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 |
---|---|
List<FTPFile> |
getFileList(FTPFileFilter filter)
Returns a list of FTPFile objects containing the whole list of files returned by the server as read by this object's parser.
|
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 inputStream)
Deprecated.
use
readServerList(InputStream, String) instead |
void |
readServerList(InputStream inputStream,
String charsetName)
Reads (and closes) 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 List<FTPFile> getFileList(FTPFileFilter filter)
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.
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 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 boolean hasNext()
public boolean hasPrevious()
@Deprecated public void readServerList(InputStream inputStream) throws IOException
readServerList(InputStream, String)
insteadinputStream
- the stream from which to readIOException
- on errorpublic void readServerList(InputStream inputStream, String charsetName) throws IOException
inputStream
- input stream provided by the server socket.charsetName
- the encoding to be used for reading the streamIOException
- thrown on any failure to read from the sever.public void resetIterator()
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