ColumnSortList can grow indefintely, but some users would like to have only a
limited number of entries within it (usually just one). In such cases it will
reduce the need to call clear() before push(...), reducing the number of header
refresh calls. Adding a new limit field and maintaining the list size according
the limit solves this issue with little overhead.
Review at http://gwt-code-reviews.appspot.com/1625803
Review by: jlabanca@google.com
git-svn-id: https://google-web-toolkit.googlecode.com/svn/trunk@10826 8db76d5a-ed1c-0410-87a9-c151d255dfc7
diff --git a/user/src/com/google/gwt/user/cellview/client/ColumnSortList.java b/user/src/com/google/gwt/user/cellview/client/ColumnSortList.java
index 591eddd..ad66230 100644
--- a/user/src/com/google/gwt/user/cellview/client/ColumnSortList.java
+++ b/user/src/com/google/gwt/user/cellview/client/ColumnSortList.java
@@ -121,6 +121,12 @@
private final List<ColumnSortInfo> infos = new ArrayList<ColumnSortInfo>();
/**
+ * This limit prevents the infos list to grow over a given size. The default value (0) means
+ * that the size can grow indefinitely.
+ */
+ private int limit = 0;
+
+ /**
* Construct a new {@link ColumnSortList} without a {@link Delegate}.
*/
public ColumnSortList() {
@@ -172,6 +178,15 @@
return infos.get(index);
}
+ /**
+ * Get the actual limit value
+ *
+ * @return the actual limit value
+ */
+ public int getLimit() {
+ return limit;
+ }
+
@Override
public int hashCode() {
return 31 * infos.hashCode() + 13;
@@ -201,6 +216,17 @@
i--;
}
}
+
+ if (limit > 0) {
+ // at this point, infos.size() must not exceed the limit, a simple condition check is enough
+ if (limit == infos.size()) {
+ infos.remove(infos.size() - 1);
+ }
+ // by the contract of the limit, inserting after the limit must not be allowed
+ if (index >= limit) {
+ throw new IndexOutOfBoundsException("Index: " + index + ", Limit: " + limit);
+ }
+ }
// Insert the new sort info
infos.add(index, sortInfo);
@@ -253,6 +279,31 @@
}
/**
+ * Set the limit to a positive value to prevent the growth of the infos list over the given size.
+ * This method will check if the actual infos list is over the limit, and it will fire the
+ * delegate in the case it should remove items from the list.
+ *
+ * The default value (0) means the size can grow indefinitely.
+ *
+ * @param limit the new limit value
+ */
+ public void setLimit(int limit) {
+ this.limit = limit;
+
+ if (limit > 0) {
+ // checking the list size, as it might have been populated over the limit
+ boolean modified = false;
+ while (limit < infos.size()) {
+ infos.remove(infos.size() - 1);
+ modified = true;
+ }
+ if (modified) {
+ fireDelegate();
+ }
+ }
+ }
+
+ /**
* Get the size of the list.
*
* @return the number of {@link ColumnSortInfo} in the list
