Package org.gnome.gio

Class InputStream

java.lang.Object

org.javagi.base.ProxyInstance

org.gnome.gobject.TypeInstance

org.gnome.gobject.GObject

org.gnome.gio.InputStream

All Implemented Interfaces:

AutoCloseable, Proxy, AutoCloseable

Direct Known Subclasses:

FileInputStream, FilterInputStream, InputStream.InputStream$Impl, MemoryInputStream, PollableInputStream.PollableInputStream$Impl

@Generated("io.github.jwharm.JavaGI")
public abstract class InputStream
extends GObject
implements AutoCloseable

GInputStream is a base class for implementing streaming input.

It has functions to read from a stream (read(org.javagi.base.Out<byte[]>, org.gnome.gio.Cancellable)), to close a stream (close(org.gnome.gio.Cancellable)) and to skip some content (skip(long, org.gnome.gio.Cancellable)).

To copy the content of an input stream to an output stream without manually handling the reads and writes, use OutputStream.splice(org.gnome.gio.InputStream, java.util.Set<org.gnome.gio.OutputStreamSpliceFlags>, org.gnome.gio.Cancellable).

See the documentation for IOStream for details of thread safety of streaming APIs.

All of these functions have async variants too.

Nested Class Summary

Nested Classes

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

Nested classes/interfaces inherited from class org.gnome.gobject.GObject

GObject.NotifyCallback, GObject.ObjectClass

Constructor Summary

Constructors

Constructor	Description
InputStream()	Creates a new InputStream.
InputStream(MemorySegment address)	Create a InputStream proxy instance for the provided memory address.

Method Summary

Modifier and Type	Method	Description
protected InputStream	asParent()	Returns 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 closes of the stream, releasing resources related to it.
boolean	closeFinish(AsyncResult result)	Finishes closing a stream asynchronously, started from g_input_stream_close_async().
protected boolean	closeFn(@Nullable Cancellable cancellable)
static MemoryLayout	getMemoryLayout()	The memory layout of the native struct.
static @Nullable Type	getType()	Get the GType of the InputStream class
boolean	hasPending()	Checks if an input stream has pending actions.
boolean	isClosed()	Checks if an input stream is closed.
long	read(@Nullable Out<byte[]> buffer, @Nullable Cancellable cancellable)	Tries to read count bytes from the stream into the buffer starting at buffer. Will block during this read.
boolean	readAll(@Nullable Out<byte[]> buffer, Out<Long> bytesRead, @Nullable Cancellable cancellable)	Tries to read count bytes from the stream into the buffer starting at buffer. Will block during this read.
void	readAllAsync(@Nullable Out<byte[]> buffer, int ioPriority, @Nullable Cancellable cancellable, @Nullable AsyncReadyCallback callback)	Request an asynchronous read of count bytes from the stream into the buffer starting at buffer.
boolean	readAllFinish(AsyncResult result, Out<Long> bytesRead)	Finishes an asynchronous stream read operation started with readAllAsync(org.javagi.base.Out<byte[]>, int, org.gnome.gio.Cancellable, org.gnome.gio.AsyncReadyCallback).
void	readAsync(@Nullable Out<byte[]> buffer, int ioPriority, @Nullable Cancellable cancellable, @Nullable AsyncReadyCallback callback)	Request an asynchronous read of count bytes from the stream into the buffer starting at buffer. When the operation is finished callback will be called.
byte[]	readBytes(long count, @Nullable Cancellable cancellable)	Like g_input_stream_read(), this tries to read count bytes from the stream in a blocking fashion.
void	readBytesAsync(long count, int ioPriority, @Nullable Cancellable cancellable, @Nullable AsyncReadyCallback callback)	Request an asynchronous read of count bytes from the stream into a new GBytes.
byte[]	readBytesFinish(AsyncResult result)	Finishes an asynchronous stream read-into-GBytes operation.
long	readFinish(AsyncResult result)	Finishes an asynchronous stream read operation.
protected long	readFn(@Nullable MemorySegment buffer, long count, @Nullable Cancellable cancellable)
boolean	setPending()	Sets this InputStream to have actions pending.
long	skip(long count, @Nullable Cancellable cancellable)	Tries to skip count bytes from the stream.
void	skipAsync(long count, int ioPriority, @Nullable Cancellable cancellable, @Nullable AsyncReadyCallback callback)	Request an asynchronous skip of count bytes from the stream.
long	skipFinish(AsyncResult result)	Finishes a stream skip operation.

Methods inherited from class org.gnome.gobject.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 org.gnome.gobject.TypeInstance

callParent, callParent, cast, getPrivate, readGClass, writeGClass

Methods inherited from class org.javagi.base.ProxyInstance

equals, handle, hashCode

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.javagi.gio.AutoCloseable

close

Constructor Details

InputStream

public InputStream(MemorySegment address)

Create a InputStream proxy instance for the provided memory address.

Parameters:

address - the memory address of the native object

InputStream

public InputStream()

Creates a new InputStream.

Method Details

getType

public static @Nullable Type getType()

Get the GType of the InputStream class

Returns:

the GType

getMemoryLayout

public static MemoryLayout getMemoryLayout()

The memory layout of the native struct.

Returns:

the memory layout

asParent

protected InputStream asParent()

Returns this instance as if it were its parent type. This is mostly synonymous to the Java super keyword, but will set the native typeclass function pointers to the parent type. When overriding a native virtual method in Java, "chaining up" with super.methodName() doesn't work, because it invokes the overridden function pointer again. To chain up, call asParent().methodName(). This will call the native function pointer of this virtual method in the typeclass of the parent type.

Overrides:

asParent in class GObject

clearPending

public void clearPending()

Clears the pending flag on stream.

close

public boolean close(@Nullable Cancellable cancellable)
              throws GErrorException

Closes the stream, releasing resources related to it.

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

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.

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.

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

closeAsync

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

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

For behaviour details see g_input_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 I/O priority of the request

cancellable - optional cancellable object

callback - a GAsyncReadyCallback to call when the request is satisfied

closeFinish

public boolean closeFinish(AsyncResult result)
                    throws GErrorException

Finishes closing a stream asynchronously, started from g_input_stream_close_async().

Parameters:

result - a GAsyncResult.

Returns:

true if the stream was closed successfully.

Throws:

GErrorException - see GError

hasPending

public boolean hasPending()

Checks if an input stream has pending actions.

Returns:

true if this InputStream has pending actions.

isClosed

public boolean isClosed()

Checks if an input stream is closed.

Returns:

true if the stream is closed.

read

public long read(@Nullable Out<byte[]> buffer,
 @Nullable Cancellable cancellable)
          throws GErrorException

Tries to read count bytes from the stream into the buffer starting at buffer. Will block during this read.

If count is zero returns zero and does nothing. A value of count larger than G_MAXSSIZE will cause a IOErrorEnum.INVALID_ARGUMENT error.

On success, the number of bytes read into the buffer is returned. It is not an error if this is not the same as the requested size, as it can happen e.g. near the end of a file. Zero is returned on end of file (or if count is zero), but never otherwise.

The returned buffer is not a nul-terminated string, it can contain nul bytes at any position, and this function doesn't nul-terminate the buffer.

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. If an operation was partially finished when the operation was cancelled the partial result will be returned, without an error.

On error -1 is returned and error is set accordingly.

Parameters:

buffer - a buffer to read data into (which should be at least count bytes long).

cancellable - optional GCancellable object, null to ignore.

Returns:

Number of bytes read, or -1 on error, or 0 on end of file.

Throws:

GErrorException - see GError

readAll

public boolean readAll(@Nullable Out<byte[]> buffer,
 Out<Long> bytesRead,
 @Nullable Cancellable cancellable)
                throws GErrorException

Tries to read count bytes from the stream into the buffer starting at buffer. Will block during this read.

This function is similar to g_input_stream_read(), except it tries to read as many bytes as requested, only stopping on an error or end of stream.

On a successful read of count bytes, or if we reached the end of the stream, true is returned, and bytesRead is set to the number of bytes read into buffer.

If there is an error during the operation false is returned and error is set to indicate the error status.

As a special exception to the normal conventions for functions that use GError, if this function returns false (and sets error) then bytesRead will be set to the number of bytes that were successfully read before the error was encountered. This functionality is only available from C. If you need it from another language then you must write your own loop around g_input_stream_read().

Parameters:

buffer - a buffer to read data into (which should be at least count bytes long).

bytesRead - location to store the number of bytes that was read from the stream

cancellable - optional GCancellable object, null to ignore.

Returns:

true on success, false if there was an error

Throws:

GErrorException - see GError

readAllAsync

public void readAllAsync(@Nullable Out<byte[]> buffer,
 int ioPriority,
 @Nullable Cancellable cancellable,
 @Nullable AsyncReadyCallback callback)

Request an asynchronous read of count bytes from the stream into the buffer starting at buffer.

This is the asynchronous equivalent of readAll(org.javagi.base.Out<byte[]>, org.javagi.base.Out<java.lang.Long>, org.gnome.gio.Cancellable).

Call readAllFinish(org.gnome.gio.AsyncResult, org.javagi.base.Out<java.lang.Long>) to collect the result.

Any outstanding I/O request with higher priority (lower numerical value) will be executed before an outstanding request with lower priority. Default priority is G_PRIORITY_DEFAULT.

Parameters:

buffer - a buffer to read data into (which should be at least count bytes long)

ioPriority - the I/O priority of the request

cancellable - optional GCancellable object, null to ignore

callback - a GAsyncReadyCallback to call when the request is satisfied

Since:

2.44

readAllFinish

public boolean readAllFinish(AsyncResult result,
 Out<Long> bytesRead)
                      throws GErrorException

Finishes an asynchronous stream read operation started with readAllAsync(org.javagi.base.Out<byte[]>, int, org.gnome.gio.Cancellable, org.gnome.gio.AsyncReadyCallback).

As a special exception to the normal conventions for functions that use GError, if this function returns false (and sets error) then bytesRead will be set to the number of bytes that were successfully read before the error was encountered. This functionality is only available from C. If you need it from another language then you must write your own loop around g_input_stream_read_async().

Parameters:

result - a GAsyncResult

bytesRead - location to store the number of bytes that was read from the stream

Returns:

true on success, false if there was an error

Throws:

GErrorException - see GError

Since:

2.44

readAsync

public void readAsync(@Nullable Out<byte[]> buffer,
 int ioPriority,
 @Nullable Cancellable cancellable,
 @Nullable AsyncReadyCallback callback)

Request an asynchronous read of count bytes from the stream into the buffer starting at buffer. When the operation is finished callback will be called. You can then call g_input_stream_read_finish() to get the result of the operation.

During an async request no other sync and async calls are allowed on stream, and will result in IOErrorEnum.PENDING errors.

A value of count larger than G_MAXSSIZE will cause a IOErrorEnum.INVALID_ARGUMENT error.

On success, the number of bytes read into the buffer will be passed to the callback. It is not an error if this is not the same as the requested size, as it can happen e.g. near the end of a file, but generally we try to read as many bytes as requested. Zero is returned on end of file (or if count is zero), but never otherwise.

Any outstanding i/o request with higher priority (lower numerical value) will be executed before an outstanding request with lower priority. Default priority is G_PRIORITY_DEFAULT.

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:

buffer - a buffer to read data into (which should be at least count bytes long).

ioPriority - the I/O priority of the request.

cancellable - optional GCancellable object, null to ignore.

callback - a GAsyncReadyCallback to call when the request is satisfied

readBytes

public byte[] readBytes(long count,
 @Nullable Cancellable cancellable)
                 throws GErrorException

Like g_input_stream_read(), this tries to read count bytes from the stream in a blocking fashion. However, rather than reading into a user-supplied buffer, this will create a new GBytes containing the data that was read. This may be easier to use from language bindings.

If count is zero, returns a zero-length GBytes and does nothing. A value of count larger than G_MAXSSIZE will cause a IOErrorEnum.INVALID_ARGUMENT error.

On success, a new GBytes is returned. It is not an error if the size of this object is not the same as the requested size, as it can happen e.g. near the end of a file. A zero-length GBytes is returned on end of file (or if count is zero), but never otherwise.

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. If an operation was partially finished when the operation was cancelled the partial result will be returned, without an error.

On error null is returned and error is set accordingly.

Parameters:

count - maximum number of bytes that will be read from the stream. Common values include 4096 and 8192.

cancellable - optional GCancellable object, null to ignore.

Returns:

a new GBytes, or null on error

Throws:

GErrorException - see GError

Since:

2.34

readBytesAsync

public void readBytesAsync(long count,
 int ioPriority,
 @Nullable Cancellable cancellable,
 @Nullable AsyncReadyCallback callback)

Request an asynchronous read of count bytes from the stream into a new GBytes. When the operation is finished callback will be called. You can then call g_input_stream_read_bytes_finish() to get the result of the operation.

During an async request no other sync and async calls are allowed on stream, and will result in IOErrorEnum.PENDING errors.

A value of count larger than G_MAXSSIZE will cause a IOErrorEnum.INVALID_ARGUMENT error.

On success, the new GBytes will be passed to the callback. It is not an error if this is smaller than the requested size, as it can happen e.g. near the end of a file, but generally we try to read as many bytes as requested. Zero is returned on end of file (or if count is zero), but never otherwise.

Any outstanding I/O request with higher priority (lower numerical value) will be executed before an outstanding request with lower priority. Default priority is G_PRIORITY_DEFAULT.

Parameters:

count - the number of bytes that will be read from the stream

ioPriority - the I/O priority of the request

cancellable - optional GCancellable object, null to ignore.

callback - a GAsyncReadyCallback to call when the request is satisfied

Since:

2.34

readBytesFinish

public byte[] readBytesFinish(AsyncResult result)
                       throws GErrorException

Finishes an asynchronous stream read-into-GBytes operation.

Parameters:

result - a GAsyncResult.

Returns:

the newly-allocated GBytes, or null on error

Throws:

GErrorException - see GError

Since:

2.34

readFinish

public long readFinish(AsyncResult result)
                throws GErrorException

Finishes an asynchronous stream read operation.

Parameters:

result - a GAsyncResult.

Returns:

number of bytes read in, or -1 on error, or 0 on end of file.

Throws:

GErrorException - see GError

setPending

public boolean setPending()
                   throws GErrorException

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

Returns:

true if pending was previously unset and is now set.

Throws:

GErrorException - see GError

skip

public long skip(long count,
 @Nullable Cancellable cancellable)
          throws GErrorException

Tries to skip count bytes from the stream. Will block during the operation.

This is identical to g_input_stream_read(), from a behaviour standpoint, but the bytes that are skipped are not returned to the user. Some streams have an implementation that is more efficient than reading the data.

This function is optional for inherited classes, as the default implementation emulates it using read.

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. If an operation was partially finished when the operation was cancelled the partial result will be returned, without an error.

Parameters:

count - the number of bytes that will be skipped from the stream

cancellable - optional GCancellable object, null to ignore.

Returns:

Number of bytes skipped, or -1 on error

Throws:

GErrorException - see GError

skipAsync

public void skipAsync(long count,
 int ioPriority,
 @Nullable Cancellable cancellable,
 @Nullable AsyncReadyCallback callback)

Request an asynchronous skip of count bytes from the stream. When the operation is finished callback will be called. You can then call g_input_stream_skip_finish() to get the result of the operation.

During an async request no other sync and async calls are allowed, and will result in IOErrorEnum.PENDING errors.

A value of count larger than G_MAXSSIZE will cause a IOErrorEnum.INVALID_ARGUMENT error.

On success, the number of bytes skipped will be passed to the callback. It is not an error if this is not the same as the requested size, as it can happen e.g. near the end of a file, but generally we try to skip as many bytes as requested. Zero is returned on end of file (or if count is zero), but never otherwise.

Any outstanding i/o request with higher priority (lower numerical value) will be executed before an outstanding request with lower priority. Default priority is G_PRIORITY_DEFAULT.

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:

count - the number of bytes that will be skipped from the stream

ioPriority - the I/O priority of the request

cancellable - optional GCancellable object, null to ignore.

callback - a GAsyncReadyCallback to call when the request is satisfied

skipFinish

public long skipFinish(AsyncResult result)
                throws GErrorException

Finishes a stream skip operation.

Parameters:

result - a GAsyncResult.

Returns:

the size of the bytes skipped, or -1 on error.

Throws:

GErrorException - see GError

closeFn

protected boolean closeFn(@Nullable Cancellable cancellable)
                   throws GErrorException

Throws:

GErrorException

readFn

protected long readFn(@Nullable MemorySegment buffer,
 long count,
 @Nullable Cancellable cancellable)
               throws GErrorException

Throws:

GErrorException