Java Utililty Methods JScrollBar

List of utility methods to do JScrollBar

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JScrollBar

Description

The list of methods to do JScrollBar are organized into topic(s).

Method

boolean isPaintRequiredFor(javax.swing.JScrollBar jScrollBar)
is Paint Required For

if (jScrollBar != null) {
 return (jScrollBar.getMinimum() != jScrollBar.getValue())
 || (jScrollBar.getMaximum() != jScrollBar.getVisibleAmount());
} else {
 return false;

void scrollByBlock(JScrollBar scrollbar, int direction)
scroll By Block

int oldValue = scrollbar.getValue();
int blockIncrement = scrollbar.getBlockIncrement(direction);
int delta = blockIncrement * ((direction > 0) ? +1 : -1);
int newValue = oldValue + delta;
if (delta > 0 && newValue < oldValue) {
 newValue = scrollbar.getMaximum();
} else if (delta < 0 && newValue > oldValue) {
 newValue = scrollbar.getMinimum();
...

void scrollByUnits(JScrollBar scrollbar, int direction, int units, boolean limitToBlock)
scroll By Units

int delta;
int limit = -1;
if (limitToBlock) {
 if (direction < 0) {
 limit = scrollbar.getValue() - scrollbar.getBlockIncrement(direction);
 } else {
 limit = scrollbar.getValue() + scrollbar.getBlockIncrement(direction);
for (int i = 0; i < units; i++) {
 if (direction > 0) {
 delta = scrollbar.getUnitIncrement(direction);
 } else {
 delta = -scrollbar.getUnitIncrement(direction);
 int oldValue = scrollbar.getValue();
 int newValue = oldValue + delta;
 if (delta > 0 && newValue < oldValue) {
 newValue = scrollbar.getMaximum();
 } else if (delta < 0 && newValue > oldValue) {
 newValue = scrollbar.getMinimum();
 if (oldValue == newValue) {
 break;
 if (limitToBlock && i > 0) {
 assert limit != -1;
 if ((direction < 0 && newValue < limit) || (direction > 0 && newValue > limit)) {
 break;
 scrollbar.setValue(newValue);