ucar.unidata.io.http

Class HTTPRandomAccessFile

java.lang.Object

ucar.unidata.io.RandomAccessFile

ucar.unidata.io.http.HTTPRandomAccessFile

All Implemented Interfaces:

DataInput, DataOutput, FileCacheable

public class HTTPRandomAccessFile
extends RandomAccessFile

Gives access to files over HTTP, using "Accept-Ranges" HTTP header to do random access. This version uses a single instance of HttpClient, following performance guidelines at http://jakarta.apache.org/commons/httpclient/performance.html Plus other improvements.

Author:

John Caron, based on work by Donald Denbo

Field Summary

Fields

Modifier and Type	Field and Description
static int	defaultHTTPBufferSize

Fields inherited from class ucar.unidata.io.RandomAccessFile

allFiles, BIG_ENDIAN, bigEndian, buffer, bufferStart, dataEnd, dataSize, debugAccess, debugLeaks, defaultBufferSize, endOfFile, file, fileCache, fileChannel, filePosition, LITTLE_ENDIAN, location, openFiles, readonly, showOpen, showRead

Constructor Summary

Constructors

Constructor and Description
HTTPRandomAccessFile(String url)
HTTPRandomAccessFile(String url, int bufferSize)

Method Summary

Methods

Modifier and Type	Method and Description
void	close() Close the file, and release any associated system resources.
long	length() Get the length of the file.
protected int	read_(long pos, byte[] buff, int offset, int len) Read directly from file, without going through the buffer.
long	readToByteChannel(WritableByteChannel dest, long offset, long nbytes) Read nbytes bytes, at the specified file offset, send to a WritableByteChannel.

Methods inherited from class ucar.unidata.io.RandomAccessFile

flush, getAllFiles, getBufferSize, getDebugLeaks, getDebugNbytes, getDebugNseeks, getFilePointer, getLastModified, getLocation, getOpenFiles, getRandomAccessFile, isAtEndOfFile, order, order, read, read, read, readBoolean, readBuffer, readByte, readBytes, readBytes, readChar, readDouble, readDouble, readFloat, readFloat, readFully, readFully, readInt, readInt, readIntUnbuffered, readLine, readLong, readLong, readShort, readShort, readString, readUnsignedByte, readUnsignedShort, readUTF, searchForward, seek, setBufferSize, setDebugAccess, setDebugLeaks, setExtendMode, setFileCache, setMinLength, skipBytes, skipBytes, toString, unread, write, write, write, writeBoolean, writeBoolean, writeByte, writeBytes, writeBytes, writeBytes, writeChar, writeChar, writeChars, writeDouble, writeDouble, writeFloat, writeFloat, writeInt, writeInt, writeLong, writeLong, writeShort, writeShort, writeUTF

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

defaultHTTPBufferSize

public static int defaultHTTPBufferSize

Constructor Detail

HTTPRandomAccessFile

public HTTPRandomAccessFile(String url)
                     throws IOException

Throws:

IOException

HTTPRandomAccessFile

public HTTPRandomAccessFile(String url,
                    int bufferSize)
                     throws IOException

Throws:

IOException

Method Detail

close

public void close()
           throws IOException

Description copied from class: RandomAccessFile

Close the file, and release any associated system resources.

Specified by:

close in interface FileCacheable

Overrides:

close in class RandomAccessFile

Throws:

IOException - if an I/O error occurrs.

read_

protected int read_(long pos,
        byte[] buff,
        int offset,
        int len)
             throws IOException

Read directly from file, without going through the buffer. All reading goes through here or readToByteChannel;

Overrides:

read_ in class RandomAccessFile

Parameters:

pos - start here in the file

buff - put data into this buffer

offset - buffer offset

len - this number of bytes

Returns:

actual number of bytes read

Throws:

IOException - on io error

readToByteChannel

public long readToByteChannel(WritableByteChannel dest,
                     long offset,
                     long nbytes)
                       throws IOException

Description copied from class: RandomAccessFile

Read nbytes bytes, at the specified file offset, send to a WritableByteChannel. This will block until all bytes are read. This uses the underlying file channel directly, bypassing all user buffers.

Overrides:

readToByteChannel in class RandomAccessFile

Parameters:

dest - write to this WritableByteChannel.

offset - the offset in the file where copying will start.

nbytes - the number of bytes to read.

Returns:

the actual number of bytes read and transfered

Throws:

IOException - if an I/O error occurs.

length

public long length()
            throws IOException

Description copied from class: RandomAccessFile

Get the length of the file. The data in the buffer (which may not have been written the disk yet) is taken into account.

Overrides:

length in class RandomAccessFile

Returns:

the length of the file in bytes.

Throws:

IOException - if an I/O error occurrs.