// documentation inherited
public void validate() {
if (!_valid) {
// lay ourselves out
layout();
// now validate our children
applyOperation(
new ChildOp() {
public void apply(BComponent child) {
child.validate();
}
});
// finally mark ourselves as valid
_valid = true;
}
}
@Override // from BComponent
public void layout() {
Insets insets = getInsets();
int twidth = getWidth() - insets.getHorizontal();
int theight = getHeight() - insets.getVertical();
int gap = ((GroupLayout) getLayoutManager()).getGap();
// first make sure all of our entries have been measured and
// compute our total height and extent
int totheight = 0;
for (Entry<V, C> entry : _values) {
if (entry.height < 0) {
if (entry.component == null) {
entry.component = createComponent(entry.value);
}
boolean remove = false;
if (!entry.component.isAdded()) {
add(entry.component);
remove = true;
}
entry.height = entry.component.getPreferredSize(twidth, 0).height;
if (remove) {
remove(entry.component);
}
}
totheight += entry.height;
}
if (_values.size() > 1) {
totheight += (gap * _values.size() - 1);
}
int extent = Math.min(theight, totheight);
// if our most recent value was added with _snap then we scroll to
// the bottom on this layout and clear our snappy flag
int value = _snap ? (totheight - extent) : _model.getValue();
_snap = false;
// if our extent or total height have changed, update the model
// (because we're currently invalid, the resulting call to
// invalidate() will have no effect)
if (extent != _model.getExtent() || totheight != _model.getMaximum()) {
_model.setRange(0, value, extent, totheight);
}
// now back up from the last component until we reach the first one
// that's in view
_offset = _model.getValue();
int compIx = 0;
for (int ii = 0; ii < _values.size(); ii++) {
Entry<V, C> entry = _values.get(ii);
if (_offset < entry.height) {
compIx = ii;
break;
}
_offset -= (entry.height + gap);
// remove and clear out the components before our top component
if (entry.component != null) {
if (entry.component.isAdded()) {
remove(entry.component);
}
entry.component = null;
}
}
// compensate for the partially visible topmost component
extent += _offset;
// now add components until we use up our extent
int topIx = compIx;
while (compIx < _values.size() && extent > 0) {
Entry<V, C> entry = _values.get(compIx);
if (entry.component == null) {
entry.component = createComponent(entry.value);
}
if (!entry.component.isAdded()) {
add(compIx - topIx, entry.component);
}
extent -= (entry.height + gap);
compIx++;
}
// lastly remove any components below the last visible component
while (compIx < _values.size()) {
Entry<V, C> entry = _values.get(compIx);
if (entry.component != null) {
if (entry.component.isAdded()) {
remove(entry.component);
}
entry.component = null;
}
compIx++;
}
// now have the layout manager layout our added components
super.layout();
}