Package org.apache.commons.io.input

Class ObservableInputStream

java.lang.Object
java.io.InputStream
java.io.FilterInputStream
org.apache.commons.io.input.ProxyInputStream
org.apache.commons.io.input.ObservableInputStream
All Implemented Interfaces:
Closeable, AutoCloseable
Direct Known Subclasses:
MessageDigestCalculatingInputStream
public class ObservableInputStream extends ProxyInputStream
The ObservableInputStream allows, that an InputStream may be consumed by other receivers, apart from the thread, which is reading it. The other consumers are implemented as instances of ObservableInputStream.Observer. A typical application may be the generation of a MessageDigest on the fly. Note: The ObservableInputStream is not thread safe, as instances of InputStream usually aren't. If you must access the stream from multiple threads, then synchronization, locking, or a similar means must be used.
See Also:

  • Field Details

  • Constructor Details

    • ObservableInputStream

      public ObservableInputStream(InputStream pProxy)
      Creates a new ObservableInputStream for the given InputStream.
      Parameters:
      pProxy - the input stream to proxy

  • Method Details

    • add

      public void add(ObservableInputStream.Observer pObserver)
      Adds an Observer.
      Parameters:
      pObserver - the observer to add

    • remove

      public void remove(ObservableInputStream.Observer pObserver)
      Removes an Observer.
      Parameters:
      pObserver - the observer to remove

    • removeAllObservers

      public void removeAllObservers()
      Removes all Observers.

    • read

      public int read() throws IOException
      Description copied from class: ProxyInputStream
      Invokes the delegate's read() method.
      Overrides:
      read in class ProxyInputStream
      Returns:
      the byte read or -1 if the end of stream
      Throws:
      IOException - if an I/O error occurs

    • read

      public int read(byte[] pBuffer) throws IOException
      Description copied from class: ProxyInputStream
      Invokes the delegate's read(byte[]) method.
      Overrides:
      read in class ProxyInputStream
      Parameters:
      pBuffer - the buffer to read the bytes into
      Returns:
      the number of bytes read or EOF if the end of stream
      Throws:
      IOException - if an I/O error occurs

    • read

      public int read(byte[] pBuffer, int pOffset, int pLength) throws IOException
      Description copied from class: ProxyInputStream
      Invokes the delegate's read(byte[], int, int) method.
      Overrides:
      read in class ProxyInputStream
      Parameters:
      pBuffer - the buffer to read the bytes into
      pOffset - The start offset
      pLength - The number of bytes to read
      Returns:
      the number of bytes read or -1 if the end of stream
      Throws:
      IOException - if an I/O error occurs

    • noteDataBytes

      protected void noteDataBytes(byte[] pBuffer, int pOffset, int pLength) throws IOException
      Notifies the observers by invoking ObservableInputStream.Observer.data(byte[],int,int) with the given arguments.
      Parameters:
      pBuffer - Passed to the observers.
      pOffset - Passed to the observers.
      pLength - Passed to the observers.
      Throws:
      IOException - Some observer has thrown an exception, which is being passed down.

    • noteFinished

      protected void noteFinished() throws IOException
      Notifies the observers by invoking ObservableInputStream.Observer.finished().
      Throws:
      IOException - Some observer has thrown an exception, which is being passed down.

    • noteDataByte

      protected void noteDataByte(int pDataByte) throws IOException
      Notifies the observers by invoking ObservableInputStream.Observer.data(int) with the given arguments.
      Parameters:
      pDataByte - Passed to the observers.
      Throws:
      IOException - Some observer has thrown an exception, which is being passed down.

    • noteError

      protected void noteError(IOException pException) throws IOException
      Notifies the observers by invoking ObservableInputStream.Observer.error(IOException) with the given argument.
      Parameters:
      pException - Passed to the observers.
      Throws:
      IOException - Some observer has thrown an exception, which is being passed down. This may be the same exception, which has been passed as an argument.

    • noteClosed

      protected void noteClosed() throws IOException
      Notifies the observers by invoking ObservableInputStream.Observer.finished().
      Throws:
      IOException - Some observer has thrown an exception, which is being passed down.

    • getObservers

      protected List<ObservableInputStream.Observer> getObservers()
      Gets all currently registered observers.
      Returns:
      a list of the currently registered observers

    • close

      public void close() throws IOException
      Description copied from class: ProxyInputStream
      Invokes the delegate's close() method.
      Specified by:
      close in interface AutoCloseable
      Specified by:
      close in interface Closeable
      Overrides:
      close in class ProxyInputStream
      Throws:
      IOException - if an I/O error occurs

    • consume

      public void consume() throws IOException
      Reads all data from the underlying InputStream, while notifying the observers.
      Throws:
      IOException - The underlying InputStream, or either of the observers has thrown an exception.