Interface XFileAccessor

The XFileAccessor interface is implemented by filesystems that need to be accessed via the XFile API. Classes that implement this interface must be associated with a URL scheme that is structured according to the Common Internet Scheme syntax described in RFC 1738; an optional location part followed by a hierarchical set of slash separated directories.

A class file that implements this interface must be named "XFileAccessor" and be installed in a directory named after the URL scheme that it implements, for instance, an XFileAccessor that provides file access through the HTTP protocol would be associated with the "http" URL and its class file would be called:

http.XFileAccessor

A class prefix is added to this name. The default prefix is com.sun and this composite name is located by the classLoader via the CLASSPATH. For instance, Sun's "nfs" XFileAccessor is installed as:

com.sun.nfs.XFileAccessor

The default class prefix com.sun can be changed by setting the System property java.protocol.xfile to any desired prefix or a list of prefixes separated by vertical bars. Each prefix in the list will be used to construct a package name and the classLoader will attempt to load that package via the CLASSPATH. This process will continue until the XFileAccessor is successfully loaded.

For instance, if you want to use the "ftp" XFileAccessor from Acme, Inc and the "nfs" XFileAccessor from "ABC Inc." then you can set the system property as follows:

java.protocol.xfile=com.acme|com.abc

When an "ftp" URL is used, the following package names will be constructed:

    com.acme.ftp.XFileAccessor
    com.abc.ftp.XFileAccessor
    com.sun.ftp.XFileAccessor
 

(the default "com.sun" prefix is automatically added to the end of the property list)

The class loader attempts to load each of the constructed package names in turn relative to the CLASSPATH until it is successful.

A subsequent reference to an "nfs" URL will result in the following list of candidate package names:

    com.acme.nfs.XFileAccessor
    com.abc.nfs.XFileAccessor
    com.sun.nfs.XFileAccessor
 

In this case the "nfs" XFileAccessor from ABC, Inc. will be loaded in preference to Sun's NFS.

public boolean canRead()

public boolean canWrite()

public void close()
            throws IOException

public boolean delete()

public boolean exists()

public void flush()
            throws IOException

public XFile getXFile()

public boolean isDirectory()

public boolean isFile()

public long lastModified()

public long length()

public String[] list()

public boolean mkdir()

public boolean mkfile()

public boolean open(XFile xf,
                    boolean serial,
                    boolean readOnly)

public int read(b[] ,
                int off,
                int len,
                long foff)
            throws IOException

public boolean renameTo(XFile dest)

public void write(b[] ,
                  int off,
                  int len,
                  long foff)
            throws IOException