FileCacheImageInputStream (Java Platform SE 7 ) (original) (raw)

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 of ImageInputStream that gets its input from a regular InputStream. A file is used to cache previously read data.

Field Summary

 * ### Fields inherited from class javax.imageio.stream.[ImageInputStreamImpl](../../../javax/imageio/stream/ImageInputStreamImpl.html "class in javax.imageio.stream")  
 `[bitOffset](../../../javax/imageio/stream/ImageInputStreamImpl.html#bitOffset), [byteOrder](../../../javax/imageio/stream/ImageInputStreamImpl.html#byteOrder), [flushedPos](../../../javax/imageio/stream/ImageInputStreamImpl.html#flushedPos), [streamPos](../../../javax/imageio/stream/ImageInputStreamImpl.html#streamPos)`

Constructor Summary

Constructors

Constructor and Description
FileCacheImageInputStream(InputStream stream,File cacheDir) Constructs a FileCacheImageInputStream that will read from a given InputStream.

Method Summary

Methods

Modifier and Type	Method and Description
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 thisImageInputStream caches data in order to allow seeking backwards.
boolean	isCachedFile() Returns true since thisImageInputStream maintains a file cache.
boolean	isCachedMemory() Returns false 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 to len bytes from the stream, and stores them into b starting at index off.

   * ### Methods inherited from class javax.imageio.stream.[ImageInputStreamImpl](../../../javax/imageio/stream/ImageInputStreamImpl.html "class in javax.imageio.stream")  
   `[checkClosed](../../../javax/imageio/stream/ImageInputStreamImpl.html#checkClosed%28%29), [flush](../../../javax/imageio/stream/ImageInputStreamImpl.html#flush%28%29), [flushBefore](../../../javax/imageio/stream/ImageInputStreamImpl.html#flushBefore%28long%29), [getBitOffset](../../../javax/imageio/stream/ImageInputStreamImpl.html#getBitOffset%28%29), [getByteOrder](../../../javax/imageio/stream/ImageInputStreamImpl.html#getByteOrder%28%29), [getFlushedPosition](../../../javax/imageio/stream/ImageInputStreamImpl.html#getFlushedPosition%28%29), [getStreamPosition](../../../javax/imageio/stream/ImageInputStreamImpl.html#getStreamPosition%28%29), [length](../../../javax/imageio/stream/ImageInputStreamImpl.html#length%28%29), [mark](../../../javax/imageio/stream/ImageInputStreamImpl.html#mark%28%29), [read](../../../javax/imageio/stream/ImageInputStreamImpl.html#read%28byte[]%29), [readBit](../../../javax/imageio/stream/ImageInputStreamImpl.html#readBit%28%29), [readBits](../../../javax/imageio/stream/ImageInputStreamImpl.html#readBits%28int%29), [readBoolean](../../../javax/imageio/stream/ImageInputStreamImpl.html#readBoolean%28%29), [readByte](../../../javax/imageio/stream/ImageInputStreamImpl.html#readByte%28%29), [readBytes](../../../javax/imageio/stream/ImageInputStreamImpl.html#readBytes%28javax.imageio.stream.IIOByteBuffer,%20int%29), [readChar](../../../javax/imageio/stream/ImageInputStreamImpl.html#readChar%28%29), [readDouble](../../../javax/imageio/stream/ImageInputStreamImpl.html#readDouble%28%29), [readFloat](../../../javax/imageio/stream/ImageInputStreamImpl.html#readFloat%28%29), [readFully](../../../javax/imageio/stream/ImageInputStreamImpl.html#readFully%28byte[]%29), [readFully](../../../javax/imageio/stream/ImageInputStreamImpl.html#readFully%28byte[],%20int,%20int%29), [readFully](../../../javax/imageio/stream/ImageInputStreamImpl.html#readFully%28char[],%20int,%20int%29), [readFully](../../../javax/imageio/stream/ImageInputStreamImpl.html#readFully%28double[],%20int,%20int%29), [readFully](../../../javax/imageio/stream/ImageInputStreamImpl.html#readFully%28float[],%20int,%20int%29), [readFully](../../../javax/imageio/stream/ImageInputStreamImpl.html#readFully%28int[],%20int,%20int%29), [readFully](../../../javax/imageio/stream/ImageInputStreamImpl.html#readFully%28long[],%20int,%20int%29), [readFully](../../../javax/imageio/stream/ImageInputStreamImpl.html#readFully%28short[],%20int,%20int%29), [readInt](../../../javax/imageio/stream/ImageInputStreamImpl.html#readInt%28%29), [readLine](../../../javax/imageio/stream/ImageInputStreamImpl.html#readLine%28%29), [readLong](../../../javax/imageio/stream/ImageInputStreamImpl.html#readLong%28%29), [readShort](../../../javax/imageio/stream/ImageInputStreamImpl.html#readShort%28%29), [readUnsignedByte](../../../javax/imageio/stream/ImageInputStreamImpl.html#readUnsignedByte%28%29), [readUnsignedInt](../../../javax/imageio/stream/ImageInputStreamImpl.html#readUnsignedInt%28%29), [readUnsignedShort](../../../javax/imageio/stream/ImageInputStreamImpl.html#readUnsignedShort%28%29), [readUTF](../../../javax/imageio/stream/ImageInputStreamImpl.html#readUTF%28%29), [reset](../../../javax/imageio/stream/ImageInputStreamImpl.html#reset%28%29), [seek](../../../javax/imageio/stream/ImageInputStreamImpl.html#seek%28long%29), [setBitOffset](../../../javax/imageio/stream/ImageInputStreamImpl.html#setBitOffset%28int%29), [setByteOrder](../../../javax/imageio/stream/ImageInputStreamImpl.html#setByteOrder%28java.nio.ByteOrder%29), [skipBytes](../../../javax/imageio/stream/ImageInputStreamImpl.html#skipBytes%28int%29), [skipBytes](../../../javax/imageio/stream/ImageInputStreamImpl.html#skipBytes%28long%29)`  
   * ### Methods inherited from class java.lang.[Object](../../../java/lang/Object.html "class in java.lang")  
   `[clone](../../../java/lang/Object.html#clone%28%29), [equals](../../../java/lang/Object.html#equals%28java.lang.Object%29), [getClass](../../../java/lang/Object.html#getClass%28%29), [hashCode](../../../java/lang/Object.html#hashCode%28%29), [notify](../../../java/lang/Object.html#notify%28%29), [notifyAll](../../../java/lang/Object.html#notifyAll%28%29), [toString](../../../java/lang/Object.html#toString%28%29), [wait](../../../java/lang/Object.html#wait%28%29), [wait](../../../java/lang/Object.html#wait%28long%29), [wait](../../../java/lang/Object.html#wait%28long,%20int%29)`

Constructor Detail

 * #### FileCacheImageInputStream  
 public FileCacheImageInputStream([InputStream](../../../java/io/InputStream.html "class in java.io") stream,  
                          [File](../../../java/io/File.html "class in java.io") cacheDir)  
                           throws [IOException](../../../java/io/IOException.html "class in java.io")  
 Constructs a `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).  
 Parameters:  
 `stream` \- an `InputStream` to read from.  
 `cacheDir` \- a `File` indicating where the cache file should be created, or `null` to use the system directory.  
 Throws:  
 `[IllegalArgumentException](../../../java/lang/IllegalArgumentException.html "class in java.lang")` \- if `stream` is`null`.  
 `[IllegalArgumentException](../../../java/lang/IllegalArgumentException.html "class in java.lang")` \- if `cacheDir` is non-`null` but is not a directory.  
 `[IOException](../../../java/io/IOException.html "class in java.io")` \- if a cache file cannot be created.

Method Detail

* #### read  
public int read()  
         throws [IOException](../../../java/io/IOException.html "class in java.io")  
Reads a single byte from the stream and returns it as an`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.  
**Specified by:**  
`[read](../../../javax/imageio/stream/ImageInputStream.html#read%28%29)` in interface `[ImageInputStream](../../../javax/imageio/stream/ImageInputStream.html "interface in javax.imageio.stream")`  
**Specified by:**  
`[read](../../../javax/imageio/stream/ImageInputStreamImpl.html#read%28%29)` in class `[ImageInputStreamImpl](../../../javax/imageio/stream/ImageInputStreamImpl.html "class in javax.imageio.stream")`  
Returns:  
the value of the next byte in the stream, or `-1` if EOF is reached.  
Throws:  
`[IOException](../../../java/io/IOException.html "class in java.io")` \- if the stream has been closed.  
* #### read  
public int read(byte[] b,  
       int off,  
       int len)  
         throws [IOException](../../../java/io/IOException.html "class in java.io")  
Reads up to `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.  
**Specified by:**  
`[read](../../../javax/imageio/stream/ImageInputStream.html#read%28byte[],%20int,%20int%29)` in interface `[ImageInputStream](../../../javax/imageio/stream/ImageInputStream.html "interface in javax.imageio.stream")`  
**Specified by:**  
`[read](../../../javax/imageio/stream/ImageInputStreamImpl.html#read%28byte[],%20int,%20int%29)` in class `[ImageInputStreamImpl](../../../javax/imageio/stream/ImageInputStreamImpl.html "class in javax.imageio.stream")`  
Parameters:  
`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.  
Returns:  
the number of bytes actually read, or `-1` to indicate EOF.  
Throws:  
`[IOException](../../../java/io/IOException.html "class in java.io")` \- if an I/O error occurs.  
* #### isCached  
public boolean isCached()  
Returns `true` since this`ImageInputStream` caches data in order to allow seeking backwards.  
**Specified by:**  
`[isCached](../../../javax/imageio/stream/ImageInputStream.html#isCached%28%29)` in interface `[ImageInputStream](../../../javax/imageio/stream/ImageInputStream.html "interface in javax.imageio.stream")`  
**Overrides:**  
`[isCached](../../../javax/imageio/stream/ImageInputStreamImpl.html#isCached%28%29)` in class `[ImageInputStreamImpl](../../../javax/imageio/stream/ImageInputStreamImpl.html "class in javax.imageio.stream")`  
Returns:  
`true`.  
See Also:  
[isCachedMemory()](../../../javax/imageio/stream/FileCacheImageInputStream.html#isCachedMemory%28%29), [isCachedFile()](../../../javax/imageio/stream/FileCacheImageInputStream.html#isCachedFile%28%29)  
* #### isCachedFile  
public boolean isCachedFile()  
Returns `true` since this`ImageInputStream` maintains a file cache.  
**Specified by:**  
`[isCachedFile](../../../javax/imageio/stream/ImageInputStream.html#isCachedFile%28%29)` in interface `[ImageInputStream](../../../javax/imageio/stream/ImageInputStream.html "interface in javax.imageio.stream")`  
**Overrides:**  
`[isCachedFile](../../../javax/imageio/stream/ImageInputStreamImpl.html#isCachedFile%28%29)` in class `[ImageInputStreamImpl](../../../javax/imageio/stream/ImageInputStreamImpl.html "class in javax.imageio.stream")`  
Returns:  
`true`.  
See Also:  
[isCached()](../../../javax/imageio/stream/FileCacheImageInputStream.html#isCached%28%29), [isCachedMemory()](../../../javax/imageio/stream/FileCacheImageInputStream.html#isCachedMemory%28%29)  
* #### isCachedMemory  
public boolean isCachedMemory()  
Returns `false` since this`ImageInputStream` does not maintain a main memory cache.  
**Specified by:**  
`[isCachedMemory](../../../javax/imageio/stream/ImageInputStream.html#isCachedMemory%28%29)` in interface `[ImageInputStream](../../../javax/imageio/stream/ImageInputStream.html "interface in javax.imageio.stream")`  
**Overrides:**  
`[isCachedMemory](../../../javax/imageio/stream/ImageInputStreamImpl.html#isCachedMemory%28%29)` in class `[ImageInputStreamImpl](../../../javax/imageio/stream/ImageInputStreamImpl.html "class in javax.imageio.stream")`  
Returns:  
`false`.  
See Also:  
[isCached()](../../../javax/imageio/stream/FileCacheImageInputStream.html#isCached%28%29), [isCachedFile()](../../../javax/imageio/stream/FileCacheImageInputStream.html#isCachedFile%28%29)  
* #### close  
public void close()  
           throws [IOException](../../../java/io/IOException.html "class in java.io")  
Closes this `FileCacheImageInputStream`, closing and removing the cache file. The source `InputStream` is not closed.  
**Specified by:**  
`[close](../../../java/io/Closeable.html#close%28%29)` in interface `[Closeable](../../../java/io/Closeable.html "interface in java.io")`  
**Specified by:**  
`[close](../../../java/lang/AutoCloseable.html#close%28%29)` in interface `[AutoCloseable](../../../java/lang/AutoCloseable.html "interface in java.lang")`  
**Specified by:**  
`[close](../../../javax/imageio/stream/ImageInputStream.html#close%28%29)` in interface `[ImageInputStream](../../../javax/imageio/stream/ImageInputStream.html "interface in javax.imageio.stream")`  
**Overrides:**  
`[close](../../../javax/imageio/stream/ImageInputStreamImpl.html#close%28%29)` in class `[ImageInputStreamImpl](../../../javax/imageio/stream/ImageInputStreamImpl.html "class in javax.imageio.stream")`  
Throws:  
`[IOException](../../../java/io/IOException.html "class in java.io")` \- if an error occurs.  
* #### finalize  
protected void finalize()  
                 throws [Throwable](../../../java/lang/Throwable.html "class in java.lang")  
Finalizes this object prior to garbage collection. The`close` method is called to close any open input source. This method should not be called from application code.  
**Overrides:**  
`[finalize](../../../javax/imageio/stream/ImageInputStreamImpl.html#finalize%28%29)` in class `[ImageInputStreamImpl](../../../javax/imageio/stream/ImageInputStreamImpl.html "class in javax.imageio.stream")`  
Throws:  
`[Throwable](../../../java/lang/Throwable.html "class in java.lang")` \- if an error occurs during superclass finalization.

Submit a bug or feature
For further API reference and developer documentation, see Java SE Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.
Copyright © 1993, 2020, Oracle and/or its affiliates. All rights reserved. Use is subject to license terms. Also see the documentation redistribution policy.

FileCacheImageInputStream (Java Platform SE 7 ) (original) (raw)

Field Summary

Constructor Summary

Method Summary

Constructor Detail

Method Detail