repeatedly. If the first such call results in an IOException, that exception is returned from the call to the read(b, off, len) method. If any subsequent call to read() results in a IOException, the exception is caught and treated as if it were end of file; the bytes read up to that point are stored into b 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 data len 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 class InputStream
      Parameters:
      b - A byte array which represents the buffer into which the data is read.
      off - An int which represents the start offset in the byte array at which the data is written.
      len - An int 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 the byte array b is null.
      IndexOutOfBoundsException - If off is negative, len is negative, or len is greater than b.length - off.

    • 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 class InputStream
      Throws:
      RuntimeException - If this stream has not been marked or if the mark has been invalidated.

    • 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 class InputStream
      Parameters:
      n - A long which represents the number of bytes to skip.