- java.lang.Object
-
- javax.imageio.stream.ImageInputStreamImpl
-
- javax.imageio.stream.FileCacheImageInputStream
-
- All Implemented Interfaces:
- Closeable, DataInput, AutoCloseable, ImageInputStream
public class FileCacheImageInputStream extends ImageInputStreamImpl
An implementation ofImageInputStream
that gets its input from a regularInputStream
. A file is used to cache previously read data.
-
-
Field Summary
-
Fields inherited from class javax.imageio.stream.ImageInputStreamImpl
bitOffset, byteOrder, flushedPos, streamPos
-
-
Constructor Summary
Constructors Constructor and Description FileCacheImageInputStream(InputStream stream, File cacheDir)
Constructs aFileCacheImageInputStream
that will read from a givenInputStream
.
-
Method Summary
Methods Modifier and Type Method and Description void
close()
Closes thisFileCacheImageInputStream
, closing and removing the cache file.protected void
finalize()
Finalizes this object prior to garbage collection.boolean
isCached()
Returnstrue
since thisImageInputStream
caches data in order to allow seeking backwards.boolean
isCachedFile()
Returnstrue
since thisImageInputStream
maintains a file cache.boolean
isCachedMemory()
Returnsfalse
since thisImageInputStream
does not maintain a main memory cache.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
.-
Methods inherited from class javax.imageio.stream.ImageInputStreamImpl
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
-
-
-
-
Constructor Detail
-
FileCacheImageInputStream
public FileCacheImageInputStream(InputStream stream, File cacheDir) throws IOException
Constructs aFileCacheImageInputStream
that will read from a givenInputStream
.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 isnull
, the system-dependent default temporary-file directory will be used (see the documentation forFile.createTempFile
for details).- Parameters:
stream
- anInputStream
to read from.cacheDir
- aFile
indicating where the cache file should be created, ornull
to use the system directory.- Throws:
IllegalArgumentException
- ifstream
isnull
.IllegalArgumentException
- ifcacheDir
is non-null
but is not a directory.IOException
- if a cache file cannot be created.
-
-
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.
-
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.
-
isCached
public boolean isCached()
Returnstrue
since thisImageInputStream
caches data in order to allow seeking backwards.- Specified by:
isCached
in interfaceImageInputStream
- Overrides:
isCached
in classImageInputStreamImpl
- Returns:
true
.- See Also:
isCachedMemory()
,isCachedFile()
-
isCachedFile
public boolean isCachedFile()
Returnstrue
since thisImageInputStream
maintains a file cache.- Specified by:
isCachedFile
in interfaceImageInputStream
- Overrides:
isCachedFile
in classImageInputStreamImpl
- Returns:
true
.- See Also:
isCached()
,isCachedMemory()
-
isCachedMemory
public boolean isCachedMemory()
Returnsfalse
since thisImageInputStream
does not maintain a main memory cache.- Specified by:
isCachedMemory
in interfaceImageInputStream
- Overrides:
isCachedMemory
in classImageInputStreamImpl
- Returns:
false
.- See Also:
isCached()
,isCachedFile()
-
close
public void close() throws IOException
Closes thisFileCacheImageInputStream
, closing and removing the cache file. The sourceInputStream
is not closed.- Specified by:
close
in interfaceCloseable
- Specified by:
close
in interfaceAutoCloseable
- Specified by:
close
in interfaceImageInputStream
- Overrides:
close
in classImageInputStreamImpl
- Throws:
IOException
- if an error occurs.
-
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.
-
-
Deutsche Übersetzung
Sie haben gebeten, diese Seite auf Deutsch zu besuchen. Momentan ist nur die Oberfläche übersetzt, aber noch nicht der gesamte Inhalt.Wenn Sie mir bei Übersetzungen helfen wollen, ist Ihr Beitrag willkommen. Alles, was Sie tun müssen, ist, sich auf der Website zu registrieren und mir eine Nachricht zu schicken, in der Sie gebeten werden, Sie der Gruppe der Übersetzer hinzuzufügen, die Ihnen die Möglichkeit gibt, die gewünschten Seiten zu übersetzen. Ein Link am Ende jeder übersetzten Seite zeigt an, dass Sie der Übersetzer sind und einen Link zu Ihrem Profil haben.
Vielen Dank im Voraus.
Dokument erstellt 11/06/2005, zuletzt geändert 04/03/2020
Quelle des gedruckten Dokuments:https://www.gaudry.be/de/java-api-rf-javax/imageio/stream/FileCacheImageInputStream.html
Die Infobro ist eine persönliche Seite, deren Inhalt in meiner alleinigen Verantwortung liegt. Der Text ist unter der CreativeCommons-Lizenz (BY-NC-SA) verfügbar. Weitere Informationen auf die Nutzungsbedingungen und dem Autor.
Referenzen
Diese Verweise und Links verweisen auf Dokumente, die während des Schreibens dieser Seite konsultiert wurden, oder die zusätzliche Informationen liefern können, aber die Autoren dieser Quellen können nicht für den Inhalt dieser Seite verantwortlich gemacht werden.
Der Autor Diese Website ist allein dafür verantwortlich, wie die verschiedenen Konzepte und Freiheiten, die mit den Nachschlagewerken gemacht werden, hier dargestellt werden. Denken Sie daran, dass Sie mehrere Quellinformationen austauschen müssen, um das Risiko von Fehlern zu reduzieren.