/*
* Ext GWT - Ext for GWT
* Copyright(c) 2007-2009, Ext JS, LLC.
* licensing@extjs.com
*
* http://extjs.com/license
*/
package com.extjs.gxt.ui.client.widget.grid;
import java.util.ArrayList;
import java.util.List;
import com.extjs.gxt.ui.client.GXT;
import com.extjs.gxt.ui.client.data.ModelData;
import com.extjs.gxt.ui.client.event.BaseEvent;
import com.extjs.gxt.ui.client.event.Listener;
import com.extjs.gxt.ui.client.store.ListStore;
import com.extjs.gxt.ui.client.store.Record;
import com.extjs.gxt.ui.client.util.DelayedTask;
import com.google.gwt.dom.client.Element;
import com.google.gwt.dom.client.NodeList;
/**
* Renders the rows as they scroll into view. This GridView is fast for
* displaying many rows at once, but it does not support all features the normal
* {link @GridView} supports, such has expanding rows.
*
* <p />
* Only works with constant row heights that can be specified using
* {@link #setRowHeight(int)}.
*/
public class BufferView extends GridView {
private int rowHeight = 19;
private int cacheSize = 20;
private int cleanDelay = 500;
private DelayedTask cleanTask;
private DelayedTask renderTask;
private int scrollDelay = 100;
private boolean bufferEnabled = true;
/**
* Returns the amount of rows that should be cached.
*
* @return the cache size
*/
public int getCacheSize() {
return cacheSize;
}
/**
* Returns the amount of time before cleaning is done.
*
* @return the clean delay
*/
public int getCleanDelay() {
return cleanDelay;
}
/**
* Returns the height of one row.
*
* @return the height of one row
*/
public int getRowHeight() {
return rowHeight;
}
/**
* Returns the amount of time before new rows are displayed after scrolling
*
* @return the scroll delay
*/
public int getScrollDelay() {
return scrollDelay;
}
/**
* Returns true if buffering is enabled.
*
* @return true for buffering
*/
public boolean isBufferEnabled() {
return bufferEnabled;
}
@Override
public void layout() {
super.layout();
update();
}
/**
* True to enabled buffered functionality (defaults to true).
*
* @param bufferEnabled true to buffer, otherwise false
*/
public void setBufferEnabled(boolean bufferEnabled) {
this.bufferEnabled = bufferEnabled;
}
/**
* Sets the amount of rows that should be cached (default to 10).
*
* @param cacheSize the new cache size
*/
public void setCacheSize(int cacheSize) {
this.cacheSize = cacheSize;
}
/**
* Sets the amount of time before cleaning is done (defaults to 500).
*
* @param cleanDelay the new clean delay
*/
public void setCleanDelay(int cleanDelay) {
this.cleanDelay = cleanDelay;
}
/**
* Sets the height of one row (defaults to 19).
*
* @param rowHeight the new row height.
*/
public void setRowHeight(int rowHeight) {
this.rowHeight = rowHeight;
}
/**
* Sets the amount of time before new rows are displayed after scrolling
* (defaults to 100).
*
* @param scrollDelay the new scroll delay.
*/
public void setScrollDelay(int scrollDelay) {
this.scrollDelay = scrollDelay;
}
// a buffered method to clean rows
protected void clean() {
if (cleanTask == null) {
cleanTask = new DelayedTask(new Listener<BaseEvent>() {
public void handleEvent(BaseEvent be) {
doClean();
}
});
}
cleanTask.delay(cleanDelay);
}
protected void doClean() {
int count = getVisibleRowCount();
if (count > 0) {
int[] vr = getVisibleRows(count);
vr[0] -= cacheSize;
vr[1] += cacheSize;
int i = 0;
NodeList<Element> rows = getRows();
// if first is less than 0, all rows have been rendered
// so lets clean the end...
if (vr[0] <= 0) {
i = vr[1] + 1;
}
for (int len = grid.getStore().getCount(); i < len; i++) {
// if current row is outside of first and last and
// has content, update the innerHTML to nothing
if ((i < vr[0] || i > vr[1])) {
detachWidget(i, true);
rows.getItem(i).setInnerHTML("");
}
}
}
}
@Override
protected String doRender(List<ColumnData> cs, List<ModelData> rows, int startRow, int colCount, boolean stripe) {
if (!bufferEnabled) {
return super.doRender(cs, rows, startRow, colCount, stripe);
}
return doRender(cs, rows, startRow, colCount, stripe, false);
}
protected String doRender(List<ColumnData> cs, List<ModelData> rows, int startRow, int colCount, boolean stripe,
boolean onlyBody) {
int last = colCount - 1;
int rh = getStyleRowHeight();
int[] vr = getVisibleRows(getVisibleRowCount());
String tstyle = "width:" + getTotalWidth() + "px;height:" + rh + "px;";
// buffers
StringBuilder buf = new StringBuilder();
StringBuilder cb = new StringBuilder();
for (int j = 0, len = rows.size(); j < len; j++) {
ModelData model = (ModelData) rows.get(j);
Record r = ds.hasRecord(model) ? ds.getRecord(model) : null;
int rowIndex = (j + startRow);
boolean visible = rowIndex >= vr[0] && rowIndex <= vr[1];
if (visible) {
for (int i = 0; i < colCount; i++) {
ColumnData c = cs.get(i);
c.css = c.css == null ? "" : c.css;
String rv = getRenderedValue(c, rowIndex, i, model, c.name);
String css = (i == 0 ? "x-grid-cell-first " : (i == last ? "x-grid3-cell-last " : " ")) + " "
+ (c.css == null ? "" : c.css);
String attr = c.cellAttr != null ? c.cellAttr : "";
String cellAttr = c.cellAttr != null ? c.cellAttr : "";
if (isShowDirtyCells() && r != null && r.getChanges().containsKey(c.id)) {
css += " x-grid3-dirty-cell";
}
cb.append("<td class=\"x-grid3-col x-grid3-cell x-grid3-td-");
cb.append(c.id);
cb.append(" ");
cb.append(css);
cb.append("\" style=\"");
cb.append(c.style);
cb.append("\" tabIndex=0 ");
cb.append(cellAttr);
cb.append("><div class=\"x-grid3-cell-inner x-grid3-col-");
cb.append(c.id);
cb.append("\" ");
cb.append(attr);
cb.append(">");
cb.append(rv);
cb.append("</div></td>");
}
}
String alt = "";
if (stripe && ((rowIndex + 1) % 2 == 0)) {
alt += " x-grid3-row-alt";
}
if (isShowDirtyCells() && r != null && r.isDirty()) {
alt += " x-grid3-dirty-row";
}
if (viewConfig != null) {
alt += " " + viewConfig.getRowStyle(model, rowIndex, ds);
}
if (visible) {
if (!onlyBody) {
buf.append("<div class=\"x-grid3-row ");
buf.append(alt);
buf.append("\" style=\"");
buf.append(tstyle);
buf.append("\">");
}
buf.append("<table class=x-grid3-row-table border=0 cellspacing=0 cellpadding=0 style=\"");
buf.append(tstyle);
buf.append("\"><tbody><tr>");
buf.append(cb.toString());
buf.append("</tr>");
buf.append((enableRowBody
? ("<tr class=x-grid3-row-body-tr style=\"\"><td colspan=" + colCount + " class=x-grid3-body-cell tabIndex=0><div class=x-grid3-row-body>${body}</div></td></tr>")
: ""));
buf.append("</tbody></table>");
if (!onlyBody) {
buf.append("</div>");
}
} else {
buf.append("<div class=\"x-grid3-row \"");
buf.append(alt);
buf.append("\" style=\"");
buf.append(tstyle);
buf.append("\"></div>");
}
cb = new StringBuilder();
}
return buf.toString();
}
protected void doUpdate() {
int count = getVisibleRowCount();
if (count > 0) {
ColumnModel cm = grid.getColumnModel();
ListStore<ModelData> store = grid.getStore();
List<ColumnData> cs = getColumnData();
boolean stripe = grid.isStripeRows();
int[] vr = getVisibleRows(count);
for (int i = vr[0]; i <= vr[1]; i++) {
// if row is NOT rendered and is visible, render it
if (!isRowRendered(i)) {
List<ModelData> list = new ArrayList<ModelData>();
list.add(store.getAt(i));
String html = doRender(cs, list, i, cm.getColumnCount(), stripe, true);
getRow(i).setInnerHTML(html);
renderWidgets(i, i);
}
}
clean();
}
}
protected int getCalculatedRowHeight() {
return rowHeight + borderWidth;
}
protected int getStyleRowHeight() {
return rowHeight + (GXT.isBorderBox ? borderWidth : 0);
}
protected int getVisibleRowCount() {
int rh = getCalculatedRowHeight();
int visibleHeight = scroller.getHeight(true);
return (int) ((visibleHeight < 1) ? 0 : Math.ceil(((double) visibleHeight / rh)));
}
protected int[] getVisibleRows(int count) {
int sc = scroller.getScrollTop();
int start = (int) (sc == 0 ? 0 : Math.floor(sc / getCalculatedRowHeight()) - 1);
int first = Math.max(start, 0);
int last = Math.min(start + count + 2, grid.getStore().getCount() - 1);
return new int[] {first, last};
}
protected boolean isRowRendered(int index) {
Element row = getRow(index);
return row != null && row.hasChildNodes();
}
@Override
protected void syncScroll() {
super.syncScroll();
update();
}
protected void update() {
if (!bufferEnabled) return;
if (renderTask == null) {
renderTask = new DelayedTask(new Listener<BaseEvent>() {
public void handleEvent(BaseEvent be) {
doUpdate();
}
});
}
renderTask.delay(scrollDelay);
}
}