ucar.unidata.io.http
Class HTTPRandomAccessFile

java.lang.Object
  ucar.unidata.io.RandomAccessFile
      ucar.unidata.io.http.HTTPRandomAccessFile

All Implemented Interfaces:

java.io.DataInput, java.io.DataOutput

public class HTTPRandomAccessFile
extends RandomAccessFile

Gives access to files over HTTP, using jakarta commons HttpClient library. 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

Field Summary

static int

defaultHTTPBufferSize

Fields inherited from class ucar.unidata.io.RandomAccessFile

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

Constructor Summary

HTTPRandomAccessFile(java.lang.String url)

HTTPRandomAccessFile(java.lang.String url, int bufferSize)

Method Summary

void	close() Close the file, and release any associated system resources.
java.io.FileDescriptor	getFD() Returns the opaque file descriptor object associated with this file.
static org.apache.commons.httpclient.HttpClient	getHttpClient() Get the HttpClient object - a single instance is used.
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(java.nio.channels.WritableByteChannel dest, long offset, long nbytes) Read up to nbytes bytes, at a specified offset, send to a WritableByteChannel.
static void	setHttpClient(org.apache.commons.httpclient.HttpClient client) Set the HttpClient object - a single instance is used.

Methods inherited from class ucar.unidata.io.RandomAccessFile

flush, getDebugLeaks, getFilePointer, getLocation, getOpenFiles, getRandomAccessFile, isAtEndOfFile, 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, setDebugAccess, setDebugLeaks, setExtendMode, setMinLength, 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(java.lang.String url)
                     throws java.io.IOException

Throws:

java.io.IOException

HTTPRandomAccessFile

public HTTPRandomAccessFile(java.lang.String url,
                            int bufferSize)
                     throws java.io.IOException

Throws:

java.io.IOException

Method Detail

setHttpClient

public static void setHttpClient(org.apache.commons.httpclient.HttpClient client)

Set the HttpClient object - a single instance is used.

Parameters:

client - the HttpClient object

getHttpClient

public static org.apache.commons.httpclient.HttpClient getHttpClient()

Get the HttpClient object - a single instance is used.

Returns:

client the HttpClient object

read_

protected int read_(long pos,
                    byte[] buff,
                    int offset,
                    int len)
             throws java.io.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:

java.io.IOException - on io error

readToByteChannel

public long readToByteChannel(java.nio.channels.WritableByteChannel dest,
                              long offset,
                              long nbytes)
                       throws java.io.IOException

Description copied from class: RandomAccessFile

Read up to nbytes bytes, at a specified 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, or -1 if there is no more data due to the end of the file being reached.

Throws:

java.io.IOException - if an I/O error occurs.

length

public long length()
            throws java.io.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:

java.io.IOException - if an I/O error occurrs.

close

public void close()

Description copied from class: RandomAccessFile

Close the file, and release any associated system resources.

Overrides:

close in class RandomAccessFile

getFD

public java.io.FileDescriptor getFD()

Description copied from class: RandomAccessFile

Returns the opaque file descriptor object associated with this file.

Overrides:

getFD in class RandomAccessFile

Returns:

the file descriptor object associated with this file.