- java.lang.Object
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- javax.imageio.stream.ImageInputStreamImpl
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- javax.imageio.stream.FileImageInputStream
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- All Implemented Interfaces:
- Closeable, DataInput, AutoCloseable, ImageInputStream
public class FileImageInputStream extends ImageInputStreamImpl
An implementation ofImageInputStream
that gets its input from aFile
orRandomAccessFile
. The file contents are assumed to be stable during the lifetime of the object.
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Field Summary
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Fields inherited from class javax.imageio.stream.ImageInputStreamImpl
bitOffset, byteOrder, flushedPos, streamPos
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Constructor Summary
Constructors Constructor and Description FileImageInputStream(File f)
Constructs aFileImageInputStream
that will read from a givenFile
.FileImageInputStream(RandomAccessFile raf)
Constructs aFileImageInputStream
that will read from a givenRandomAccessFile
.
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Method Summary
Methods Modifier and Type Method and Description void
close()
Closes the stream.protected void
finalize()
Finalizes this object prior to garbage collection.long
length()
Returns the length of the underlying file, or-1
if it is unknown.int
read()
Reads a single byte from the stream and returns it as anint
between 0 and 255.int
read(byte[] b, int off, int len)
Reads up tolen
bytes from the stream, and stores them intob
starting at indexoff
.void
seek(long pos)
Sets the current stream position to the desired location.-
Methods inherited from class javax.imageio.stream.ImageInputStreamImpl
checkClosed, flush, flushBefore, getBitOffset, getByteOrder, getFlushedPosition, getStreamPosition, isCached, isCachedFile, isCachedMemory, mark, read, readBit, readBits, readBoolean, readByte, readBytes, readChar, readDouble, readFloat, readFully, readFully, readFully, readFully, readFully, readFully, readFully, readFully, readInt, readLine, readLong, readShort, readUnsignedByte, readUnsignedInt, readUnsignedShort, readUTF, reset, setBitOffset, setByteOrder, skipBytes, skipBytes
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Constructor Detail
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FileImageInputStream
public FileImageInputStream(File f) throws FileNotFoundException, IOException
Constructs aFileImageInputStream
that will read from a givenFile
.The file contents must not change between the time this object is constructed and the time of the last call to a read method.
- Parameters:
f
- aFile
to read from.- Throws:
IllegalArgumentException
- iff
isnull
.SecurityException
- if a security manager exists and does not allow read access to the file.FileNotFoundException
- iff
is a directory or cannot be opened for reading for any other reason.IOException
- if an I/O error occurs.
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FileImageInputStream
public FileImageInputStream(RandomAccessFile raf)
Constructs aFileImageInputStream
that will read from a givenRandomAccessFile
.The file contents must not change between the time this object is constructed and the time of the last call to a read method.
- Parameters:
raf
- aRandomAccessFile
to read from.- Throws:
IllegalArgumentException
- ifraf
isnull
.
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Method Detail
-
read
public int read() throws IOException
Description copied from class:ImageInputStreamImpl
Reads a single byte from the stream and returns it as anint
between 0 and 255. If EOF is reached,-1
is returned.Subclasses must provide an implementation for this method. The subclass implementation should update the stream position before exiting.
The bit offset within the stream must be reset to zero before the read occurs.
- Specified by:
read
in interfaceImageInputStream
- Specified by:
read
in classImageInputStreamImpl
- Returns:
- the value of the next byte in the stream, or
-1
if EOF is reached. - Throws:
IOException
- if the stream has been closed.
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read
public int read(byte[] b, int off, int len) throws IOException
Description copied from class:ImageInputStreamImpl
Reads up tolen
bytes from the stream, and stores them intob
starting at indexoff
. If no bytes can be read because the end of the stream has been reached,-1
is returned.The bit offset within the stream must be reset to zero before the read occurs.
Subclasses must provide an implementation for this method. The subclass implementation should update the stream position before exiting.
- Specified by:
read
in interfaceImageInputStream
- Specified by:
read
in classImageInputStreamImpl
- Parameters:
b
- an array of bytes to be written to.off
- the starting position withinb
to write to.len
- the maximum number of bytes to read.- Returns:
- the number of bytes actually read, or
-1
to indicate EOF. - Throws:
IOException
- if an I/O error occurs.
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length
public long length()
Returns the length of the underlying file, or-1
if it is unknown.- Specified by:
length
in interfaceImageInputStream
- Overrides:
length
in classImageInputStreamImpl
- Returns:
- the file length as a
long
, or-1
.
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seek
public void seek(long pos) throws IOException
Description copied from interface:ImageInputStream
Sets the current stream position to the desired location. The next read will occur at this location. The bit offset is set to 0.An
IndexOutOfBoundsException
will be thrown ifpos
is smaller than the flushed position (as returned bygetflushedPosition
).It is legal to seek past the end of the file; an
EOFException
will be thrown only if a read is performed.- Specified by:
seek
in interfaceImageInputStream
- Overrides:
seek
in classImageInputStreamImpl
- Parameters:
pos
- along
containing the desired file pointer position.- Throws:
IOException
- if any other I/O error occurs.
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close
public void close() throws IOException
Description copied from interface:ImageInputStream
Closes the stream. Attempts to access a stream that has been closed may result inIOException
s or incorrect behavior. Calling this method may allow classes implementing this interface to release resources associated with the stream such as memory, disk space, or file descriptors.- Specified by:
close
in interfaceCloseable
- Specified by:
close
in interfaceAutoCloseable
- Specified by:
close
in interfaceImageInputStream
- Overrides:
close
in classImageInputStreamImpl
- Throws:
IOException
- if an I/O error occurs.
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finalize
protected void finalize() throws Throwable
Finalizes this object prior to garbage collection. Theclose
method is called to close any open input source. This method should not be called from application code.- Overrides:
finalize
in classImageInputStreamImpl
- Throws:
Throwable
- if an error occurs during superclass finalization.
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Nederlandse vertaling
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Bij voorbaat dank.
Document heeft de 11/06/2005 gemaakt, de laatste keer de 04/03/2020 gewijzigd
Bron van het afgedrukte document:https://www.gaudry.be/nl/java-api-rf-javax/imageio/stream/FileImageInputStream.html
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