Class MemByteHolder
- java.lang.Object
-
- org.apache.derby.impl.store.raw.data.MemByteHolder
-
- All Implemented Interfaces:
ByteHolder
public class MemByteHolder extends java.lang.Object implements ByteHolder
A ByteHolder that stores all its bytes in memory.
-
-
Field Summary
Fields Modifier and Type Field Description (package private) int
bufSize
(package private) java.util.Vector<byte[]>
bufV
(package private) byte[]
curBuf
(package private) int
curBufDataBytes
(package private) int
curBufPos
(package private) int
curBufVEleAt
(package private) int
lastBufDataBytes
(package private) int
lastBufVEleAt
(package private) boolean
writing
-
Constructor Summary
Constructors Constructor Description MemByteHolder(int bufSize)
Create a new MemByteHolder.
-
Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description int
available()
Return the number of bytes that can be read from this ByteHolder without blocking on an IO.void
clear()
Clear the bytes from the ByteHolder and place it in writing mode.ByteHolder
cloneEmpty()
Return a byte holder matching existing type and size of current ByteHolder, but don't bother to fill the bytes.private java.lang.String
dumpBuf(int bufVEleAt)
Create a string representation of an internal buffer of bytes.protected boolean
getNextBuffer_r()
Get the next buffer for reading bytes.protected void
getNextBuffer_w()
Get the next buffer for writing bytes.protected void
getNextBuffer_w_Sanity()
Do sanity checking when getting the next write bufferprotected void
initBuffer_w()
Initialize a buffer for writingint
numBytesSaved()
Return the number of bytes that have been saved to this byte holder.int
read()
Read a byte from this ByteHolder.int
read(byte[] b, int off, int len)
Read up to 'len' bytes from this ByteHolder and store them in an array at offset 'off'.int
read(byte[] b, int off, java.io.OutputStream out, int len)
int
read(java.io.OutputStream out, int len)
Read from the ByteHolder.int
shiftToFront()
shift the remaining unread bytes to the beginning of the byte holderlong
skip(long count)
Skip over the specified number of bytes in a ByteHolder.void
startReading()
Place a ByteHolder in reading mode.java.lang.String
toString()
Produce a string describing the state of this ByteHolder.void
write(byte[] data, int offset, int len)
Write len bytes of data starting at 'offset' to this ByteHolder.void
write(int b)
Write a byte to this ByteHolder.long
write(java.io.InputStream is, long count)
Write up to count bytes from an input stream to this ByteHolder.boolean
writingMode()
Return true if this is in writing mode.
-
-
-
Method Detail
-
write
public void write(int b) throws java.io.IOException
Description copied from interface:ByteHolder
Write a byte to this ByteHolder.The ByteHolder must be in writing mode to call this.
- Specified by:
write
in interfaceByteHolder
- Throws:
java.io.IOException
- Thrown on error- See Also:
ByteHolder.write(int)
-
write
public void write(byte[] data, int offset, int len) throws java.io.IOException
Description copied from interface:ByteHolder
Write len bytes of data starting at 'offset' to this ByteHolder.The ByteHolder must be in writing mode to call this.
- Specified by:
write
in interfaceByteHolder
- Throws:
java.io.IOException
- Thrown on error- See Also:
ByteHolder.write(int)
-
write
public long write(java.io.InputStream is, long count) throws java.io.IOException
Description copied from interface:ByteHolder
Write up to count bytes from an input stream to this ByteHolder. This may write fewer bytes if it encounters an end of file on the input stream.- Specified by:
write
in interfaceByteHolder
- Returns:
- the number of bytes written.
- Throws:
java.io.IOException
- Thrown on error- See Also:
ByteHolder.write(int)
-
clear
public void clear() throws java.io.IOException
Description copied from interface:ByteHolder
Clear the bytes from the ByteHolder and place it in writing mode. This may not free the memory the ByteHolder uses to store data.- Specified by:
clear
in interfaceByteHolder
- Throws:
java.io.IOException
- Thrown on error- See Also:
ByteHolder.clear()
-
startReading
public void startReading() throws java.io.IOException
Description copied from interface:ByteHolder
Place a ByteHolder in reading mode. After this call, reads scan bytes sequentially in the order they were written to the ByteHolder starting from the first byte. When the ByteHolder is already in readmode this simply arranges for reads to start at the beginning of the sequence of saved bytes.- Specified by:
startReading
in interfaceByteHolder
- Throws:
java.io.IOException
- See Also:
ByteHolder.startReading()
-
read
public int read() throws java.io.IOException
Description copied from interface:ByteHolder
Read a byte from this ByteHolder.The ByteHolder must be in reading mode to call this.
- Specified by:
read
in interfaceByteHolder
- Returns:
- The byte or -1 if there are no bytes available.
- Throws:
java.io.IOException
- Thrown on error- See Also:
ByteHolder.read()
-
read
public int read(byte[] b, int off, int len) throws java.io.IOException
Description copied from interface:ByteHolder
Read up to 'len' bytes from this ByteHolder and store them in an array at offset 'off'.The ByteHolder must be in reading mode to call this.
- Specified by:
read
in interfaceByteHolder
- Returns:
- the number of bytes read or -1 if the this ByteHolder has no more bytes.
- Throws:
java.io.IOException
- Thrown on error- See Also:
ByteHolder.read()
-
read
public int read(java.io.OutputStream out, int len) throws java.io.IOException
Description copied from interface:ByteHolder
Read from the ByteHolder.Read up to 'len' bytes from this ByteHolder and write them to the OutputStream
The ByteHolder must be in reading mode to call this.
- Specified by:
read
in interfaceByteHolder
- Returns:
- the number of bytes read or -1 if the this ByteHolder has no more bytes.
- Throws:
java.io.IOException
- Thrown on error- See Also:
ByteHolder.read()
-
read
public int read(byte[] b, int off, java.io.OutputStream out, int len) throws java.io.IOException
- Throws:
java.io.IOException
- Thrown on error- See Also:
ByteHolder.read()
-
shiftToFront
public int shiftToFront() throws java.io.IOException
Description copied from interface:ByteHolder
shift the remaining unread bytes to the beginning of the byte holder- Specified by:
shiftToFront
in interfaceByteHolder
- Throws:
java.io.IOException
- Thrown on error- See Also:
ByteHolder.shiftToFront()
-
available
public int available()
Description copied from interface:ByteHolder
Return the number of bytes that can be read from this ByteHolder without blocking on an IO.- Specified by:
available
in interfaceByteHolder
- See Also:
ByteHolder.available()
-
numBytesSaved
public int numBytesSaved()
Return the number of bytes that have been saved to this byte holder. This result is different from available() as it is unaffected by the current read position on the ByteHolder.- Specified by:
numBytesSaved
in interfaceByteHolder
- See Also:
ByteHolder.numBytesSaved()
-
skip
public long skip(long count) throws java.io.IOException
Description copied from interface:ByteHolder
Skip over the specified number of bytes in a ByteHolder.- Specified by:
skip
in interfaceByteHolder
- Throws:
java.io.IOException
- Thrown on error- See Also:
ByteHolder.skip(long)
-
writingMode
public boolean writingMode()
Description copied from interface:ByteHolder
Return true if this is in writing mode.- Specified by:
writingMode
in interfaceByteHolder
- See Also:
ByteHolder.writingMode()
-
cloneEmpty
public ByteHolder cloneEmpty()
Description copied from interface:ByteHolder
Return a byte holder matching existing type and size of current ByteHolder, but don't bother to fill the bytes. Normal usage is expected to reset the holding stream to the beginning, so the copy of current state would be wasted.- Specified by:
cloneEmpty
in interfaceByteHolder
- Returns:
- An empty
ByteHolder
. - See Also:
ByteHolder.cloneEmpty()
-
getNextBuffer_w
protected void getNextBuffer_w() throws java.io.IOException
Get the next buffer for writing bytes.- Throws:
java.io.IOException
- Thrown on error
-
getNextBuffer_w_Sanity
protected void getNextBuffer_w_Sanity()
Do sanity checking when getting the next write buffer
-
initBuffer_w
protected void initBuffer_w()
Initialize a buffer for writing
-
getNextBuffer_r
protected boolean getNextBuffer_r() throws java.io.IOException
Get the next buffer for reading bytes.- Returns:
- true if the user has read all the bytes in this ByteHolder.
- Throws:
java.io.IOException
- Thrown on error
-
dumpBuf
private java.lang.String dumpBuf(int bufVEleAt)
Create a string representation of an internal buffer of bytes. This is useful during debugging.
-
toString
public java.lang.String toString()
Produce a string describing the state of this ByteHolder. This is mainly for debugging.- Overrides:
toString
in classjava.lang.Object
-
-