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:

MessageDigestCalculatingInputStream

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	ObservableInputStream.Observer	Abstracts observer callback for ObservableInputStreams.

Constructor Summary

Constructors

Constructor	Description
ObservableInputStream(InputStream inputStream)	Creates a new ObservableInputStream for the given InputStream.
ObservableInputStream(InputStream inputStream, ObservableInputStream.Observer... observers)	Creates a new ObservableInputStream for the given InputStream.

Method Summary

Modifier and Type	Method	Description
void	add(ObservableInputStream.Observer observer)	Adds an Observer.
void	close()	Invokes the delegate's close() method.
void	consume()	Reads all data from the underlying InputStream, while notifying the observers.
List<ObservableInputStream.Observer>	getObservers()	Gets all currently registered observers.
int	read()	Invokes the delegate's read() method.
int	read(byte[] buffer)	Invokes the delegate's read(byte[]) method.
int	read(byte[] buffer, int offset, int length)	Invokes the delegate's read(byte[], int, int) method.
void	remove(ObservableInputStream.Observer observer)	Removes an Observer.
void	removeAllObservers()	Removes all Observers.

Methods inherited from class org.apache.commons.io.input.ProxyInputStream

available, mark, markSupported, reset, skip

Methods inherited from class java.io.InputStream

nullInputStream, readAllBytes, readNBytes, readNBytes, transferTo

Methods inherited from class java.lang.Object

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

Constructor Detail

ObservableInputStream

public ObservableInputStream(InputStream inputStream)

Creates a new ObservableInputStream for the given InputStream.

Parameters:

inputStream - the input stream to observe.

ObservableInputStream

public ObservableInputStream(InputStream inputStream,
                             ObservableInputStream.Observer... observers)

Creates a new ObservableInputStream for the given InputStream.

Parameters:

inputStream - the input stream to observe.

observers - List of observer callbacks.

Since:

2.9.0

Method Detail

add

public void add(ObservableInputStream.Observer observer)

Adds an Observer.

Parameters:

observer - the observer to add.

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.

getObservers

public List<ObservableInputStream.Observer> getObservers()

Gets all currently registered observers.

Returns:

a list of the currently registered observers.

Since:

2.9.0

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[] buffer)
         throws IOException

Description copied from class: ProxyInputStream

Invokes the delegate's read(byte[]) method.

Overrides:

read in class ProxyInputStream

Parameters:

buffer - 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[] buffer,
                int offset,
                int length)
         throws IOException

Description copied from class: ProxyInputStream

Invokes the delegate's read(byte[], int, int) method.

Overrides:

read in class ProxyInputStream

Parameters:

buffer - the buffer to read the bytes into

offset - The start offset

length - 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.

remove

public void remove(ObservableInputStream.Observer observer)

Removes an Observer.

Parameters:

observer - the observer to remove

removeAllObservers

public void removeAllObservers()

Removes all Observers.