public class

MemoryCacheImageInputStream

extends ImageInputStreamImpl

java.lang.Object
↳	javax.imageio.stream.ImageInputStreamImpl
	↳	javax.imageio.stream.MemoryCacheImageInputStream

Class Overview

An implementation of ImageInputStream that gets its input from a regular InputStream. A memory buffer is used to cache at least the data between the discard position and the current read position.

In general, it is preferable to use a FileCacheImageInputStream when reading from a regular InputStream. This class is provided for cases where it is not possible to create a writable temporary file.

Summary

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Inherited Fields

From class javax.imageio.stream.ImageInputStreamImpl

Public Constructors
	MemoryCacheImageInputStream(InputStream stream) Constructs a `MemoryCacheImageInputStream` that will read from a given `InputStream`.

Public Methods
void	close() Closes this `MemoryCacheImageInputStream`, freeing the cache.
void	flushBefore(long pos) Discards the initial portion of the stream prior to the indicated postion.
boolean	isCached() Returns `true` since this `ImageInputStream` caches data in order to allow seeking backwards.
boolean	isCachedFile() Returns `false` since this `ImageInputStream` does not maintain a file cache.
boolean	isCachedMemory() Returns `true` since this `ImageInputStream` maintains 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`.

Protected Methods
void	finalize() Finalizes this object prior to garbage collection.

[Expand]

Inherited Methods

From class javax.imageio.stream.ImageInputStreamImpl

final void	checkClosed() Throws an `IOException` if the stream has been closed.
void	close() Closes the stream.
void	finalize() Finalizes this object prior to garbage collection.
void	flush() Discards the initial position of the stream prior to the current stream position.
void	flushBefore(long pos) Discards the initial portion of the stream prior to the indicated postion.
int	getBitOffset() Returns the current bit offset, as an integer between 0 and 7, inclusive.
ByteOrder	getByteOrder() Returns the byte order with which data values will be read from this stream as an instance of the `java.nio.ByteOrder` enumeration.
long	getFlushedPosition() Returns the earliest position in the stream to which seeking may be performed.
long	getStreamPosition() Returns the current byte position of the stream.
boolean	isCached() Default implementation returns false.
boolean	isCachedFile() Default implementation returns false.
boolean	isCachedMemory() Default implementation returns false.
long	length() Returns `-1L` to indicate that the stream has unknown length.
void	mark() Pushes the current stream position onto a stack of marked positions.
abstract 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`.
int	read(byte[] b) A convenience method that calls `read(b, 0, b.length)`.
abstract int	read() Reads a single byte from the stream and returns it as an `int` between 0 and 255.
int	readBit() Reads a single bit from the stream and returns it as an `int` with the value `0` or `1`.
long	readBits(int numBits) Reads a bitstring from the stream and returns it as a `long`, with the first bit read becoming the most significant bit of the output.
boolean	readBoolean() Reads a byte from the stream and returns a `boolean` value of `true` if it is nonzero, `false` if it is zero.
byte	readByte() Reads a byte from the stream and returns it as a `byte` value.
void	readBytes(IIOByteBuffer buf, int len) Reads up to `len` bytes from the stream, and modifies the supplied `IIOByteBuffer` to indicate the byte array, offset, and length where the data may be found.
char	readChar() Equivalent to `readUnsignedShort`, except that the result is returned using the `char` datatype.
double	readDouble() Reads 8 bytes from the stream, and (conceptually) concatenates them according to the current byte order and returns the result as a `double`.
float	readFloat() Reads 4 bytes from the stream, and (conceptually) concatenates them according to the current byte order and returns the result as a `float`.
void	readFully(byte[] b) Reads `b.length` bytes from the stream, and stores them into `b` starting at index `0`.
void	readFully(byte[] b, int off, int len) Reads `len` bytes from the stream, and stores them into `b` starting at index `off`.
void	readFully(char[] c, int off, int len) Reads `len` chars (unsigned 16-bit integers) from the stream according to the current byte order, and stores them into `c` starting at index `off`.
void	readFully(int[] i, int off, int len) Reads `len` ints (signed 32-bit integers) from the stream according to the current byte order, and stores them into `i` starting at index `off`.
void	readFully(float[] f, int off, int len) Reads `len` floats (32-bit IEEE single-precision floats) from the stream according to the current byte order, and stores them into `f` starting at index `off`.
void	readFully(short[] s, int off, int len) Reads `len` shorts (signed 16-bit integers) from the stream according to the current byte order, and stores them into `s` starting at index `off`.
void	readFully(double[] d, int off, int len) Reads `len` doubles (64-bit IEEE double-precision floats) from the stream according to the current byte order, and stores them into `d` starting at index `off`.
void	readFully(long[] l, int off, int len) Reads `len` longs (signed 64-bit integers) from the stream according to the current byte order, and stores them into `l` starting at index `off`.
int	readInt() Reads 4 bytes from the stream, and (conceptually) concatenates them according to the current byte order and returns the result as an `int`.
String	readLine() Reads the next line of text from the input stream.
long	readLong() Reads 8 bytes from the stream, and (conceptually) concatenates them according to the current byte order and returns the result as a `long`.
short	readShort() Reads two bytes from the stream, and (conceptually) concatenates them according to the current byte order, and returns the result as a `short` value.
String	readUTF() Reads in a string that has been encoded using a modified UTF-8 format.
int	readUnsignedByte() Reads a byte from the stream, and (conceptually) converts it to an int, masks it with `0xff` in order to strip off any sign-extension bits, and returns it as a `byte` value.
long	readUnsignedInt() Reads 4 bytes from the stream, and (conceptually) concatenates them according to the current byte order, converts the result to a long, masks it with `0xffffffffL` in order to strip off any sign-extension bits, and returns the result as an unsigned `long` value.
int	readUnsignedShort() Reads two bytes from the stream, and (conceptually) concatenates them according to the current byte order, converts the resulting value to an `int`, masks it with `0xffff` in order to strip off any sign-extension buts, and returns the result as an unsigned `int` value.
void	reset() Resets the current stream byte and bit positions from the stack of marked positions.
void	seek(long pos) Sets the current stream position to the desired location.
void	setBitOffset(int bitOffset) Sets the bit offset to an integer between 0 and 7, inclusive.
void	setByteOrder(ByteOrder byteOrder) Sets the desired byte order for future reads of data values from this stream.
long	skipBytes(long n) Advances the current stream position by calling `seek(getStreamPosition() + n)`.
int	skipBytes(int n) Advances the current stream position by calling `seek(getStreamPosition() + n)`.

From class java.lang.Object

Object	clone() Creates and returns a copy of this object.
boolean	equals(Object obj) Indicates whether some other object is "equal to" this one.
void	finalize() Called by the garbage collector on an object when garbage collection determines that there are no more references to the object.
final Class<?>	getClass() Returns the runtime class of this `Object`.
int	hashCode() Returns a hash code value for the object.
final void	notify() Wakes up a single thread that is waiting on this object's monitor.
final void	notifyAll() Wakes up all threads that are waiting on this object's monitor.
String	toString() Returns a string representation of the object.
final void	wait() Causes the current thread to wait until another thread invokes the `notify()` method or the `notifyAll()` method for this object.
final void	wait(long timeout, int nanos) Causes the current thread to wait until another thread invokes the `notify()` method or the `notifyAll()` method for this object, or some other thread interrupts the current thread, or a certain amount of real time has elapsed.
final void	wait(long timeout) Causes the current thread to wait until either another thread invokes the `notify()` method or the `notifyAll()` method for this object, or a specified amount of time has elapsed.

From interface java.io.DataInput

abstract boolean	readBoolean() Reads one input byte and returns `true` if that byte is nonzero, `false` if that byte is zero.
abstract byte	readByte() Reads and returns one input byte.
abstract char	readChar() Reads two input bytes and returns a `char` value.
abstract double	readDouble() Reads eight input bytes and returns a `double` value.
abstract float	readFloat() Reads four input bytes and returns a `float` value.
abstract void	readFully(byte[] b) Reads some bytes from an input stream and stores them into the buffer array `b`.
abstract void	readFully(byte[] b, int off, int len) Reads `len` bytes from an input stream.
abstract int	readInt() Reads four input bytes and returns an `int` value.
abstract String	readLine() Reads the next line of text from the input stream.
abstract long	readLong() Reads eight input bytes and returns a `long` value.
abstract short	readShort() Reads two input bytes and returns a `short` value.
abstract String	readUTF() Reads in a string that has been encoded using a modified UTF-8 format.
abstract int	readUnsignedByte() Reads one input byte, zero-extends it to type `int`, and returns the result, which is therefore in the range `0` through `255`.
abstract int	readUnsignedShort() Reads two input bytes and returns an `int` value in the range `0` through `65535`.
abstract int	skipBytes(int n) Makes an attempt to skip over `n` bytes of data from the input stream, discarding the skipped bytes.

From interface javax.imageio.stream.ImageInputStream

abstract void	close() Closes the stream.
abstract void	flush() Discards the initial position of the stream prior to the current stream position.
abstract void	flushBefore(long pos) Discards the initial portion of the stream prior to the indicated postion.
abstract int	getBitOffset() Returns the current bit offset, as an integer between 0 and 7, inclusive.
abstract ByteOrder	getByteOrder() Returns the byte order with which data values will be read from this stream as an instance of the `java.nio.ByteOrder` enumeration.
abstract long	getFlushedPosition() Returns the earliest position in the stream to which seeking may be performed.
abstract long	getStreamPosition() Returns the current byte position of the stream.
abstract boolean	isCached() Returns `true` if this `ImageInputStream` caches data itself in order to allow seeking backwards.
abstract boolean	isCachedFile() Returns `true` if this `ImageInputStream` caches data itself in order to allow seeking backwards, and the cache is kept in a temporary file.
abstract boolean	isCachedMemory() Returns `true` if this `ImageInputStream` caches data itself in order to allow seeking backwards, and the cache is kept in main memory.
abstract long	length() Returns the total length of the stream, if known.
abstract void	mark() Marks a position in the stream to be returned to by a subsequent call to `reset`.
abstract 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`.
abstract int	read(byte[] b) Reads up to `b.length` bytes from the stream, and stores them into `b` starting at index 0.
abstract int	read() Reads a single byte from the stream and returns it as an integer between 0 and 255.
abstract int	readBit() Reads a single bit from the stream and returns it as an `int` with the value `0` or `1`.
abstract long	readBits(int numBits) Reads a bitstring from the stream and returns it as a `long`, with the first bit read becoming the most significant bit of the output.
abstract boolean	readBoolean() Reads a byte from the stream and returns a `boolean` value of `true` if it is nonzero, `false` if it is zero.
abstract byte	readByte() Reads a byte from the stream and returns it as a `byte` value.
abstract void	readBytes(IIOByteBuffer buf, int len) Reads up to `len` bytes from the stream, and modifies the supplied `IIOByteBuffer` to indicate the byte array, offset, and length where the data may be found.
abstract char	readChar() Equivalent to `readUnsignedShort`, except that the result is returned using the `char` datatype.
abstract double	readDouble() Reads 8 bytes from the stream, and (conceptually) concatenates them according to the current byte order and returns the result as a `double`.
abstract float	readFloat() Reads 4 bytes from the stream, and (conceptually) concatenates them according to the current byte order and returns the result as a `float`.
abstract void	readFully(byte[] b) Reads `b.length` bytes from the stream, and stores them into `b` starting at index `0`.
abstract void	readFully(byte[] b, int off, int len) Reads `len` bytes from the stream, and stores them into `b` starting at index `off`.
abstract void	readFully(char[] c, int off, int len) Reads `len` chars (unsigned 16-bit integers) from the stream according to the current byte order, and stores them into `c` starting at index `off`.
abstract void	readFully(int[] i, int off, int len) Reads `len` ints (signed 32-bit integers) from the stream according to the current byte order, and stores them into `i` starting at index `off`.
abstract void	readFully(float[] f, int off, int len) Reads `len` floats (32-bit IEEE single-precision floats) from the stream according to the current byte order, and stores them into `f` starting at index `off`.
abstract void	readFully(short[] s, int off, int len) Reads `len` shorts (signed 16-bit integers) from the stream according to the current byte order, and stores them into `s` starting at index `off`.
abstract void	readFully(double[] d, int off, int len) Reads `len` doubles (64-bit IEEE double-precision floats) from the stream according to the current byte order, and stores them into `d` starting at index `off`.
abstract void	readFully(long[] l, int off, int len) Reads `len` longs (signed 64-bit integers) from the stream according to the current byte order, and stores them into `l` starting at index `off`.
abstract int	readInt() Reads 4 bytes from the stream, and (conceptually) concatenates them according to the current byte order and returns the result as an `int`.
abstract String	readLine() Reads the next line of text from the input stream.
abstract long	readLong() Reads 8 bytes from the stream, and (conceptually) concatenates them according to the current byte order and returns the result as a `long`.
abstract short	readShort() Reads two bytes from the stream, and (conceptually) concatenates them according to the current byte order, and returns the result as a `short` value.
abstract String	readUTF() Reads in a string that has been encoded using a modified UTF-8 format.
abstract int	readUnsignedByte() Reads a byte from the stream, and (conceptually) converts it to an int, masks it with `0xff` in order to strip off any sign-extension bits, and returns it as a `byte` value.
abstract long	readUnsignedInt() Reads 4 bytes from the stream, and (conceptually) concatenates them according to the current byte order, converts the result to a long, masks it with `0xffffffffL` in order to strip off any sign-extension bits, and returns the result as an unsigned `long` value.
abstract int	readUnsignedShort() Reads two bytes from the stream, and (conceptually) concatenates them according to the current byte order, converts the resulting value to an `int`, masks it with `0xffff` in order to strip off any sign-extension buts, and returns the result as an unsigned `int` value.
abstract void	reset() Returns the stream pointer to its previous position, including the bit offset, at the time of the most recent unmatched call to `mark`.
abstract void	seek(long pos) Sets the current stream position to the desired location.
abstract void	setBitOffset(int bitOffset) Sets the bit offset to an integer between 0 and 7, inclusive.
abstract void	setByteOrder(ByteOrder byteOrder) Sets the desired byte order for future reads of data values from this stream.
abstract long	skipBytes(long n) Moves the stream position forward by a given number of bytes.
abstract int	skipBytes(int n) Moves the stream position forward by a given number of bytes.

Public Constructors

public MemoryCacheImageInputStream (InputStream stream)

Constructs a MemoryCacheImageInputStream that will read from a given InputStream.

Parameters

stream	an `InputStream` to read from.

Throws

IllegalArgumentException	if `stream` is `null`.

Public Methods

public void close ()

Closes this MemoryCacheImageInputStream, freeing the cache. The source InputStream is not closed.

Throws

IOException

public void flushBefore (long pos)

Discards the initial portion of the stream prior to the indicated postion. Attempting to seek to an offset within the flushed portion of the stream will result in an IndexOutOfBoundsException.

Calling flushBefore may allow classes implementing this interface to free up resources such as memory or disk space that are being used to store data from the stream.

Parameters

pos	a `long` containing the length of the stream prefix that may be flushed.

Throws

IOException

public boolean isCached ()

Returns true since this ImageInputStream caches data in order to allow seeking backwards.

Returns

true.

public boolean isCachedFile ()

Returns false since this ImageInputStream does not maintain a file cache.

Returns

false.

public boolean isCachedMemory ()

Returns true since this ImageInputStream maintains a main memory cache.

Returns

true.

public int read ()

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.

Returns

the value of the next byte in the stream, or -1 if EOF is reached.

Throws

IOException

public 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. 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.

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

Protected Methods

protected void finalize ()

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.

Throws

Throwable

Interfaces

Classes

MemoryCacheImageInputStream

Class Overview

Summary

Public Constructors

public MemoryCacheImageInputStream (InputStream stream)

Parameters

Throws

Public Methods

public void close ()

Throws

public void flushBefore (long pos)

Parameters

Throws

public boolean isCached ()

Returns

See Also

public boolean isCachedFile ()

Returns

See Also

public boolean isCachedMemory ()

Returns

See Also

public int read ()

Returns

Throws

public int read (byte[] b, int off, int len)

Parameters

Returns

Throws

Protected Methods

protected void finalize ()

Throws