public class FTPListParseEngine extends Object
This object defines a two-part parsing mechanism.
The first part is comprised of reading the raw input into an internal
list of strings. Every item in this list corresponds to an actual
file. All extraneous matter emitted by the server will have been
removed by the end of this phase. This is accomplished in conjunction
with the FTPFileEntryParser associated with this engine, by calling
its methods readNextEntry() - which handles the issue of
what delimits one entry from another, usually but not always a line
feed and preParse() - which handles removal of
extraneous matter such as the preliminary lines of a listing, removal
of duplicates on versioning systems, etc.
The second part is composed of the actual parsing, again in conjunction
with the particular parser used by this engine. This is controlled
by an iterator over the internal list of strings. This may be done
either in block mode, by calling the getNext() and
getPrevious() methods to provide "paged" output of less
than the whole list at one time, or by calling the
getFiles() method to return the entire list.
Examples:
Paged access:
FTPClient f=FTPClient();
f.connect(server);
f.login(username, password);
FTPListParseEngine engine = f.initiateListParsing(directory);
while (engine.hasNext()) {
FTPFile[] files = engine.getNext(25); // "page size" you want
//do whatever you want with these files, display them, etc.
//expensive FTPFile objects not created until needed.
}
For unpaged access, simply use FTPClient.listFiles(). That method uses this class transparently.
| Constructor and Description |
|---|
FTPListParseEngine(FTPFileEntryParser parser) |
| Modifier and Type | Method and Description |
|---|---|
FTPFile[] |
getFiles()
Returns an array of FTPFile objects containing the whole list of
files returned by the server as read by this object's parser.
|
FTPFile[] |
getFiles(FTPFileFilter filter)
Returns an array of FTPFile objects containing the whole list of
files returned by the server as read by this object's parser.
|
FTPFile[] |
getNext(int quantityRequested)
Returns an array of at most
quantityRequested FTPFile
objects starting at this object's internal iterator's current position. |
FTPFile[] |
getPrevious(int quantityRequested)
Returns an array of at most
quantityRequested FTPFile
objects starting at this object's internal iterator's current position,
and working back toward the beginning. |
boolean |
hasNext()
convenience method to allow clients to know whether this object's
internal iterator's current position is at the end of the list.
|
boolean |
hasPrevious()
convenience method to allow clients to know whether this object's
internal iterator's current position is at the beginning of the list.
|
void |
readServerList(InputStream stream)
Deprecated.
use
readServerList(InputStream, String) instead |
void |
readServerList(InputStream stream,
String encoding)
handle the initial reading and preparsing of the list returned by
the server.
|
void |
resetIterator()
resets this object's internal iterator to the beginning of the list.
|
public FTPListParseEngine(FTPFileEntryParser parser)
public void readServerList(InputStream stream, String encoding) throws IOException
stream - input stream provided by the server socket.encoding - the encoding to be used for reading the streamIOException - thrown on any failure to read from the sever.public FTPFile[] getNext(int quantityRequested)
quantityRequested FTPFile
objects starting at this object's internal iterator's current position.
If fewer than quantityRequested such
elements are available, the returned array will have a length equal
to the number of entries at and after after the current position.
If no such entries are found, this array will have a length of 0.
After this method is called this object's internal iterator is advanced
by a number of positions equal to the size of the array returned.quantityRequested - the maximum number of entries we want to get.quantityRequested FTPFile
objects starting at the current position of this iterator within its
list and at least the number of elements which exist in the list at
and after its current position.
NOTE: This array may contain null members if any of the individual file listings failed to parse. The caller should check each entry for null before referencing it.
public FTPFile[] getPrevious(int quantityRequested)
quantityRequested FTPFile
objects starting at this object's internal iterator's current position,
and working back toward the beginning.
If fewer than quantityRequested such
elements are available, the returned array will have a length equal
to the number of entries at and after after the current position.
If no such entries are found, this array will have a length of 0.
After this method is called this object's internal iterator is moved
back by a number of positions equal to the size of the array returned.quantityRequested - the maximum number of entries we want to get.quantityRequested FTPFile
objects starting at the current position of this iterator within its
list and at least the number of elements which exist in the list at
and after its current position. This array will be in the same order
as the underlying list (not reversed).
NOTE: This array may contain null members if any of the individual file listings failed to parse. The caller should check each entry for null before referencing it.
public FTPFile[] getFiles() throws IOException
IOException - - not ever thrown, may be removed in a later releasepublic FTPFile[] getFiles(FTPFileFilter filter) throws IOException
filter - FTPFileFilter, must not be null.
NOTE: This array may contain null members if any of the
individual file listings failed to parse. The caller should
check each entry for null before referencing it, or use the
a filter such as FTPFileFilters.NON_NULL which does not
allow null entries.
IOException - - not ever thrown, may be removed in a later releasepublic boolean hasNext()
public boolean hasPrevious()
public void resetIterator()
@Deprecated public void readServerList(InputStream stream) throws IOException
readServerList(InputStream, String) insteadstream - the stream from which to readIOException - on errorCopyright © 2001–2017 The Apache Software Foundation. All rights reserved.