Package com.globalmentor.io

Class CaptureInputStream

  • All Implemented Interfaces:
    Disposable, java.io.Closeable, java.lang.AutoCloseable
    public class CaptureInputStream
extends InputStreamDecorator<java.io.InputStream>
    An input stream that captures all transferred bytes of a decorated stream.
    Author:
    Garret Wilson

    • Constructor Summary

      Constructors 
      Constructor Description
      CaptureInputStream​(java.io.InputStream inputStream)
      Decorates the given input stream.

    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      void clearCapturedBytes()
      Clears all accumulated captured bytes.
      byte[] getCapturedBytes()  
      byte[] getCapturedBytes​(boolean clearCapturedBytes)
      Returns all captured bytes accumulated from transfers since the captured bytes were last cleared.
      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.
      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

      • Methods inherited from class java.lang.Object

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

    • Constructor Detail

      • CaptureInputStream

        public CaptureInputStream​(java.io.InputStream inputStream)
        Decorates the given input stream.
        Parameters:
        inputStream - The input stream to decorate.
        Throws:
        java.lang.NullPointerException - if the given stream is null.

    • Method Detail

      • getCapturedBytes

        public byte[] getCapturedBytes()
        Returns:
        The current captured data accumulated from transfers, leaving the data to be retrieved again at a future time.

      • getCapturedBytes

        public byte[] getCapturedBytes​(boolean clearCapturedBytes)
        Returns all captured bytes accumulated from transfers since the captured bytes were last cleared. This method allows the captured data to be atomically cleared at the same time that data is retrieved so that no data is lost.
        Parameters:
        clearCapturedBytes - Whether the captured data should be cleared after retrieving the data.
        Returns:
        The current captured data accumulated from transfers.
        See Also:
        clearCapturedBytes()

      • clearCapturedBytes

        public void clearCapturedBytes()
        Clears all accumulated captured bytes.

      • read

        public int read()
         throws java.io.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.

        A subclass must provide an implementation of this method.

        Overrides:
        read in class InputStreamDecorator<java.io.InputStream>
        Returns:
        the next byte of data, or -1 if the end of the stream is reached.
        Throws:
        java.io.IOException - if an I/O error occurs.

      • read

        public int read​(byte[] b)
         throws java.io.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 b is null, a NullPointerException 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 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[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.

        If the first byte cannot be read for any reason other than end of file, then an IOException is thrown. In particular, an IOException is thrown if the input stream has been closed.

        The read(b) method for class InputStream has the same effect as: 

          read(b, 0, b.length)
        Overrides:
        read in class InputStreamDecorator<java.io.InputStream>
        Parameters:
        b - the buffer into which the data is read.
        Returns:
        the total number of bytes read into the buffer, or -1 is there is no more data because the end of the stream has been reached.
        Throws:
        java.io.IOException - if an I/O error occurs.
        java.lang.NullPointerException - if b is null.
        See Also:
        InputStream.read(byte[], int, int)

      • read

        public int read​(byte[] b,
                int off,
                int len)
         throws java.io.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 b is null, a NullPointerException is thrown.

        If off is negative, or len is negative, or off+len is greater than the length of the array b, then an IndexOutOfBoundsException 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.

        If the first byte cannot be read for any reason other than end of file, then an IOException is thrown. In particular, an IOException is thrown if the input stream has been closed.

        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. Subclasses are encouraged to provide a more efficient implementation of this method.

        Overrides:
        read in class InputStreamDecorator<java.io.InputStream>
        Parameters:
        b - the buffer into which the data is read.
        off - the start offset in array b at which the data is written.
        len - the maximum number of bytes to 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:
        java.io.IOException - if an I/O error occurs.
        java.lang.NullPointerException - if b is null.
        See Also:
        InputStream.read()

      • skip

        public long skip​(long n)
          throws java.io.IOException
        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. This version reads and captures the skipped data.
        Overrides:
        skip in class InputStreamDecorator<java.io.InputStream>
        Parameters:
        n - the number of bytes to be skipped.
        Returns:
        the actual number of bytes skipped.
        Throws:
        java.io.IOException - if an I/O error occurs.