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Préférences
Moteurs de recherche
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JavaTM 2 Platform Std. Ed. v1.6.0
javax.imageio.stream
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Field Summary |
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Fields inherited from class javax.imageio.stream.ImageInputStreamImpl |
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bitOffset, byteOrder, flushedPos, streamPos |
Constructor Summary | |
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FileCacheImageInputStream(InputStream stream,
File cacheDir)
Constructs a FileCacheImageInputStream that will read
from a given InputStream . |
Method Summary | |
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void |
close()
Closes this FileCacheImageInputStream , closing
and removing the cache file. |
protected void |
finalize()
Finalizes this object prior to garbage collection. |
boolean |
isCached()
Returns true since this
ImageInputStream caches data in order to allow
seeking backwards. |
boolean |
isCachedFile()
Returns true since this
ImageInputStream maintains a file cache. |
boolean |
isCachedMemory()
Returns false since this
ImageInputStream does not maintain a main memory
cache. |
int |
read()
Reads a single byte from the stream and returns it as an int between 0 and 255. |
int |
read(byte[] b,
int off,
int len)
Reads up to len bytes from the stream, and stores
them into b starting at index off . |
Methods inherited from class javax.imageio.stream.ImageInputStreamImpl |
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checkClosed, flush, flushBefore, getBitOffset, getByteOrder, getFlushedPosition, getStreamPosition, length, 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, seek, setBitOffset, setByteOrder, skipBytes, skipBytes |
Methods inherited from class java.lang.Object |
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clone, equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
Constructor Detail |
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public FileCacheImageInputStream(InputStream stream, File cacheDir) throws IOException
FileCacheImageInputStream
that will read
from a given InputStream
.
A temporary file is used as a cache. If
cacheDir
is non-null
and is a
directory, the file will be created there. If it is
null
, the system-dependent default temporary-file
directory will be used (see the documentation for
File.createTempFile
for details).
stream
- an InputStream
to read from.cacheDir
- a File
indicating where the
cache file should be created, or null
to use the
system directory.
IllegalArgumentException
- if stream
is
null
.
IllegalArgumentException
- if cacheDir
is
non-null
but is not a directory.
IOException
- if a cache file cannot be created.Method Detail |
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public int read() throws IOException
ImageInputStreamImpl
int
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.
read
in interface ImageInputStream
read
in class ImageInputStreamImpl
-1
if EOF is reached.
IOException
- if the stream has been closed.public int read(byte[] b, int off, int len) throws IOException
ImageInputStreamImpl
len
bytes from the stream, and stores
them into b
starting at index off
.
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.
read
in interface ImageInputStream
read
in class ImageInputStreamImpl
b
- an array of bytes to be written to.off
- the starting position within b
to write to.len
- the maximum number of bytes to read.
-1
to indicate EOF.
IOException
- if an I/O error occurs.public boolean isCached()
true
since this
ImageInputStream
caches data in order to allow
seeking backwards.
isCached
in interface ImageInputStream
isCached
in class ImageInputStreamImpl
true
.isCachedMemory()
,
isCachedFile()
public boolean isCachedFile()
true
since this
ImageInputStream
maintains a file cache.
isCachedFile
in interface ImageInputStream
isCachedFile
in class ImageInputStreamImpl
true
.isCached()
,
isCachedMemory()
public boolean isCachedMemory()
false
since this
ImageInputStream
does not maintain a main memory
cache.
isCachedMemory
in interface ImageInputStream
isCachedMemory
in class ImageInputStreamImpl
false
.isCached()
,
isCachedFile()
public void close() throws IOException
FileCacheImageInputStream
, closing
and removing the cache file. The source InputStream
is not closed.
close
in interface ImageInputStream
close
in class ImageInputStreamImpl
IOException
- if an error occurs.protected void finalize() throws Throwable
close
method is called to close any open input
source. This method should not be called from application
code.
finalize
in class ImageInputStreamImpl
Throwable
- if an error occurs during superclass
finalization.