eve.database.implement

Class DatabaseObject.MetaData

java.lang.Object

java.io.InputStream

eve.io.RandomStream

eve.database.implement.DatabaseObject.MetaData

Enclosing class:

DatabaseObject

protected abstract class DatabaseObject.MetaData
extends RandomStream

Field Summary

Fields

Modifier and Type	Field and Description
int	numberOfFragments This is only valid after a read operation.

Fields inherited from class eve.io.RandomStream

READ_ONLY, READ_WRITE

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	MetaData(String name)

Method Summary

Modifier and Type	Method and Description
abstract void	close() This method closes the stream.
abstract boolean	delete()
abstract long	getLength() Return the full length of the Stream.
byte[]	openAndReadAll()
ByteArray	openAndReadAll(ByteArray ba)
abstract boolean	openForAppending(boolean mustExist)
abstract void	openForOverwriting(int bytesNeededToWrite)
abstract int	openForReading()
abstract void	openForReplacing(int bytesNeededToWrite)
int	read() This method reads an unsigned byte from the input stream and returns it as an int in the range of 0-255.
abstract int	read(byte[] data, int offset, int length) This method read bytes from a stream and stores them into a caller supplied buffer.
void	readAll(byte[] data, int offset, int length)
abstract void	write(byte[] data, int offset, int length) This method writes len bytes from the specified array b starting at index off into the array.
void	write(int b) This method writes a single byte to the output stream.

Methods inherited from class eve.io.RandomStream

canSetLength, flush, getPosition, isOpenForWriting, isReadWrite, mark, markSupported, reset, setLength, setMode, setPosition, skip, throwCantWrite, toOutputStream, validateMode, write

Methods inherited from class java.io.InputStream

available, finalize, hashCode, read

Methods inherited from class java.lang.Object

clone, equals, getClass, notify, notifyAll, toString, wait, wait, wait

Field Detail

numberOfFragments

public int numberOfFragments

This is only valid after a read operation.

Constructor Detail

MetaData

protected MetaData(String name)

Method Detail

openForReplacing

public abstract void openForReplacing(int bytesNeededToWrite)
                               throws IOException

Throws:

IOException

openForAppending

public abstract boolean openForAppending(boolean mustExist)
                                  throws IOException

Throws:

IOException

openForOverwriting

public abstract void openForOverwriting(int bytesNeededToWrite)
                                 throws IOException

Throws:

IOException

openForReading

public abstract int openForReading()
                            throws IOException

Throws:

IOException

write

public abstract void write(byte[] data,
                           int offset,
                           int length)
                    throws IOException

Description copied from class: RandomStream

This method writes len bytes from the specified array b starting at index off into the array.

This method in this class calls the single byte write() method in a loop until all bytes have been written. Subclasses should override this method if possible in order to provide a more efficent implementation.

Overrides:

write in class RandomStream

Parameters:

data - The array of bytes to write from

offset - The index into the array to start writing from

length - The number of bytes to write

Throws:

IOException - If an error occurs

write

public void write(int b)
           throws IOException

Description copied from class: RandomStream

This method writes a single byte to the output stream. The byte written is the low eight bits of the int passed as the argument.

Subclasses must provide an implementation of this method.

Overrides:

write in class RandomStream

Parameters:

b - The byte to be written to the output stream, passed as the low eight bits of an int

Throws:

IOException - If an error occurs

read

public abstract int read(byte[] data,
                         int offset,
                         int length)
                  throws IOException

Description copied from class: InputStream

This method read bytes from a stream and stores them into a caller supplied buffer. It starts storing the data at index off into the buffer and attempts to read len bytes. This method can return before reading the number of bytes requested. The actual number of bytes read is returned as an int. A -1 is returned to indicate the end of the stream.

This method will block until some data can be read.

This method operates by calling the single byte read() method in a loop until the desired number of bytes are read. The read loop stops short if the end of the stream is encountered or if an IOException is encountered on any read operation except the first. If the first attempt to read a bytes fails, the IOException is allowed to propagate upward. And subsequent IOException is caught and treated identically to an end of stream condition. Subclasses can (and should if possible) override this method to provide a more efficient implementation.

Overrides:

read in class InputStream

Parameters:

data - The array into which the bytes read should be stored

offset - The offset into the array to start storing bytes

length - The requested number of bytes to read

Returns:

The actual number of bytes read, or -1 if end of stream.

Throws:

IOException - If an error occurs.

read

public int read()
         throws IOException

Description copied from class: InputStream

This method reads an unsigned byte from the input stream and returns it as an int in the range of 0-255. This method also will return -1 if the end of the stream has been reached.

This method will block until the byte can be read.

Overrides:

read in class InputStream

Returns:

The byte read or -1 if end of stream

Throws:

IOException - If an error occurs

getLength

public abstract long getLength()
                        throws IOException

Description copied from class: RandomStream

Return the full length of the Stream.

Overrides:

getLength in class RandomStream

Throws:

IOException - if an IO error occured.

delete

public abstract boolean delete()
                        throws IOException

Throws:

IOException

close

public abstract void close()
                    throws IOException

Description copied from class: InputStream

This method closes the stream. Any futher attempts to read from the stream may generate an IOException

This method does nothing in this class, but subclasses may override this method in order to provide additional functionality.

Overrides:

close in class InputStream

Throws:

IOException - If an error occurs, which can only happen in a subclass

readAll

public void readAll(byte[] data,
                    int offset,
                    int length)
             throws IOException

Throws:

IOException

openAndReadAll

public ByteArray openAndReadAll(ByteArray ba)
                         throws IOException

Throws:

IOException

openAndReadAll

public byte[] openAndReadAll()
                      throws IOException

Throws:

IOException