Class IOStream

java.lang.Object

org.javagi.base.ProxyInstance

org.gnome.gobject.TypeInstance

org.gnome.gobject.GObject

org.gnome.gio.IOStream

All Implemented Interfaces:

AutoCloseable, Proxy, AutoCloseable

Direct Known Subclasses:

FileIOStream, IOStream.IOStream$Impl, SimpleIOStream, SocketConnection, TlsConnection

@Generated("org.javagi.JavaGI")
public abstract class IOStream
extends GObject
implements AutoCloseable

GIOStream represents an object that has both read and write streams. Generally the two streams act as separate input and output streams, but they share some common resources and state. For instance, for seekable streams, both streams may use the same position.

Examples of GIOStream objects are SocketConnection, which represents a two-way network connection; and FileIOStream, which represents a file handle opened in read-write mode.

To do the actual reading and writing you need to get the substreams with getInputStream() and getOutputStream().

The GIOStream object owns the input and the output streams, not the other way around, so keeping the substreams alive will not keep the GIOStream object alive. If the GIOStream object is freed it will be closed, thus closing the substreams, so even if the substreams stay alive they will always return G_IO_ERROR_CLOSED for all operations.

To close a stream use close(Cancellable) which will close the common stream object and also the individual substreams. You can also close the substreams themselves. In most cases this only marks the substream as closed, so further I/O on it fails but common state in the GIOStream may still be open. However, some streams may support ‘half-closed’ states where one direction of the stream is actually shut down.

Operations on GIOStreams cannot be started while another operation on the GIOStream or its substreams is in progress. Specifically, an application can read from the InputStream and write to the OutputStream simultaneously (either in separate threads, or as asynchronous operations in the same thread), but an application cannot start any GIOStream operation while there is a GIOStream, GInputStream or GOutputStream operation in progress, and an application can’t start any GInputStream or GOutputStream operation while there is a GIOStream operation in progress.

This is a product of individual stream operations being associated with a given GLib.MainContext (the thread-default context at the time the operation was started), rather than entire streams being associated with a single GMainContext.

GIO may run operations on GIOStreams from other (worker) threads, and this may be exposed to application code in the behaviour of wrapper streams, such as BufferedInputStream or TlsConnection. With such wrapper APIs, application code may only run operations on the base (wrapped) stream when the wrapper stream is idle. Note that the semantics of such operations may not be well-defined due to the state the wrapper stream leaves the base stream in (though they are guaranteed not to crash).

Since:

2.22

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	IOStream.Builder<B extends IOStream.Builder<B>>	Inner class implementing a builder pattern to construct a GObject with properties.
static class	IOStream.IOStream$Impl	The IOStream$Impl type represents a native instance of the abstract IOStream class.
static class	IOStream.IOStreamClass

Nested classes/interfaces inherited from class GObject

GObject.NotifyCallback, GObject.ObjectClass

Constructor Summary

Constructors

Constructor	Description
IOStream()	Create a new IOStream.
IOStream(MemorySegment address)	Create a IOStream instance for the provided memory address.

Method Summary

Modifier and Type	Method	Description
protected IOStream	asParent()	Return this instance as if it were its parent type.
void	clearPending()	Clears the pending flag on stream.
boolean	close(@Nullable Cancellable cancellable)	Closes the stream, releasing resources related to it.
void	closeAsync(int ioPriority, @Nullable Cancellable cancellable, @Nullable AsyncReadyCallback callback)	Requests an asynchronous close of the stream, releasing resources related to it.
boolean	closeFinish(AsyncResult result)	Closes a stream.
protected boolean	closeFn(@Nullable Cancellable cancellable)
InputStream	getInputStream()	Gets the input stream for this object.
static MemoryLayout	getMemoryLayout()	The memory layout of the native struct.
OutputStream	getOutputStream()	Gets the output stream for this object.
static @Nullable Type	getType()	Get the GType of the IOStream class.
boolean	hasPending()	Checks if a stream has pending actions.
boolean	isClosed()	Checks if a stream is closed.
boolean	setPending()	Sets this IOStream to have actions pending.
void	spliceAsync(IOStream stream2, Set<IOStreamSpliceFlags> flags, int ioPriority, @Nullable Cancellable cancellable, @Nullable AsyncReadyCallback callback)	Asynchronously splice the output stream of this IOStream to the input stream of stream2, and splice the output stream of stream2 to the input stream of stream1.
void	spliceAsync(IOStream stream2, IOStreamSpliceFlags flags, int ioPriority, @Nullable Cancellable cancellable, @Nullable AsyncReadyCallback callback)	Asynchronously splice the output stream of this IOStream to the input stream of stream2, and splice the output stream of stream2 to the input stream of stream1.
static boolean	spliceFinish(AsyncResult result)	Finishes an asynchronous io stream splice operation.

Methods inherited from class GObject

addToggleRef, addWeakPointer, bindProperty, bindProperty, bindProperty, bindPropertyFull, bindPropertyFull, bindPropertyWithClosures, bindPropertyWithClosures, builder, compatControl, connect, connect, connect, constructed, disconnect, dispatchPropertiesChanged, dispose, dupData, dupQdata, emit, emitNotify, finalize_, forceFloating, freezeNotify, get, getData, getProperty, getProperty, getProperty, getQdata, getv, interfaceFindProperty, interfaceInstallProperty, interfaceListProperties, isFloating, newInstance, newInstance, newv, notify, notify, notifyByPspec, onNotify, ref, refSink, removeToggleRef, removeWeakPointer, replaceData, replaceQdata, runDispose, set, setData, setDataFull, setProperty, setProperty, setProperty, setQdata, setQdataFull, setv, stealData, stealQdata, takeRef, thawNotify, unref, watchClosure, weakRef, weakUnref, withProperties

Methods inherited from class TypeInstance

callParent, callParent, cast, getPrivate, readGClass, writeGClass

Methods inherited from class ProxyInstance

equals, handle, hashCode

Methods inherited from class Object

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

Methods inherited from interface AutoCloseable

close

Constructor Details

IOStream

public IOStream(MemorySegment address)

Create a IOStream instance for the provided memory address.

Parameters:

address - the memory address of the native object

IOStream

public IOStream()

Create a new IOStream.

Method Details

getType

public static @Nullable Type getType()

Get the GType of the IOStream class.

Returns:

the GType

getMemoryLayout

public static MemoryLayout getMemoryLayout()

The memory layout of the native struct.

Returns:

the memory layout

asParent

protected IOStream asParent()

Return this instance as if it were its parent type. Comparable to the Java super keyword, but ensures the parent typeclass is also used in native code.

Overrides:

asParent in class GObject

Returns:

the instance as if it were its parent type

spliceFinish

public static boolean spliceFinish(AsyncResult result)
                            throws GErrorException

Finishes an asynchronous io stream splice operation.

Parameters:

result - a GAsyncResult.

Returns:

true on success, false otherwise.

Throws:

GErrorException - see GError

Since:

2.28

clearPending

public void clearPending()

Clears the pending flag on stream.

Since:

2.22

close

public boolean close(@Nullable Cancellable cancellable)
              throws GErrorException

Closes the stream, releasing resources related to it. This will also close the individual input and output streams, if they are not already closed.

Once the stream is closed, all other operations will return IOErrorEnum.CLOSED. Closing a stream multiple times will not return an error.

Closing a stream will automatically flush any outstanding buffers in the stream.

Streams will be automatically closed when the last reference is dropped, but you might want to call this function to make sure resources are released as early as possible.

Some streams might keep the backing store of the stream (e.g. a file descriptor) open after the stream is closed. See the documentation for the individual stream for details.

On failure the first error that happened will be reported, but the close operation will finish as much as possible. A stream that failed to close will still return IOErrorEnum.CLOSED for all operations. Still, it is important to check and report the error to the user, otherwise there might be a loss of data as all data might not be written.

If cancellable is not NULL, then the operation can be cancelled by triggering the cancellable object from another thread. If the operation was cancelled, the error IOErrorEnum.CANCELLED will be returned. Cancelling a close will still leave the stream closed, but some streams can use a faster close that doesn't block to e.g. check errors.

The default implementation of this method just calls close on the individual input/output streams.

Specified by:

close in interface AutoCloseable

Parameters:

cancellable - optional GCancellable object, null to ignore

Returns:

true on success, false on failure

Throws:

GErrorException - see GError

Since:

2.22

closeAsync

public void closeAsync(int ioPriority,
 @Nullable Cancellable cancellable,
 @Nullable AsyncReadyCallback callback)

Requests an asynchronous close of the stream, releasing resources related to it. When the operation is finished callback will be called. You can then call g_io_stream_close_finish() to get the result of the operation.

For behaviour details see g_io_stream_close().

The asynchronous methods have a default fallback that uses threads to implement asynchronicity, so they are optional for inheriting classes. However, if you override one you must override all.

Parameters:

ioPriority - the io priority of the request

cancellable - optional cancellable object

callback - a GAsyncReadyCallback to call when the request is satisfied

Since:

2.22

closeFinish

public boolean closeFinish(AsyncResult result)
                    throws GErrorException

Closes a stream.

Parameters:

result - a GAsyncResult

Returns:

true if stream was successfully closed, false otherwise.

Throws:

GErrorException - see GError

Since:

2.22

getInputStream

public InputStream getInputStream()

Gets the input stream for this object. This is used for reading.

Returns:

a GInputStream, owned by the GIOStream. Do not free.

Since:

2.22

getOutputStream

public OutputStream getOutputStream()

Gets the output stream for this object. This is used for writing.

Returns:

a GOutputStream, owned by the GIOStream. Do not free.

Since:

2.22

hasPending

public boolean hasPending()

Checks if a stream has pending actions.

Returns:

true if this IOStream has pending actions.

Since:

2.22

isClosed

public boolean isClosed()

Checks if a stream is closed.

Returns:

true if the stream is closed.

Since:

2.22

setPending

public boolean setPending()
                   throws GErrorException

Sets this IOStream to have actions pending. If the pending flag is already set or this IOStream is closed, it will return false and set error.

Returns:

true if pending was previously unset and is now set.

Throws:

GErrorException - see GError

Since:

2.22

spliceAsync

public void spliceAsync(IOStream stream2,
 Set<IOStreamSpliceFlags> flags,
 int ioPriority,
 @Nullable Cancellable cancellable,
 @Nullable AsyncReadyCallback callback)

Asynchronously splice the output stream of this IOStream to the input stream of stream2, and splice the output stream of stream2 to the input stream of stream1.

When the operation is finished callback will be called. You can then call g_io_stream_splice_finish() to get the result of the operation.

Parameters:

stream2 - a GIOStream.

flags - a set of GIOStreamSpliceFlags.

ioPriority - the io priority of the request.

cancellable - optional GCancellable object, null to ignore.

callback - a GAsyncReadyCallback to call when the request is satisfied

Since:

2.28

spliceAsync

public void spliceAsync(IOStream stream2,
 IOStreamSpliceFlags flags,
 int ioPriority,
 @Nullable Cancellable cancellable,
 @Nullable AsyncReadyCallback callback)

Asynchronously splice the output stream of this IOStream to the input stream of stream2, and splice the output stream of stream2 to the input stream of stream1.

When the operation is finished callback will be called. You can then call g_io_stream_splice_finish() to get the result of the operation.

Parameters:

stream2 - a GIOStream.

flags - a set of GIOStreamSpliceFlags.

ioPriority - the io priority of the request.

cancellable - optional GCancellable object, null to ignore.

callback - a GAsyncReadyCallback to call when the request is satisfied

Since:

2.28

closeFn

protected boolean closeFn(@Nullable Cancellable cancellable)
                   throws GErrorException

Throws:

GErrorException