/*
* Ext GWT 2.2.4 - Ext for GWT
* Copyright(c) 2007-2010, Ext JS, LLC.
* licensing@extjs.com
*
* http://extjs.com/license
*/
package com.extjs.gxt.ui.client.widget.grid;
import com.extjs.gxt.ui.client.GXT;
import com.extjs.gxt.ui.client.Style.SortDir;
import com.extjs.gxt.ui.client.core.El;
import com.extjs.gxt.ui.client.core.XDOM;
import com.extjs.gxt.ui.client.data.ModelData;
import com.extjs.gxt.ui.client.data.ModelKeyProvider;
import com.extjs.gxt.ui.client.data.PagingLoadResult;
import com.extjs.gxt.ui.client.data.PagingLoader;
import com.extjs.gxt.ui.client.event.BaseEvent;
import com.extjs.gxt.ui.client.event.Events;
import com.extjs.gxt.ui.client.event.GridEvent;
import com.extjs.gxt.ui.client.event.Listener;
import com.extjs.gxt.ui.client.event.LiveGridEvent;
import com.extjs.gxt.ui.client.store.ListStore;
import com.extjs.gxt.ui.client.store.Record;
import com.extjs.gxt.ui.client.store.StoreEvent;
import com.extjs.gxt.ui.client.store.StoreListener;
import com.extjs.gxt.ui.client.util.DelayedTask;
import com.google.gwt.dom.client.Element;
import com.google.gwt.user.client.Event;
/**
* LiveGridView for displaying large amount of data. Data is loaded on demand as
* the user scrolls the grid.
*/
public class LiveGridView extends GridView {
protected El liveScroller;
protected ListStore<ModelData> liveStore;
protected int liveStoreOffset = 0;
protected int totalCount = 0;
protected int viewIndex;
private int cacheSize = 200;
private boolean isLoading;
// to prevent flickering
private boolean isMasked;
private StoreListener<ModelData> liveStoreListener;
private int loadDelay = 200;
private PagingLoader<PagingLoadResult<ModelData>> loader;
private int loaderOffset;
private DelayedTask loaderTask;
private double prefetchFactor = .2;
private int rowHeight = 20;
private int viewIndexReload = -1;
/**
* Returns the numbers of rows that should be cached.
*
* @return the cache size
*/
public int getCacheSize() {
int c = -1;
if (grid.isViewReady()) {
c = getVisibleRowCount();
}
return Math.max(c, cacheSize);
}
/**
* Returns the amount of time before loading is done.
*
* @return the load delay in milliseconds
*/
public int getLoadDelay() {
return loadDelay;
}
/**
* Returns the prefetchFactor.
*
* @return the prefetchFactor
*/
public double getPrefetchFactor() {
return prefetchFactor;
}
/**
* Returns the height of one row.
*
* @return the height of one row
*/
public int getRowHeight() {
return rowHeight;
}
public int getVisibleRowCount() {
int rh = getCalculatedRowHeight();
int visibleHeight = getLiveScrollerHeight();
return (int) ((visibleHeight < 1) ? 0 : Math.floor((double) visibleHeight / rh));
}
@SuppressWarnings("rawtypes")
@Override
public void handleComponentEvent(GridEvent ge) {
super.handleComponentEvent(ge);
int type = ge.getEventTypeInt();
Element target = ge.getTarget();
if ((type == Event.ONSCROLL && liveScroller.dom.isOrHasChild(target))
|| (type == Event.ONMOUSEWHEEL && mainBody.dom.isOrHasChild(target))) {
ge.stopEvent();
if (type == Event.ONMOUSEWHEEL) {
int v = ge.getEvent().getMouseWheelVelocityY() * getCalculatedRowHeight();
liveScroller.setScrollTop(liveScroller.getScrollTop() + v);
} else {
updateRows((int) Math.ceil((double) liveScroller.getScrollTop() / getCalculatedRowHeight()), false);
}
}
}
/**
* Refreshed the view. Reloads the store based on the current settings
*/
public void refresh() {
loadLiveStore(liveStoreOffset);
}
@Override
public void refresh(boolean headerToo) {
super.refresh(headerToo);
if (headerToo) {
positionLiveScroller();
}
if (!preventScrollToTopOnRefresh) {
// we scrolled to the top
updateRows(0, false);
}
}
@Override
public void scrollToTop() {
liveScroller.setScrollTop(0);
}
/**
* Sets the amount of rows that should be cached (default to 200). The cache
* size is the number of rows that are retrieved each time a data request is
* made. The cache size should always be greater than the number of visible
* rows of the grid. The number of visible rows will vary depending on the
* grid height and the height of each row. If the set cache size is smaller
* than the number of visible rows of the grid than it gets set to the number
* of visible rows of the grid.
*
* @param cacheSize the new cache size
*/
public void setCacheSize(int cacheSize) {
this.cacheSize = cacheSize;
}
/**
* Sets the amount of time before loading is done (defaults to 200).
*
* @param loadDelay the new load delay in milliseconds
*/
public void setLoadDelay(int loadDelay) {
this.loadDelay = loadDelay;
}
/**
* Sets the pre-fetch factor (defaults to .2). The pre-fetch factor is used to
* determine when new data should be fetched as the user scrolls the grid. The
* factor is used with the cache size.
*
* <p />
* For example, if the cache size is 1000 with a pre-fetch of .20, the grid
* will request new data when the 800th (1000 * .20) row of the grid becomes
* visible.
*
* @param prefetchFactor the pre-fetch factor
*/
public void setPrefetchFactor(double prefetchFactor) {
this.prefetchFactor = prefetchFactor;
}
/**
* Sets the height of one row (defaults to 20). <code>LiveGridView</code> will
* only work with fixed row heights with all rows being the same height.
* Changing this value will not physically resize the row heights, rather, the
* specified height will be used internally for calculations.
*
* @param rowHeight the new row height.
*/
public void setRowHeight(int rowHeight) {
this.rowHeight = rowHeight;
}
@Override
protected void afterRender() {
mainBody.setInnerHtml(renderRows(0, -1));
renderWidgets(0, -1);
processRows(0, true);
applyEmptyText();
refresh();
}
@Override
protected void calculateVBar(boolean force) {
if (force) {
layout();
}
}
@SuppressWarnings({"rawtypes", "unchecked"})
protected GridEvent<?> createComponentEvent(Event event) {
LiveGridEvent l = new LiveGridEvent(grid, event);
l.setLiveStoreOffset(liveStoreOffset);
l.setViewIndex(viewIndex);
l.setTotalCount(totalCount);
return l;
}
protected void doLoad() {
loader.load(loaderOffset, getCacheSize());
}
protected int getCalculatedRowHeight() {
return rowHeight + borderWidth;
}
protected int getLiveScrollerHeight() {
return liveScroller.getHeight(true);
}
protected int getLiveStoreCalculatedIndex(int index) {
int calcIndex = index - (getCacheSize() / 2) + getVisibleRowCount();
calcIndex = Math.min(totalCount - getCacheSize(), calcIndex);
calcIndex = Math.min(index, calcIndex);
return Math.max(0, calcIndex);
}
@Override
protected int getScrollAdjust() {
return scrollOffset;
}
@SuppressWarnings({"unchecked", "rawtypes"})
protected void initData(ListStore ds, ColumnModel cm) {
if (liveStoreListener == null) {
liveStoreListener = new StoreListener<ModelData>() {
public void storeDataChanged(StoreEvent<ModelData> se) {
liveStoreOffset = loader.getOffset();
if (totalCount != loader.getTotalCount()) {
totalCount = loader.getTotalCount();
int height = totalCount * getCalculatedRowHeight();
// 1000000 as browser maxheight hack
int count = height / 1000000;
int h = 0;
StringBuilder sb = new StringBuilder();
if (count > 0) {
h = height / count;
for (int i = 0; i < count; i++) {
sb.append("<div style=\"height:");
sb.append(h);
sb.append("px;\"> </div>");
}
}
int diff = height - count * h;
if (diff != 0) {
sb.append("<div style=\"height:");
sb.append(diff);
sb.append("px;\"></div>");
}
liveScroller.setInnerHtml(sb.toString());
}
if (totalCount > 0 && viewIndexReload != -1 && !isCached(viewIndexReload)) {
loadLiveStore(getLiveStoreCalculatedIndex(viewIndexReload));
} else {
viewIndexReload = -1;
updateRows(viewIndex, true);
isLoading = false;
if (isMasked) {
isMasked = false;
scroller.unmask();
}
}
}
public void storeUpdate(StoreEvent<ModelData> se) {
LiveGridView.this.ds.update(se.getModel());
}
};
}
if (liveStore != null) {
liveStore.removeStoreListener(liveStoreListener);
}
liveStore = ds;
super.initData(new ListStore() {
@Override
public boolean equals(ModelData model1, ModelData model2) {
return LiveGridView.this.liveStore.equals(model1, model2);
}
@Override
public ModelKeyProvider getKeyProvider() {
return LiveGridView.this.liveStore.getKeyProvider();
}
@Override
public Record getRecord(ModelData model) {
return LiveGridView.this.liveStore.getRecord(model);
}
@Override
public boolean hasRecord(ModelData model) {
return LiveGridView.this.liveStore.hasRecord(model);
}
@Override
public void sort(String field, SortDir sortDir) {
LiveGridView.this.liveStore.sort(field, sortDir);
sortInfo = liveStore.getSortState();
}
}, cm);
loader = (PagingLoader) liveStore.getLoader();
liveStore.addStoreListener(liveStoreListener);
grid.getSelectionModel().bind(this.ds);
}
protected boolean isCached(int index) {
if ((liveStore.getCount() == 0) || (index < liveStoreOffset)
|| (index > (liveStoreOffset + getCacheSize() - getVisibleRowCount()))) {
return false;
}
return true;
}
protected boolean isHorizontalScrollBarShowing() {
return cm.getTotalWidth() > scroller.getStyleWidth();
}
protected boolean loadLiveStore(int offset) {
if (loaderTask == null) {
loaderTask = new DelayedTask(new Listener<BaseEvent>() {
public void handleEvent(BaseEvent be) {
doLoad();
}
});
}
loaderOffset = offset;
loaderTask.delay(loadDelay);
if (isLoading) {
return true;
} else {
isLoading = true;
return false;
}
}
@Override
protected void notifyShow() {
super.notifyShow();
updateRows(viewIndex, true);
}
@Override
protected void onColumnWidthChange(int column, int width) {
super.onColumnWidthChange(column, width);
updateRows(viewIndex, false);
}
@Override
protected void onRemove(ListStore<ModelData> ds, ModelData m, int index, boolean isUpdate) {
super.onRemove(ds, m, index, isUpdate);
if (!isUpdate && liveStore.hasRecord(m)) {
liveStore.getRecord(m).reject(false);
}
}
@Override
protected void renderUI() {
super.renderUI();
scroller.setStyleAttribute("overflowY", "hidden");
liveScroller = grid.el().insertFirst("<div class=\"x-livegrid-scroller\"></div>");
positionLiveScroller();
liveScroller.addEventsSunk(Event.ONSCROLL);
mainBody.addEventsSunk(Event.ONMOUSEWHEEL);
}
@Override
protected void resize() {
int oldCount = getVisibleRowCount();
super.resize();
if (mainBody != null) {
int h = grid.getHeight(true) - mainHd.getHeight(true);
if (isHorizontalScrollBarShowing()) {
h -= XDOM.getScrollBarWidth();
}
if (footer != null) {
h -= footer.getHeight();
}
liveScroller.setHeight(h, true);
scroller.setWidth(grid.getWidth() - getScrollAdjust(), true);
if (oldCount != getVisibleRowCount()) {
updateRows(viewIndex, true);
}
}
}
protected boolean shouldCache(int index) {
int cz = getCacheSize();
int i = (int) (cz * prefetchFactor);
double low = liveStoreOffset + i;
double high = liveStoreOffset + cz - getVisibleRowCount() - i;
if ((index < low && liveStoreOffset > 0) || (index > high && liveStoreOffset != totalCount - cz)) {
return true;
}
return false;
}
@SuppressWarnings("unchecked")
protected void updateRows(int newIndex, boolean reload) {
int rowCount = getVisibleRowCount();
newIndex = Math.min(newIndex, Math.max(0, totalCount - rowCount));
int diff = newIndex - viewIndex;
int delta = Math.abs(diff);
// nothing has changed and we are not forcing a reload
if (delta == 0 && !reload) {
return;
}
viewIndex = newIndex;
int liveStoreIndex = Math.max(0, viewIndex - liveStoreOffset);
// load data if not already cached
if (!isCached(viewIndex)) {
if (!isMasked && grid.isLoadMask()) {
scroller.mask(GXT.MESSAGES.loadMask_msg());
isMasked = true;
}
if (loadLiveStore(getLiveStoreCalculatedIndex(viewIndex))) {
viewIndexReload = viewIndex;
}
return;
}
// do pre caching
if (shouldCache(viewIndex) && !isLoading) {
loadLiveStore(getLiveStoreCalculatedIndex(viewIndex));
}
int rc = getVisibleRowCount();
if (delta > rc - 1) {
reload = true;
}
if (reload) {
delta = diff = rc;
boolean p = preventScrollToTopOnRefresh;
preventScrollToTopOnRefresh = true;
ds.removeAll();
preventScrollToTopOnRefresh = p;
}
if (delta == 0) {
return;
}
int count = ds.getCount();
if (diff > 0) {
// rolling forward
for (int c = 0; c < delta && c < count; c++) {
ds.remove(0);
}
count = ds.getCount();
ds.add(liveStore.getRange(liveStoreIndex + count, liveStoreIndex + count + delta - 1));
} else {
// rolling back
for (int c = 0; c < delta && c < count; c++) {
ds.remove(count - c - 1);
}
ds.insert(liveStore.getRange(liveStoreIndex, liveStoreIndex + delta - 1), 0);
}
LiveGridEvent<ModelData> event = (LiveGridEvent<ModelData>) createComponentEvent(null);
fireEvent(Events.LiveGridViewUpdate, event);
}
protected void positionLiveScroller() {
liveScroller.setTop(mainHd.getHeight());
}
}