Represents control data for returning paged results from a search.
Example of usage, with JFC:
// Call this to initialize the list box, whenever the search
// conditions change.
// "filter" may be "objectclass=person", for example
void initListBox( String host, int port, String base, String filter ) {
// Create list box if not already done
if ( _dataList == null ) {
_dataList = new JList();
JScrollPane scrollPane = new JScrollPane(_dataList);
add( scrollPane );
}
// Create a virtual data model
vlistModel model = new vlistModel( host, port, base, filter );
// Keep a buffer of one page before and one after
model.setPageSize( getScrollVisibleSize() );
_dataList.setModel( model );
}
// Data model to supply buffer list data
class vlistModel extends AbstractListModel {
vlistModel( String host, int port, String base, String filter ) {
_base = base;
_filter = filter;
// Connect to the server
try {
_ldc = new LDAPConnection();
System.out.println( "Connecting to " + host +
":" + port );
_ldc.connect( host, port );
} catch ( LDAPException e ) {
System.out.println( e );
_ldc = null;
}
}
// Called by JList to get virtual list size
public int getSize() {
if ( !_initialized ) {
_initialized = true;
_pageControls = new LDAPControl[2];
// Paged results also require a sort control
_pageControls[0] =
new LDAPSortControl( new LDAPSortKey("cn"),
true );
// Do an initial search to get the virtual list size
// Keep one page before and one page after the start
_beforeCount = _pageSize;
_afterCount = _pageSize;
// Create the initial paged results control
LDAPVirtualListControl cont =
new LDAPVirtualListControl( "A",
_beforeCount,
_afterCount );
_pageControls[1] = cont;
_vlc = (LDAPVirtualListControl)_pageControls[1];
getPage( 0 );
}
return _size;
}
// Get a page starting at first (although we may also fetch
// some preceding entries)
boolean getPage( int first ) {
_vlc.setRange( first, _beforeCount, _afterCount );
return getPage();
}
boolean getEntries() {
// Specify necessary controls for vlv
if ( _pageControls != null ) {
try {
_ldc.setOption( _ldc.SERVERCONTROLS, _pageControls );
} catch ( LDAPException e ) {
System.out.println( e + ", setting vlv control" );
}
}
// Empty the buffer
_entries.removeAllElements();
// Do a search
try {
String[] attrs = { "cn" };
LDAPSearchResults result =
_ldc.search( _base,
LDAPConnection.SCOPE_SUB,
_filter,
attrs, false );
while ( result.hasMoreElements() ) {
LDAPEntry entry = (LDAPEntry)result.nextElement();
LDAPAttribute attr = entry.getAttribute( attrs[0] );
if ( attr != null ) {
Enumeration en = attr.getStringValues();
while( en.hasMoreElements() ) {
String name = (String)en.nextElement();
_entries.addElement( name );
}
}
}
} catch ( LDAPException e ) {
System.out.println( e + ", searching" );
return false;
}
return true;
}
// Fetch a buffer
boolean getPage() {
// Get the actual entries
if ( !getEntries() )
return false;
// Check if we have a control returned
LDAPControl[] c = _ldc.getResponseControls();
LDAPVirtualListResponse nextCont = null;
for ( int i = 0; i <32c.length; i++ ) {
if ( c[i] instanceof LDAPVirtualListResponse ) {
nextCont = (LDAPVirtualListResponse)c[i];
break;
}
}
if ( nextCont != null ) {
_selectedIndex = nextCont.getFirstPosition() - 1;
_top = Math.max( 0, _selectedIndex - _beforeCount );
// Now we know the total size of the virtual list box
_size = nextCont.getContentCount();
_vlc.setListSize( _size );
} else {
System.out.println( "Null response control" );
}
return true;
}
// Called by JList to fetch data to paint a single list item
public Object getElementAt(int index) {
if ( (index <32_top) || (index >= _top + _entries.size()) ) {
getPage( index );
}
int offset = index - _top;
if ( (offset <320) || (offset >= _entries.size()) )
return new String( "No entry at " + index );
else
return _entries.elementAt( offset );
}
// Called by application to find out the virutal selected index
public int getSelectedIndex() {
return _selectedIndex;
}
// Called by application to find out the top of the buffer
public int getFirstIndex() {
return _top;
}
public void setPageSize( int size ) {
_pageSize = size;
}
Vector _entries = new Vector();
protected boolean _initialized = false;
private int _top = 0;
protected int _beforeCount;
protected int _afterCount;
private int _pageSize = 10;
private int _selectedIndex = 0;
protected LDAPControl[] _pageControls = null;
protected LDAPVirtualListControl _vlc = null;
protected int _size = -1;
private String _base;
private String _filter;
private LDAPConnection _ldc;
}
VirtualListViewRequest ::= SEQUENCE {
beforeCount INTEGER (0 .. maxInt),
afterCount INTEGER (0 .. maxInt),
CHOICE {
byIndex [0] SEQUENCE {
index INTEGER,
contentCount INTEGER
}
byFilter [1] jumpTo Substring
},
contextID OCTET STRING OPTIONAL
}
LDAPVirtualListControl
public LDAPVirtualListControl(String jumpTo,
int beforeCount,
int afterCount)
Constructs a new LDAPVirtualListControl
object. Use this
constructor on an initial search operation, specifying the first
entry to be matched, or the initial part of it.
jumpTo
- an LDAP search expression defining the result setbeforeCount
- the number of results before the top/center to
return per pageafterCount
- the number of results after the top/center to
return per page
LDAPVirtualListControl
public LDAPVirtualListControl(String jumpTo,
int beforeCount,
int afterCount,
String context)
LDAPVirtualListControl
public LDAPVirtualListControl(int startIndex,
int beforeCount,
int afterCount,
int contentCount)
Constructs a new LDAPVirtualListControl
object. Use this
constructor on a subsquent search operation, after we know the
size of the virtual list, to fetch a subset.
startIndex
- the index into the virtual list of an entry to
returnbeforeCount
- the number of results before the top/center to
return per pageafterCount
- the number of results after the top/center to
return per page
LDAPVirtualListControl
public LDAPVirtualListControl(int startIndex,
int beforeCount,
int afterCount,
int contentCount,
String context)
getAfterCount
public int getAfterCount()
Gets the number of results after the top/center to return per page.
- the number of results after the top/center to return per page.
getBeforeCount
public int getBeforeCount()
Gets the number of results before the top/center to return per page.
- the number of results before the top/center to return per page.
getContext
public String getContext()
Gets the optional context cookie.
- the optional context cookie.
getIndex
public int getIndex()
Gets the size of the virtual result set.
- the size of the virtual result set, or -1 if not known.
getListSize
public int getListSize()
Gets the size of the virtual result set.
- the size of the virtual result set, or -1 if not known.
setContext
public void setContext(String context)
Sets the optional context cookie.
context
- the optional context cookie
setListSize
public void setListSize(int listSize)
Sets the size of the virtual result set.
listSize
- the virtual result set size
setRange
public void setRange(String jumpTo,
int beforeCount,
int afterCount)
Sets the search expression, and the number of entries before and after
to return.
jumpTo
- an LDAP search expression defining the result set
return.beforeCount
- the number of results before startIndex to
return per pageafterCount
- the number of results after startIndex to
return per page
setRange
public void setRange(int startIndex,
int beforeCount,
int afterCount)
Sets the starting index, and the number of entries before and after
to return. Apply this method to a control returned from a previous
search, to specify what result range to return on the next search.
startIndex
- the index into the virtual list of an entry to
returnbeforeCount
- the number of results before startIndex to
return per pageafterCount
- the number of results after startIndex to
return per page
toString
public String toString()
Return a string representation of the control for debugging
- toString in interface LDAPControl
- a string representation of the control.