Package com.google.common.io

Class ByteSource.SlicedByteSource

  • Enclosing class:
    ByteSource
    private final class ByteSource.SlicedByteSource
extends ByteSource
    A view of a subsection of the containing byte source.

    • Field Summary

      Fields 
      Modifier and Type Field Description
      (package private) long length  
      (package private) long offset  

    • Constructor Summary

      Constructors 
      Constructor Description
      SlicedByteSource​(long offset, long length)  

    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      boolean isEmpty()
      Returns whether the source has zero bytes.
      java.io.InputStream openBufferedStream()
      Opens a new buffered InputStream for reading from this source.
      java.io.InputStream openStream()
      Opens a new InputStream for reading from this source.
      Optional<java.lang.Long> sizeIfKnown()
      Returns the size of this source in bytes, if the size can be easily determined without actually opening the data stream.
      ByteSource slice​(long offset, long length)
      Returns a view of a slice of this byte source that is at most length bytes long starting at the given offset.
      private java.io.InputStream sliceStream​(java.io.InputStream in)  
      java.lang.String toString()  

      • Methods inherited from class java.lang.Object

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

    • Field Detail

      • offset

        final long offset

      • length

        final long length

    • Constructor Detail

      • SlicedByteSource

        SlicedByteSource​(long offset,
                 long length)

    • Method Detail

      • openStream

        public java.io.InputStream openStream()
                               throws java.io.IOException
        Description copied from class: ByteSource
        Opens a new InputStream for reading from this source. This method returns a new, independent stream each time it is called.

        The caller is responsible for ensuring that the returned stream is closed.

        Specified by:
        openStream in class ByteSource
        Throws:
        java.io.IOException - if an I/O error occurs while opening the stream

      • openBufferedStream

        public java.io.InputStream openBufferedStream()
                                       throws java.io.IOException
        Description copied from class: ByteSource
        Opens a new buffered InputStream for reading from this source. The returned stream is not required to be a BufferedInputStream in order to allow implementations to simply delegate to ByteSource.openStream() when the stream returned by that method does not benefit from additional buffering (for example, a ByteArrayInputStream). This method returns a new, independent stream each time it is called.

        The caller is responsible for ensuring that the returned stream is closed.

        Overrides:
        openBufferedStream in class ByteSource
        Throws:
        java.io.IOException - if an I/O error occurs while opening the stream

      • sliceStream

        private java.io.InputStream sliceStream​(java.io.InputStream in)
                                 throws java.io.IOException
        Throws:
        java.io.IOException

      • slice

        public ByteSource slice​(long offset,
                        long length)
        Description copied from class: ByteSource
        Returns a view of a slice of this byte source that is at most length bytes long starting at the given offset. If offset is greater than the size of this source, the returned source will be empty. If offset + length is greater than the size of this source, the returned source will contain the slice starting at offset and ending at the end of this source.
        Overrides:
        slice in class ByteSource

      • isEmpty

        public boolean isEmpty()
                throws java.io.IOException
        Description copied from class: ByteSource
        Returns whether the source has zero bytes. The default implementation first checks ByteSource.sizeIfKnown(), returning true if it's known to be zero and false if it's known to be non-zero. If the size is not known, it falls back to opening a stream and checking for EOF.

        Note that, in cases where sizeIfKnown returns zero, it is possible that bytes are actually available for reading. (For example, some special files may return a size of 0 despite actually having content when read.) This means that a source may return true from isEmpty() despite having readable content.

        Overrides:
        isEmpty in class ByteSource
        Throws:
        java.io.IOException - if an I/O error occurs

      • sizeIfKnown

        public Optional<java.lang.Long> sizeIfKnown()
        Description copied from class: ByteSource
        Returns the size of this source in bytes, if the size can be easily determined without actually opening the data stream.

        The default implementation returns Optional.absent(). Some sources, such as a file, may return a non-absent value. Note that in such cases, it is possible that this method will return a different number of bytes than would be returned by reading all of the bytes (for example, some special files may return a size of 0 despite actually having content when read).

        Additionally, for mutable sources such as files, a subsequent read may return a different number of bytes if the contents are changed.

        Overrides:
        sizeIfKnown in class ByteSource

      • toString

        public java.lang.String toString()
        Overrides:
        toString in class java.lang.Object