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tree.js
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tree.js
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var KEY_ENTER=0x0D;
var KEY_END = 0x23;
var KEY_HOME = 0x24;
var KEY_LEFT = 0x25;
var KEY_UP = 0x26;
var KEY_RIGHT = 0x27;
var KEY_DOWN = 0x28;
var ROLE_TREEITEM = "treeitem";
var ROLE_TREE = "tree";
var ROLE_GROUP = "group";
var STATE_EXPANDED = "aria-expanded";
/******************* Begin generic helper functions ****************/
/* @method public getTarget() - helper function to extract the element which fired the event from the event object.
* @param event - event object
* @return - the appropriate target based on the varibles supported in the event object.
*/
function getTarget(event) {
var target = null;
if (event.target) {
target = event.target;
}
else if (event.srcElement) {
target = event.srcElement;
}
return target;
}
var DEBUG = true;
/* @method public debugOut() - helper function to use the dump() command to send information to the dump window in Firefox
* or to use alert() where dump() is not supported. To enable the console window in Firefox start FF with the command line option
* "-console". Also, set the about:config option "browser.dom.window.dump.enabled" to true.
* @param debugStr - the string to output.
*/
var DEBUG = true; // turn on and off output of debugging strings
function debugOut(debugStr) {
if (DEBUG) {
if (window.dump) {
dump(debugStr + "\n");
}
else if (alert) {
alert(debugStr);
}
}
}
/********************* End generic helper functions ****************/
COLLAPSE = "img/minus.gif";
EXPAND= "img/plus.gif";
var TEXT_NODE=3; // IE does not recognize Node.TEXT_NODE nor nodeObj.TEXT_NODE so need to define
/* public isText() - helper function to determine if a particular node is a TEXT_NODE or not.
* Generally text nodes are ignored.
* @param node - the node to test
* @return boolean - true if node is a node.TEXT_NODE, false otherwise
*/
function getRole(node)
{
try {
var role = node.getAttribute("role");
return role ? role : "";
} catch(ex) {
return "";
}
};
function isText(node)
{
return node && node.nodeType == TEXT_NODE;
};
/* @method public isGroupClosed() - function to determine if a treeitem is expanded or collapsed.
* @param groupItem - DOM object representing the treeitem
* @return boolean - true is the item is NOT expanded; false if IS expanded.
*/
function isGroupClosed(groupItem)
{
var treeItemForGroup = getRelativeTreeItem(groupItem, -1, false);
return !treeItemForGroup || treeItemForGroup.getAttribute("aria-expanded") == 'false';
};
/* @method public getFirstTreeItem() - find the first item in the tree
* @param tree - the Tree object
* @return - the first treeitem or null;
*/
function getFirstTreeItem(tree)
{
var first = tree.firstChild;
var treeItem = null;
// FF reports firstChild as text node while IE does not
while (first && isText(first) ) {
first = first.nextSibling; // tree had better have a child that is not text!
}
if (first && first.childNodes) {
for (var i=0; i<first.childNodes.length; i++) {
if (getRole(first.childNodes[i]) == ROLE_TREEITEM) {
treeItem = first.childNodes[i];
break;
}
}
}
return treeItem;
};
/* @method public getLastTreeITem - finds the last item in the tree
* @param tree - the tree object
* @return - the last treeitem
* If the tree has any expandable nodes, the children will be in <divs> that are marked as groups.
* Thus, the last child of the tree might be a group node that also has children.
*/
function getLastTreeItem(tree)
{
var lastTreeItem = tree;
do {
lastTreeItem = lastTreeItem.lastChild;
if (isText(lastTreeItem)) {
lastTreeItem = lastTreeItem.previousSibling;
}
}
while (getRole(lastTreeItem) == ROLE_GROUP);
return getTreeItemFromPar(lastTreeItem);
};
/* @method public getRelativeTreeItem()
* This function finds the next relative tree item in the hierarchy. It uses the structure of the HTML to determine
* the next relative item. The current structure is:
*each treeitem is a span within a div:
<div><span treeitem /></div>
*expandable nodes also contain an img within the div:
<div><img expand/collapse /><span treeitem1 /></div>
*childnodes are grouped within a div with role=group:
<div group><div><span treeitem1.1 /></div><div><span treeitem1.2 /></div></div>
* @param treeitem: div object (may be parent of treeItem span or group div)
* @param delta: -1=previous; 1=next
* @param wrap: true = wrap the searches; false = do not wrap when reach top or bottom
* @ returns the actual treeitem span object
*/
function getRelativeTreeItem(treeItem, delta, wrap)
{
// treeItem is really the parent div of the treeItem
// delta: -1 = prev, 1 = next
if (delta == 1) { // Next
var newTreeItem = treeItem.nextSibling;
while (isText(newTreeItem)) {
newTreeItem = newTreeItem.nextSibling;
}
// if(newTreeItem)
// debugOut(newTreeItem.id + " " + getRole(newTreeItem) );
var treeItemSpan = null;
if (newTreeItem) {
var role = getRole(newTreeItem);
if (role == ROLE_GROUP) {
if (isGroupClosed(newTreeItem)) {
return getRelativeTreeItem(newTreeItem, 1, wrap);
} // end of closed group
else {
newTreeItem = newTreeItem.firstChild;
if (isText(newTreeItem)) {
newTreeItem = newTreeItem.nextSibling;
}
} // end of open group
} // end of if group
if (newTreeItem && treeItemSpan == null) {
//extract the actual treeItem span from the div
for(var i=0; i < newTreeItem.childNodes.length; i++ ) {
treeItemSpan = newTreeItem.childNodes[i]; //debugOut(treeItemSpan.tagName + " " + getRole(treeItemSpan) + "\n");
if (treeItemSpan.nodeName == "SPAN" && getRole(treeItemSpan) == ROLE_TREEITEM) {
return treeItemSpan;
}
}
}
} // end of if newTreeItem
} // end of next
else { // Prev
var newTreeItem = treeItem.previousSibling;
if (isText(newTreeItem)) {
newTreeItem = newTreeItem.previousSibling;
}
if (newTreeItem) {
var role;
while ((role = getRole(newTreeItem)) == ROLE_GROUP) {
if (isGroupClosed(newTreeItem)) {
return getRelativeTreeItem(newTreeItem, -1, wrap);
} // end of if closed group
else {
newTreeItem = newTreeItem.lastChild;
if (isText(newTreeItem)) {
newTreeItem = newTreeItem.previousSibling;
}
} // end of open group
} // end of while
if (newTreeItem && treeItemSpan == null) {
//extract the actual treeItem span from the div
for(var j=0; j < newTreeItem.childNodes.length; j++ ) {
treeItemSpan = newTreeItem.childNodes[j];
if (treeItemSpan.nodeName == "SPAN" && getRole(treeItemSpan) == ROLE_TREEITEM) {
return treeItemSpan;
}
}
}
} // end of if newTreeItem
} // end of prev
if (getRole(treeItem.parentNode) == ROLE_TREE) {
if (!wrap) {
return null;
}
var tree = getTree(treeItem)
return (delta == 1)? getFirstTreeItem(tree) : getLastTreeItem(tree);
}
return getRelativeTreeItem(treeItem.parentNode, delta, wrap); // Recursive
};
/* @method public getTree() - given a treeitem object, find the parent tree.
* @param treeItem - the object with role of treeitem.
* @return - the tree object or null if not found.
* Searches the parent hierarchy until an object with role== tree is found.
*/
function getTree(treeItem)
{
var tree = treeItem;
try {
while (getRole(tree) != ROLE_TREE) {
tree = tree.parentNode;
}
} catch(ex) {
debugOut("error in getTree(); " + ex.message);
return null; // No tree container for tree item
}
return tree;
};
var gNewFocus; // global variable of the item to receive focus
/* @method public setFocus() - uses setTimout to set focus to the specified item.
* @param newFocus - object to call focus() method on
* This method is needed in order to queue the focus to an item during an event handler.
*/
function setFocus(newFocus)
{
if (newFocus) {
gNewFocus = newFocus; // must store in a global variable so object is available when setTimeout occurs.
setTimeout("gNewFocus.focus();", 0);
}
};
/* @method public treeItemEvent - main event handler for capturing key movements.
* @param event - event object
* @returns boolean on whether to propagate (true) or consume (false) the event.
* Event handlers are set on the tree object and thus there is some special casing for images and other objects within
* the tree that are not treeitems.
*/
function treeItemEvent(event)
{ // debugOut(event.type + " : " + event.keyCode);
var treeItem = getTarget(event); //event.target;
if (treeItem.tagName.toLowerCase() == "img") {
var tree = getTree(treeItem);
// get the treeItem from tree.lastFocus
if (tree.lastFocus == "undefined") {
tree.lastFocus = getFirstTreeItem(tree);
}
treeItem = tree.lastFocus;
}
var hasChildren = treeItem.getAttribute("aria-expanded");
var isItemOpen = hasChildren && hasChildren == 'true';
var focusDelta = 0; // (-1 = up, 0 = no change, 1 = down)
var toggleitem = false;
if (event.type == "dblclick" && event.button == 0) {
toggleitem = hasChildren;
getTree(treeItem)._incrementalString = "";
}
else if (event.type == "keydown") {
if (event.altKey) {
return true; // Browser should use this, the tree view doesnot need alt-modified keys
}
// XXX Implement multiple selection (ctrl+arrow, shift+arrow, ctrl+space)
if (event.keyCode == KEY_HOME) {
try {
treeItemFocus(getFirstTreeItem(getTree(treeItem)),true);
} catch(ex) { }
debugOut(ex);
return false;
}
if (event.keyCode == KEY_ENTER) {
toggleitem = hasChildren;
}
else if (event.keyCode == KEY_DOWN) {
focusDelta = 1;
}
else if (event.keyCode == KEY_UP) {
focusDelta = -1;
}
else if (event.keyCode == KEY_LEFT) {
if (isItemOpen) {
toggleitem = true;
}
else {
var groupItem = treeItem.parentNode.parentNode; // relies on treeitems being spans nested in divs
if (getRole(groupItem) == ROLE_GROUP) {
var nextItem = getRelativeTreeItem(groupItem, -1, false);
treeItemFocus(nextItem, true);
}
}
}
else if (event.keyCode == KEY_RIGHT) {
if (isItemOpen) {
focusDelta = 1;
}
else {
toggleitem = hasChildren;
}
}
else if (event.keyCode == KEY_END) {
try {
var newTreeItemFocus = getLastTreeItem(getTree(treeItem));
treeItemFocus(newTreeItemFocus,true);
} catch(ex) { }
debugOut(ex);
return false; // Consume the event
}
else {
return true; // We didn't need key, don't consume event
}
}
else if (event.type == "keypress") {
// Implement incremental find here, instead of keydown, because we
// need to capture printable characters in a keypress handler
var tree = getTree(treeItem);
tree._incrementalString = "";
var key;
if (event.charCode) {
key = event.charCode;
}
else {
key = event.keyCode; // IE uses keyCode - for keypress event the value should be the same as event.charCode
}
if (key > 32 && !event.altKey && !event.ctrlKey &&
!event.shiftKey && !event.metaKey) {
key = String.fromCharCode(key);
}
else {
tree._incrementalString = "";
return true;
}
key = key.toLowerCase();
if (event.timeStamp - tree._lastKeyTime > 1000) {
tree._incrementalString = key;
}
else {
// IE does not have event.timeStamp so will always end up in this else in IE
tree._incrementalString += key;
}
tree._lastKeyTime = event.timeStamp;
var length = tree._incrementalString.length;
var incrementalString = tree._incrementalString;
var charIndex = 1;
while (charIndex < length && incrementalString[charIndex] == incrementalString[charIndex - 1])
charIndex++;
// If all letters in incremental string are same, just try to match the first one
if (charIndex == length) {
length = 1;
incrementalString = incrementalString.substring(0, length);
}
var origTreeItem = treeItem;
if (length == 1) {
treeItem = getRelativeTreeItem(treeItem.parentNode, 1, true);
}
do {
var text = treeItem.firstChild.data;
if (treeItem.firstChild.data.substring(0, length).toLowerCase() == incrementalString) {
treeItemFocus(treeItem, true);
return false;
}
treeItem = getRelativeTreeItem(treeItem.parentNode, 1, true);
} while (treeItem != origTreeItem);
return false;
}
else if (event.type == "click") {
getTree(treeItem)._incrementalString = '';
}
else {
return true; // continue propagating event;
}
if (toggleitem) {
toggleExpandCollapse(treeItem, isItemOpen);
return false; // consume event
}
if (focusDelta) {
//try {
// treeitem is a span, must pass parent div to getRelativeTreeItem();
var nextItem = getRelativeTreeItem(treeItem.parentNode, focusDelta, false);
if (nextItem) {
treeItemFocus(nextItem, true);
}
//} catch(ex) { debugOut("error in focusDelta " + ex.message); }
return false;
}
return true; // Browser can still use event
};
/* @method treeItemClick() is the event handler for clicks inside of the tree. The item clicked upon receives focus.
* @param event - the event object
* @return boolean - true to propagate the event, false to consume it
*/
function treeItemClick(event) {
var treeItem = getTarget(event);
bEventContinue = true;
if (isValidTreeItem(treeItem) ) {
// only process if click was on an actual tree item
treeItemFocus(treeItem, false); // update the tabindex and lastFocused variables, item already has focus from being clicked upon
bEventContinue = false;
}
else {
if (treeItem.tagName.toLowerCase() != "img") {
//reset focus to existing treeItem (can always find Tree from any child)
var curTreeItem = getTree(treeItem).lastFocus;
if (curTreeItem)
setFocus(curTreeItem);
bEventContinue = false;
}
// else not image so return true - only images are for expand/collapse which have their own event handler
}
return bEventContinue;
};
/* @method isValidTreeItem() - determines if object is actually a tree item
* @param treeItem - the possible tree item object
* @return boolean true if is an object with role of treeitem; false if not
*/
function isValidTreeItem(treeItem)
{
var bIsTreeItem = false;
var testItem = treeItem;
if (isText(testItem)) {
testItem = testItem.nextSibling;
}
if (getRole(testItem) == ROLE_TREEITEM ) {
bIsTreeItem = true;
}
return bIsTreeItem;
};
/* @method public treeItemFocus - caches the last focus item on the tree and set the appropriate style and tabindex.
* Updates the style and tabindex of the previously focused treeitem.
* @param treeItem - the tree item to receive focus
* @param bFocus - whether or not to actually set focus to the item. In cases where this is called from a click handler there
* is no need to set focus because the click has set the focus.
*/
function treeItemFocus(treeItem, bFocus)
{
// Cache last focused tree item on the tree
// The last focused item is always the only item in the tab order for this tree,
// so we need to set its tabindex to 0, and the others to -1
// var treeItem = getTarget(event);
var tree = getTree(treeItem);
if (typeof tree.lastFocus == "undefined") {
tree.lastFocus = getFirstTreeItem(tree); //debugOut(tree.lastFocus.firstChild.nodeValue);
}
tree.lastFocus.tabIndex = "-1";
tree.lastFocus.className="treeitem";
tree.lastFocus = treeItem;
treeItem.tabIndex = "0";
treeItem.className="treeitemfocus";
if (bFocus == true) {
setFocus(treeItem);
}
};
/* @method toggleExpandCollaps() - toggles expand and collapse of the node.
* Called from imgToggle() or keyboard event handlers.
* @parm treeItem - object to check for expand/collapse capability
*/
function toggleExpandCollapse(treeItem, isItemOpen)
{
treeItem.setAttribute("aria-expanded", isItemOpen? "false" : "true");
var image = treeItem.previousSibling;
if (isText(image)) {
image = image.previousSibling;
}
var group = treeItem.parentNode
group = group.nextSibling;
if (isText(group)) {
group = group.nextSibling;
}
if (!isItemOpen) {
image.src = COLLAPSE;
group.className="group"; //treeitem is span within div followed by group div
}
else {
image.src = EXPAND;
group.className="collapsedgroup";
}
};
/* @method public imgToggle() - event handler for the img tags that contain the expand/collapse icons.
/* @param event - the event object
*/
function imgToggle(event)
{
var imgItem = getTarget(event);
if (!imgItem || imgItem.tagName.toLowerCase() != "img") {
alert(imgItem);
}
var treeItemDiv = imgItem.parentNode; // parent of expand/collapse img is div
var treeItem = getTreeItemFromPar(treeItemDiv);
var hasChildren = treeItem.getAttribute("aria-expanded") != null;
var isItemOpen = hasChildren && treeItem.getAttribute("aria-expanded") == 'true';
var tree= getTree(treeItem);
if (isItemOpen) {
// if closing: need to determine if current focus is on a treeitem within the hierarchy of this item - if so,
// need to update focus to this item.
// next sibling of expand/collapse item is group; check all children of group and its next siblings to see if any have focus
var searchStart = treeItemDiv.nextSibling;
while (searchStart && isText(searchStart) ) {
searchStart = searchStart.nextSibling;
}
var bFound = false;
bFound = isContainedChild(searchStart, tree.lastFocus);
if (bFound) {
treeItemFocus(treeItem,false); //update stored focus item; focus will actually be set with setFocus() call below
}
}
toggleExpandCollapse(treeItem, isItemOpen);
setFocus(tree.lastFocus);
}
/* @method public getTreeItemFromPar() - helper function to extract the inner span from the parent div.
* @param itemDiv - the div object that contains the actual treeitem span
* @return - the span object which is the treeitem.
*/
function getTreeItemFromPar(itemDiv)
{
var treeItem = null;
if (itemDiv && itemDiv.childNodes) {
for (var i=0; i<itemDiv.childNodes.length; i++) {
if (getRole(itemDiv.childNodes[i]) == ROLE_TREEITEM) {
treeItem = itemDiv.childNodes[i];
break;
}
}
}
return treeItem;
};
/* @method public isContainedChild() - see if the item is found as any child within a parent tree. This is called when the
* mouse is used to collapse an item. Must check to see if focus is currently in any children of the item being closed. This
* function recursively checks the childNodes of the parent item to see if the specifed item is found.
* @param parent - object where search for children begins
* @param item - treeItem object being search for within parent
* @returns - boolean true if item found, false if not.
*/
function isContainedChild(parent,item)
{
var bFound = false;
if (parent.hasChildNodes()) {
for (var i=0; i<parent.childNodes.length; i++) {
if (parent.childNodes[i] == item) {
bFound = true;
}
else {
bFound = isContainedChild(parent.childNodes[i],item);
}
if (bFound == true) {
break;
}
}
}
return bFound;
};