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org.apache.derby.impl.store.raw.data

public abstract Class BufferedByteHolderInputStream

extends ByteHolderInputStream
Class Inheritance
Known Direct Subclasses
org.apache.derby.impl.store.raw.data.DecryptInputStream, org.apache.derby.impl.store.raw.data.OverflowInputStream
Imports
java.io.IOException

Field Summary

Inherited from org.apache.derby.impl.store.raw.data.ByteHolderInputStream:
bh

Constructor Summary

AccessConstructor and Description
public

Method Summary

Modifier and TypeMethod and Description
public int
available()

Overrides org.apache.derby.impl.store.raw.data.ByteHolderInputStream.available.

Returns an estimate of the number of bytes that can be read (or skipped over) from this input stream without blocking, which may be 0, or 0 when end of stream is detected.

public abstract void
public int
read()

Overrides org.apache.derby.impl.store.raw.data.ByteHolderInputStream.read.

Reads the next byte of data from the input stream.

public int
read(byte[]
the buffer into which the data is read.
b
,
int
the start offset in array b at which the data is written.
off
,
int
the maximum number of bytes to read.
len
)

Overrides org.apache.derby.impl.store.raw.data.ByteHolderInputStream.read.

Reads up to len bytes of data from the input stream into an array of bytes.

public long
skip(long
the number of bytes to be skipped.
count
)

Overrides org.apache.derby.impl.store.raw.data.ByteHolderInputStream.skip.

Skips over and discards n bytes of data from this input stream.

Inherited from org.apache.derby.impl.store.raw.data.ByteHolderInputStream:
getByteHoldersetByteHolder

Constructor Detail

BufferedByteHolderInputStreamback to summary
public BufferedByteHolderInputStream(ByteHolder bh)

Method Detail

availableback to summary
public int available() throws IOException

Overrides org.apache.derby.impl.store.raw.data.ByteHolderInputStream.available.

Doc from java.io.InputStream.available.

Returns an estimate of the number of bytes that can be read (or skipped over) from this input stream without blocking, which may be 0, or 0 when end of stream is detected. The read might be on the same thread or another thread. A single read or skip of this many bytes will not block, but may read or skip fewer bytes.

Note that while some implementations of InputStream will return the total number of bytes in the stream, many will not. It is never correct to use the return value of this method to allocate a buffer intended to hold all data in this stream.

A subclass's implementation of this method may choose to throw an IOException if this input stream has been closed by invoking the close() method.

Returns:int

an estimate of the number of bytes that can be read (or skipped over) from this input stream without blocking or 0 when it reaches the end of the input stream.

Exceptions
IOException:
if an I/O error occurs.
fillByteHolderback to summary
public abstract void fillByteHolder() throws IOException
readback to summary
public int read() throws IOException

Overrides org.apache.derby.impl.store.raw.data.ByteHolderInputStream.read.

Doc from java.io.InputStream.read.

Reads the next byte of data from the input stream. The value byte is returned as an int in the range 0 to 255. If no byte is available because the end of the stream has been reached, the value -1 is returned. This method blocks until input data is available, the end of the stream is detected, or an exception is thrown.

Returns:int

the next byte of data, or -1 if the end of the stream is reached.

Exceptions
IOException:
if an I/O error occurs.
readback to summary
public int read(byte[] b, int off, int len) throws IOException

Overrides org.apache.derby.impl.store.raw.data.ByteHolderInputStream.read.

Doc from java.io.InputStream.read.

Reads up to len bytes of data from the input stream into an array of bytes. An attempt is made to read as many as len bytes, but a smaller number may be read. The number of bytes actually read is returned as an integer.

This method blocks until input data is available, end of file is detected, or an exception is thrown.

If len is zero, then no bytes are read and 0 is returned; otherwise, there is an attempt to read at least one byte. If no byte is available because the stream is at end of file, the value -1 is returned; otherwise, at least one byte is read and stored into b.

The first byte read is stored into element b[off], the next one into b[off+1], and so on. The number of bytes read is, at most, equal to len. Let k be the number of bytes actually read; these bytes will be stored in elements b[off] through b[off+k-1], leaving elements b[off+k] through b[off+len-1] unaffected.

In every case, elements b[0] through b[off-1] and elements b[off+len] through b[b.length-1] are unaffected.

Parameters
b:byte[]

the buffer into which the data is read.

off:int

the start offset in array b at which the data is written.

len:int

the maximum number of bytes to read.

Returns:int

the total number of bytes read into the buffer, or -1 if there is no more data because the end of the stream has been reached.

Exceptions
IOException:
If the first byte cannot be read for any reason other than end of file, or if the input stream has been closed, or if some other I/O error occurs.
skipback to summary
public long skip(long count) throws IOException

Overrides org.apache.derby.impl.store.raw.data.ByteHolderInputStream.skip.

Doc from java.io.InputStream.skip.

Skips over and discards n bytes of data from this input stream. The skip method may, for a variety of reasons, end up skipping over some smaller number of bytes, possibly 0. This may result from any of a number of conditions; reaching end of file before n bytes have been skipped is only one possibility. The actual number of bytes skipped is returned. If n is negative, the skip method for class InputStream always returns 0, and no bytes are skipped. Subclasses may handle the negative value differently.

Parameters
count:long

the number of bytes to be skipped.

Returns:long

the actual number of bytes skipped which might be zero.

Exceptions
IOException:
if an I/O error occurs.