@openui5/sap.ui.core/src/sap/ui/model/odata/ODataTreeBindingFlat.js

OpenUI5 Core Library sap.ui.core

/*!
 * OpenUI5
 * (c) Copyright 2026 SAP SE or an SAP affiliate company.
 * Licensed under the Apache License, Version 2.0 - see LICENSE.txt.
 */
/*eslint-disable max-len */
// Provides class sap.ui.model.odata.ODataTreeBindingFlat
sap.ui.define([
	"sap/base/assert",
	"sap/base/Log",
	"sap/base/util/extend",
	"sap/base/util/isEmptyObject",
	"sap/base/util/uid",
	"sap/ui/model/_Helper",
	"sap/ui/model/ChangeReason",
	"sap/ui/model/Context",
	"sap/ui/model/Filter",
	"sap/ui/model/TreeBinding",
	"sap/ui/model/TreeBindingUtils",
	"sap/ui/model/odata/v2/ODataTreeBinding"
], function(assert, Log, extend, isEmptyObject, uid, _Helper, ChangeReason, Context, Filter,
		TreeBinding, TreeBindingUtils, ODataTreeBinding) {
	"use strict";

	var sClassName = "sap.ui.model.odata.ODataTreeBindingFlat";

	/**
	 * Adapter for TreeBindings to add the ListBinding functionality and use the
	 * tree structure in list based controls.
	 *
	 * @alias sap.ui.model.odata.ODataTreeBindingFlat
	 * @function
	 *
	 * @public
	 */
	var ODataTreeBindingFlat = function() {

		// ensure only TreeBindings are enhanced which have not been enhanced yet
		if (!(this instanceof TreeBinding) || this._bIsAdapted) {
			return;
		}

		// apply the methods of the adapters prototype to the TreeBinding instance
		for (var fn in ODataTreeBindingFlat.prototype) {
			if (ODataTreeBindingFlat.prototype.hasOwnProperty(fn)) {
				this[fn] = ODataTreeBindingFlat.prototype[fn];
			}
		}

		// make sure we have a parameter object
		this.mParameters = this.mParameters || {};

		// keep track of the page-size for expand request
		this._iPageSize = 0;

		// flat data structure to store the tree nodes depth-first ordered
		this._aNodes = this._aNodes || [];

		// the node cache for the last requested nodes (via getContexts)
		this._aNodeCache = [];

		// the tree states
		this._aCollapsed = this._aCollapsed || [];
		this._aExpanded = this._aExpanded || [];
		this._aRemoved = [];
		this._aAdded = [];
		this._aNodeChanges = [];
		this._aAllChangedNodes = [];
		this._aTurnedToLeaf = [];

		// a map of all subtree handles, which are removed from the tree (and may be re-inserted)
		this._mSubtreeHandles = {};

		// lowest server-index level, will be kept correct when loading new entries
		this._iLowestServerLevel = null;

		// selection state
		this._aExpandedAfterSelectAll = this._aExpandedAfterSelectAll || [];
		this._mSelected = this._mSelected || {};
		this._mDeselected = this._mDeselected || {};
		this._bSelectAll = false;

		// the delta variable for calculating the correct binding-length (used e.g. for sizing the scrollbar)
		this._iLengthDelta = 0;

		//default value for collapse recursive
		if (this.mParameters.collapseRecursive === undefined) {
			this.bCollapseRecursive = true;
		} else {
			this.bCollapseRecursive = !!this.mParameters.collapseRecursive;
		}

		this._bIsAdapted = true;

		this._bReadOnly = true;

		this._aPendingRequests = [];
		this._aPendingChildrenRequests = [];
		this._aPendingSubtreeRequests = [];
		// TODO: No longer required in legacy-free UI5
		// Whether ODataTreeBindingFlat#submitChanges has been called
		this._bSubmitChangesCalled = false;
	};

	/**
	 * Sets the number of expanded levels.
	 *
	 * @param {number} iLevels The number of levels which should be expanded, minimum is 0
	 *
	 * @protected
	 * @see sap.ui.model.odata.v2.ODataTreeBinding#setNumberOfExpandedLevels
	 * @ui5-restricted sap.ui.table.AnalyticalTable
	 */
	ODataTreeBindingFlat.prototype.setNumberOfExpandedLevels = function(iLevels) {
		this.resetData();
		ODataTreeBinding.prototype.setNumberOfExpandedLevels.apply(this, arguments);
	};

	/**
	 * Gets an array of contexts for the requested part of the tree.
	 *
	 * @param {number} [iStartIndex=0]
	 *   The index of the first requested context
	 * @param {number} [iLength]
	 *   The maximum number of returned contexts; if not given the model's size limit is used; see
	 *   {@link sap.ui.model.Model#setSizeLimit}
	 * @param {number} [iThreshold=0]
	 *   The maximum number of contexts to read to read additionally as buffer
	 * @return {sap.ui.model.Context[]}
	 *   The requested tree contexts
	 *
	 * @protected
	 */
	ODataTreeBindingFlat.prototype.getContexts = function (iStartIndex, iLength, iThreshold) {
		return this._getContextsOrNodes(false, iStartIndex, iLength, iThreshold);
	};

	/**
	 * Gets an array of either node objects or contexts for the requested part of the tree.
	 *
	 * @param {boolean} bReturnNodes
	 *   Whether to return node objects or contexts
	 * @param {number} [iStartIndex=0]
	 *   The index of the first requested node or context
	 * @param {number} [iLength]
	 *   The maximum number of returned nodes or contexts; if not given the model's size limit is
	 *   used; see {@link sap.ui.model.Model#setSizeLimit}
	 * @param {number} [iThreshold=0]
	 *   The maximum number of nodes or contexts to read additionally as buffer
	 * @return {object[]|sap.ui.model.Context[]}
	 *   The requested tree nodes or contexts
	 *
	 * @private
	 */
	ODataTreeBindingFlat.prototype._getContextsOrNodes = function (bReturnNodes, iStartIndex,
			iLength, iThreshold) {
		if (!this.isResolved() || this.isInitial()) {
			return [];
		}

		iStartIndex = iStartIndex || 0;
		iLength = iLength || this.oModel.iSizeLimit;
		iThreshold = iThreshold || 0;

		this._iPageSize = iLength;
		this._iThreshold = iThreshold;

		// shortcut for initial load
		if (this._aNodes.length == 0 && !this.isLengthFinal()) {
			this._loadData(iStartIndex, iLength, iThreshold);
		}

		// cut out the requested section from the tree
		var aResultContexts = [];
		var aNodes = this._retrieveNodeSection(iStartIndex, iLength);

		// clear node cache
		this._aNodeCache = [];

		// calculate $skip and $top values
		var iSkip;
		var iTop = 0;
		var iLastServerIndex = 0;

		// potentially missing entries for each parent deeper than the # of expanded levels
		var mGaps = {};

		for (var i = 0; i < aNodes.length; i++) {
			var oNode = aNodes[i];

			// cache node for more efficient access on the currently visible nodes in the TreeTable
			// only cache nodes which are real contexts
			this._aNodeCache[iStartIndex + i] = oNode && oNode.context ? oNode : undefined;

			aResultContexts.push(oNode.context);

			if (!oNode.context) {
				if (oNode.serverIndex != undefined) { // 0 is a valid server-index!
					// construct the $skip to $top range for server indexed nodes
					if (iSkip == undefined) {
						iSkip = oNode.serverIndex;
					}
					iLastServerIndex = oNode.serverIndex;
				} else if (oNode.positionInParent != undefined) { //0 is a valid index here too
					// nodes, which don't have a context but a positionInParent property, are manually expanded missing nodes
					var oParent = oNode.parent;
					mGaps[oParent.key] = mGaps[oParent.key] || [];
					mGaps[oParent.key].push(oNode);
				}
			}
		}

		// $top needs to be at minimum 1
		iTop = 1 + Math.max(iLastServerIndex - (iSkip || 0), 0);

		//if something is missing on the server indexed nodes -> request it
		if (iSkip != undefined && iTop) {
			this._loadData(iSkip, iTop, iThreshold);
		}

		//check if we are missing some manually expanded nodes
		for (var sMissingKey in mGaps) {
			var oRequestParameters = this._calculateRequestParameters(mGaps[sMissingKey]);
			this._loadChildren(mGaps[sMissingKey][0].parent, oRequestParameters.skip, oRequestParameters.top);
		}

		// either return nodes or contexts
		if (bReturnNodes) {
			return aNodes;
		} else {
			return aResultContexts;
		}
	};

	/**
	 * Calculates the $skip and $top for the OData request.
	 *
	 * @param {object[]} aMissing An array of missing nodes
	 * @returns {object} An object with <code>skip</code> and <code>top</code>
	 *
	 * @private
	 */
	ODataTreeBindingFlat.prototype._calculateRequestParameters = function (aMissing) {
		var i,
			iMissingSkip = aMissing[0].positionInParent,
			oParent = aMissing[0].parent,
			iMissingLength = Math.min(iMissingSkip + Math.max(this._iThreshold, aMissing.length),
				oParent.children.length);

		for (i = iMissingSkip; i < iMissingLength; i++) {
			var oChild = oParent.children[i];
			if (oChild) {
				break;
			}
		}

		return {
			skip: iMissingSkip,
			top: i - iMissingSkip
		};
	};

	/**
	 * Cuts out a piece from the tree.
	 *
	 * @param {number} iStartIndex The first index to cut out
	 * @param {number} iLength The number of nodes to cut
	 *
	 * @returns {object[]} The cut nodes
	 *
	 * @private
	 */
	ODataTreeBindingFlat.prototype._retrieveNodeSection = function (iStartIndex, iLength) {
		return this._bReadOnly
			? this._indexRetrieveNodeSection(iStartIndex, iLength)
			: this._mapRetrieveNodeSection(iStartIndex, iLength);
	};

	/**
	 * Checks whether there is a pending request to get the children for the given node key.
	 *
	 * @param {string} sNodeKey The node key
	 *
	 * @returns {boolean} Whether there is a pending request fetching the children of the given node
	 *
	 * @private
	 */
	ODataTreeBindingFlat.prototype._hasPendingRequest = function (sNodeKey) {
		return this._aPendingChildrenRequests.some((oRequest) => oRequest.sParent === sNodeKey);
	};

	/**
	 * Turn the given node to a leaf
	 *
	 * @param {object} oNode The node
	 *
	 * @private
	 */
	ODataTreeBindingFlat.prototype._turnNodeToLeaf = function (oNode) {
		oNode.nodeState.collapsed = false;
		oNode.nodeState.expanded = false;
		oNode.nodeState.isLeaf = true;
		oNode.nodeState.wasExpanded = true;
		this._aTurnedToLeaf.push(oNode);
	};

	/*
	 * @private
	 */
	ODataTreeBindingFlat.prototype._mapRetrieveNodeSection = function (iStartIndex, iLength) {
		const iLastNodeIndex = this.getLength() - 1;
		var iNodeCounter = -1;
		var aNodes = [];
		let oPreviousNode;

		this._map((oNode, oRecursionBreaker, sIndexType, iIndex, oParent) => {
			iNodeCounter++;
			if (oNode && this._aRemoved.length) {
				// check if previous node has to be a leaf node
				if (oPreviousNode && oPreviousNode.nodeState.expanded
						&& oPreviousNode.level >= oNode.level
						&& !this._hasPendingRequest(oPreviousNode.key)) {
					this._turnNodeToLeaf(oPreviousNode);
				} else if (oNode.nodeState.expanded && iLastNodeIndex === iNodeCounter
					&& !this._hasPendingRequest(oNode.key)) {
					// Leaf transformation process for the last element in the tree
					this._turnNodeToLeaf(oNode);
				}
			}
			oPreviousNode = oNode;

			if (iNodeCounter >= iStartIndex) {
				// if we have a missing node and it is a server-indexed node -> introduce a gap object
				if (!oNode) {
					if (sIndexType == "serverIndex") {
						oNode = {
							serverIndex: iIndex
						};
					} else if (sIndexType == "positionInParent") {
						oNode = {
							positionInParent: iIndex,
							parent: oParent
						};
					}
				}
				aNodes.push(oNode);
			}
			if (aNodes.length >= iLength) {
				oRecursionBreaker.broken = true;
			}
		});
		return aNodes;
	};

	/*
	 * @private
	 */
	ODataTreeBindingFlat.prototype._indexRetrieveNodeSection = function (iStartIndex, iLength) {
		var i, aNodes =  [], oNodeInfo, oNode;

		for (i = iStartIndex; i < iStartIndex + iLength; i++) {
			oNodeInfo = this.getNodeInfoByRowIndex(i);
			if (oNodeInfo.index !== undefined && oNodeInfo.index < this._aNodes.length) {
				oNode = this._aNodes[oNodeInfo.index];
				if (!oNode) {
					oNode = {
						serverIndex: oNodeInfo.index
					};
				}
			} else if (oNodeInfo.parent) {
				oNode = oNodeInfo.parent.children[oNodeInfo.childIndex];
				if (!oNode) {
					oNode = {
						parent: oNodeInfo.parent,
						positionInParent: oNodeInfo.childIndex
					};
				}
			}

			if (oNode) {
				aNodes.push(oNode);
				oNode = null;
			}
		}
		return aNodes;
	};

	/**
	 * Gets an array of nodes for the requested part of the tree.
	 *
	 * @param {number} [iStartIndex=0]
	 *   The index of the first requested node
	 * @param {number} [iLength]
	 *   The maximum number of returned nodes; if not given the model's size limit is used; see
	 *   {@link sap.ui.model.Model#setSizeLimit}
	 * @param {number} [iThreshold=0]
	 *   The maximum number of nodes to read additionally as buffer
	 * @return {Object[]}
	 *   The requested tree nodes
	 *
	 * @protected
	 * @ui5-restricted sap.ui.table.TreeTable
	 */
	ODataTreeBindingFlat.prototype.getNodes = function (iStartIndex, iLength, iThreshold) {
		return this._getContextsOrNodes(true, iStartIndex, iLength, iThreshold);
	};



	/**
	 * Applies the given callback function to all tree nodes including server-index nodes and deep
	 * nodes. It iterates all tree nodes unless the property <code>broken</code> of the callback
	 * function parameter <code>oRecursionBreaker</code> is set to <code>true</code>.
	 *
	 * @param {function} fnMap
	 *   This callback function is called for all nodes of this tree. It has no return value and
	 *   gets the following parameters:
	 *   <ul>
	 *     <li>{object} oNode: The current tree node</li>
	 *     <li>{object} oRecursionBreaker: An object reference that allows to interrupt calling the
	 *       callback function with further tree nodes</li>
	 *     <li>{object} oRecursionBreaker.broken=false: Whether the recursion has to be interrupted
	 *       when the current <code>oNode</code> has finished processing</li>
	 *     <li>{string} sIndexType: Describes the node type ("serverIndex" for nodes on the highest
	 *       hierarchy, "positionInParent" for nodes in subtrees and "newNode" for newly added
	 *       nodes)</li>
	 *     <li>{int} [iIndex]: The structured position in the tree accessible with the property
	 *       described in <code>sIndexType</code></li>
	 *     <li>{object} [oParent]: The parent node of the current tree node</li>
	 *   </ul>
	 *
	 * @private
	 */
	ODataTreeBindingFlat.prototype._map = function (fnMap) {
		var fnCheckNodeForAddedSubtrees, fnTraverseAddedSubtree, fnTraverseDeepSubtree,
			fnTraverseFlatSubtree,
			oRecursionBreaker = {broken: false};

		/**
		 * Helper function to iterate all added subtrees of a node.
		 *
		 * @param {object} oNode The node to check for subtrees
		 */
		fnCheckNodeForAddedSubtrees = function (oNode) {
			// if there are subnodes added to the current node -> traverse them first (added nodes are at the top, before any children)
			if (oNode.addedSubtrees.length > 0 && !oNode.nodeState.collapsed) {
				// an added subtree can be either a deep or a flat tree (depending on the addContexts) call
				for (var j = 0; j < oNode.addedSubtrees.length; j++) {
					var oSubtreeHandle = oNode.addedSubtrees[j];
					fnTraverseAddedSubtree(oNode, oSubtreeHandle);
					if (oRecursionBreaker.broken) {
						return;
					}
				}
			}
		};

		/**
		 * Traverses a re-inserted or newly added subtree.
		 * This can be a combination of flat and deep trees.
		 *
		 * Decides if the traversal has to branche over to a flat or a deep part of the tree.
		 *
		 * @param {object} oNode
		 *   The parent node
		 * @param {object} oSubtreeHandle
		 *   The subtree handle, inside there is either a deep or a flat tree stored
		 */
		fnTraverseAddedSubtree = function (oNode, oSubtreeHandle) {
			var oSubtree = oSubtreeHandle._getSubtree();

			if (oSubtreeHandle) {
				// subtree is flat
				if (Array.isArray(oSubtree)) {
					if (oSubtreeHandle._oSubtreeRoot) {
						// jump to a certain position in the flat structure and map the nodes
						fnTraverseFlatSubtree(oSubtree, oSubtreeHandle._oSubtreeRoot.serverIndex, oSubtreeHandle._oSubtreeRoot, oSubtreeHandle._oSubtreeRoot.originalLevel || 0, oNode.level + 1);
					} else {
						// newly added nodes
						fnTraverseFlatSubtree(oSubtree, null, null, 0, oNode.level + 1);
					}

				} else {
					// subtree is deep
					oSubtreeHandle._oSubtreeRoot.level = oNode.level + 1;
					fnTraverseDeepSubtree(oSubtreeHandle._oSubtreeRoot, false, oSubtreeHandle._oNewParentNode, -1, oSubtreeHandle._oSubtreeRoot);
				}
			}
		};

		/**
		 * Recursive Tree Traversal
		 * @param {object} oNode the current node
		 * @param {boolean} bIgnore a flag to indicate if the node should be mapped
		 * @param {object} oParent the parent node of oNode
		 * @param {int} iPositionInParent the position of oNode in the children-array of oParent
		 * @param {object} [oIgnoreRemoveForNode] Newly inserted node which shouldn't be ignored
		 */
		fnTraverseDeepSubtree
				= function (oNode, bIgnore, oParent, iPositionInParent, oIgnoreRemoveForNode) {
			// ignore node if it was already mapped or is removed (except if it was reinserted, denoted by oIgnoreRemoveForNode)
			if (!bIgnore) {
				if (!oNode.nodeState.removed || oIgnoreRemoveForNode == oNode) {
					fnMap(oNode, oRecursionBreaker, "positionInParent", iPositionInParent, oParent);
					if (oRecursionBreaker.broken) {
						return;
					}
				}
			}
			fnCheckNodeForAddedSubtrees(oNode);
			if (oRecursionBreaker.broken) {
				return;
			}

			// if the node also has children AND is expanded, dig deeper
			if (oNode && oNode.children && oNode.nodeState.expanded) {
				for (var i = 0; i < oNode.children.length; i++) {
					var oChildNode = oNode.children[i];
					// Make sure that the level of all child nodes are adapted to the parent level,
					// this is necessary if the parent node was placed in a different leveled subtree.
					// Ignore removed nodes, which are not re-inserted.
					// Re-inserted deep nodes will be regarded in fnTraverseAddedSubtree.
					if (oChildNode && !oChildNode.nodeState.removed && !oChildNode.nodeState.reinserted) {
						oChildNode.level = oNode.level + 1;
					}
					// only dive deeper if we have a gap (entry which has to be loaded) or a defined node is NOT removed
					if (oChildNode && !oChildNode.nodeState.removed) {
						fnTraverseDeepSubtree(oChildNode, false, oNode, i, oIgnoreRemoveForNode);
					} else if (!oChildNode) {
						fnMap(oChildNode, oRecursionBreaker, "positionInParent", i, oNode);
					}
					if (oRecursionBreaker.broken) {
						return;
					}
				}
			}
		};

		/**
		 * Traverses a flat portion of the tree (or rather the given array).
		 *
		 * @param {object[]} aFlatTree
		 *   The flat tree to traverse
		 * @param {number} iServerIndexOffset
		 *   The server-index position, used to calculate $skip/$top
		 * @param {object} oIgnoreRemoveForNode
		 *   Newly inserted node which shouldn't be ignored
		 * @param {number} iSubtreeBaseLevel
		 *   Base level of the subtree
		 * @param {number} iNewParentBaseLevel
		 *   Base level of the new parent
		 */
		fnTraverseFlatSubtree
				= function (aFlatTree, iServerIndexOffset, oIgnoreRemoveForNode, iSubtreeBaseLevel,
					iNewParentBaseLevel) {
			//count the nodes until we find the correct index
			for (var i = 0; i < aFlatTree.length; i++) {
				var oNode = aFlatTree[i];

				// If the node is removed -> ignore it
				// BEWARE:
				// If a removed range is reinserted again, we will deliver it instead of jumping over it.
				// This is denoted by the "oIgnoreRemoveForNode", this is a node which will be served but only if it was traversed by fnTraverseAddedSubtree
				if (oNode && oNode.nodeState && oNode.nodeState.removed && oNode != oIgnoreRemoveForNode) {
					// only jump over the magnitude range if the node was not initially collapsed/server-expanded
					if (!oNode.initiallyCollapsed) {
						i += oNode.magnitude;
					}
					continue;
				}

				// calculate level shift if necessary (added subtrees are differently indented than before removal)
				if (oNode && iSubtreeBaseLevel >= 0 && iNewParentBaseLevel >= 0) {
					oNode.level = oNode.originalLevel || 0;
					var iLevelDifNormalized = (oNode.level - iSubtreeBaseLevel) || 0;
					oNode.level = iNewParentBaseLevel + iLevelDifNormalized || 0;
				}

				if (iServerIndexOffset === null) {
					fnMap(oNode, oRecursionBreaker, "newNode");
				} else {
					// call map for the node itself, before traversing to any children/siblings
					// the server-index position is used to calculate the $skip/$top values for loading the missing entries
					fnMap(oNode, oRecursionBreaker, "serverIndex", iServerIndexOffset + i);
				}

				if (oRecursionBreaker.broken) {
					return;
				}

				// if we have a node, lets see if we have to dig deeper or jump over some entries
				if (oNode && oNode.nodeState) {
					// jump over collapsed nodes by the enclosing magnitude
					if (!oNode.initiallyCollapsed && oNode.nodeState.collapsed) {
						i += oNode.magnitude;
					} else if (oNode.initiallyCollapsed && oNode.nodeState.expanded) {
						// look into expanded nodes deeper than the initial expand level
						// the node itself will be ignored, since its fnMap was already called
						fnTraverseDeepSubtree(oNode, true);
						if (oRecursionBreaker.broken) {
							return;
						}
					} else if (!oNode.initiallyCollapsed && oNode.nodeState.expanded) {
						// before going to the next flat node (children|sibling), we look at the added subtrees in between
						// this is only necessary for expanded server-indexed nodes
						fnCheckNodeForAddedSubtrees(oNode);
					}
				}

				// break recursion after fnMap or traversal function calls
				if (oRecursionBreaker.broken) {
					return;
				}
			}
		};

		//kickstart the traversal from the original flat nodes array (no server-index offset -> 0)
		fnTraverseFlatSubtree(this._aNodes, 0, null);
	};

	/**
	 * Loads the server-index nodes within the range [iSkip, iSkip + iTop + iThreshold) and merges the nodes into
	 * the inner structure.
	 *
	 * @param {int} iSkip The start index of the loading
	 * @param {int} iTop The number of nodes to be loaded
	 * @param {int} iThreshold The size of the buffer
	 * @return {Promise<Object>} The promise resolves if the reload finishes successfully, otherwise it's rejected. The promise
	 * 						resolves with an object which has the calculated iSkip, iTop and the loaded content under
	 * 						property oData. It rejects with the error object which is returned from the server.
	 *
	 * @private
	 */
	ODataTreeBindingFlat.prototype._loadData = function (iSkip, iTop, iThreshold) {
		var that = this;

		if (!this.bSkipDataEvents) {
			this.fireDataRequested();
		}
		this.bSkipDataEvents = false;

		return this._requestServerIndexNodes(iSkip, iTop, iThreshold).then(function(oResponseData) {
			that._addServerIndexNodes(oResponseData.oData, oResponseData.iSkip);

			that._fireChange({reason: ChangeReason.Change});
			that.fireDataReceived({data: oResponseData.oData});
		}, function(oError) {
			var bAborted = oError.statusCode === 0;
			if (!bAborted) {
				// reset data and trigger update
				that._aNodes = [];
				that._bLengthFinal = true;
				that._fireChange({reason: ChangeReason.Change});
				that.fireDataReceived();
			}
		});
	};

	/**
	 * Reloads the server-index nodes within the range [iSkip, iSkip + iTop) and merges them into the inner structure.
	 *
	 * @param {int} iSkip The start index of the loading
	 * @param {int} iTop The number of nodes to be loaded
	 * @param {boolean} bInlineCount Whether the inline count for all pages is requested
	 * @return {Promise<Object>} The promise resolves if the reload finishes successfully, otherwise it's rejected. The promise
	 * 						resolves with an object which has the calculated iSkip, iTop and the loaded content under
	 * 						property oData. It rejects with the error object which is returned from the server.
	 *
	 * @private
	 */
	ODataTreeBindingFlat.prototype._restoreServerIndexNodes = function (iSkip, iTop, bInlineCount) {
		var that = this;
		return this._requestServerIndexNodes(iSkip, iTop, 0, bInlineCount).then(function(oResponseData) {
			that._addServerIndexNodes(oResponseData.oData, oResponseData.iSkip);
			return oResponseData;
		});
	};

	/**
	 * Merges the nodes in parameter oData into the inner structure
	 *
	 * @param {object} oData The content which contains the nodes from the backend
	 * @param {int} iSkip The start index for the merging into inner structure
	 *
	 * @private
	 */
	ODataTreeBindingFlat.prototype._addServerIndexNodes = function (oData, iSkip) {
		var oEntry, sKey, iIndex, i,
			// the function is used to test whether one of its ascendant is expanded after the selectAll
			fnTest = function(oNode, index) {
				return (!oNode.isDeepOne && !oNode.initiallyCollapsed
					&& oNode.serverIndex < iIndex && oNode.serverIndex + oNode.magnitude >= iIndex);
			};


		// $inlinecount is in oData.__count, the $count is just oData
		if (!this._bLengthFinal) {
			var iCount = oData.__count ? parseInt(oData.__count) : 0;
			this._aNodes[iCount - 1] = undefined;
			this._bLengthFinal = true;
		}

		//merge data into flat array structure
		if (oData.results && oData.results.length > 0) {
			for (i = 0; i < oData.results.length; i++) {

				oEntry = oData.results[i];
				sKey = this.oModel.getKey(oEntry);
				iIndex = iSkip + i;

				const vMagnitude = oEntry[this.oTreeProperties["hierarchy-node-descendant-count-for"]];
				let iMagnitude = Number(vMagnitude);

				// check the magnitude attribute whether it's greater or equal than 0
				if (iMagnitude < 0) {
					iMagnitude = 0;
					Log.error("The entry data with key '" + sKey + "' under binding path '" + this.getPath() + "' has a negative 'hierarchy-node-descendant-count-for' which isn't allowed.");
				}
				if (!Number.isSafeInteger(iMagnitude)) {
					Log.error("The value of magnitude is not a safe integer: " + JSON.stringify(vMagnitude),
						this.getResolvedPath(), sClassName);
				}

				var oNode = this._aNodes[iIndex] = this._aNodes[iIndex] || {
					key: sKey,
					context: this.oModel.getContext("/" + sKey,
						this.oModel.resolveDeep(this.sPath, this.oContext) + sKey.slice(sKey.indexOf("("))),
					magnitude: iMagnitude,
					level: oEntry[this.oTreeProperties["hierarchy-level-for"]],
					originalLevel: oEntry[this.oTreeProperties["hierarchy-level-for"]],
					initiallyCollapsed: oEntry[this.oTreeProperties["hierarchy-drill-state-for"]] === "collapsed",
					initiallyIsLeaf : oEntry[this.oTreeProperties["hierarchy-drill-state-for"]] === "leaf",
					nodeState: {
						isLeaf: oEntry[this.oTreeProperties["hierarchy-drill-state-for"]] === "leaf",
						expanded: oEntry[this.oTreeProperties["hierarchy-drill-state-for"]] === "expanded",
						collapsed: oEntry[this.oTreeProperties["hierarchy-drill-state-for"]] === "collapsed",
						selected: this._mSelected[sKey] ? this._mSelected[sKey].nodeState.selected : false
					},
					children: [],
					// an array containing all added subtrees, may be new context nodes or nodes which were removed previously
					addedSubtrees: [],
					serverIndex: iIndex,
					// a server indexed node is not attributed with a parent, in contrast to the manually expanded nodes
					parent: null,
					originalParent : null,
					isDeepOne: false
				};

				// track the lowest server-index level --> used to find out if a node is on the top level
				if (this._iLowestServerLevel === null) {
					this._iLowestServerLevel = oNode.level;
				} else {
					this._iLowestServerLevel = Math.min(this._iLowestServerLevel, oNode.level);
				}

				// selection update if we are in select-all mode
				if (this._bSelectAll) {
					if (!this._aExpandedAfterSelectAll.some(fnTest)) {
						this.setNodeSelection(oNode, true);
					}
				}
			}
		}
	};

	/**
	 * Loads the server-index nodes based on the given range and the initial expand level.
	 *
	 * @param {int} iSkip The start index of the loading
	 * @param {int} iTop The number of nodes to be loaded
	 * @param {int} iThreshold The size of the buffer
	 * @param {boolean} bInlineCount Whether the inline count for all pages is requested
	 * @return {Promise<Object>} The promise resolves if the reload finishes successfully, otherwise it's rejected. The promise
	 * 						resolves with an object which has the calculated iSkip, iTop and the loaded content under
	 * 						property oData. It rejects with the error object which is returned from the server.
	 *
	 * @private
	 */
	ODataTreeBindingFlat.prototype._requestServerIndexNodes = function (iSkip, iTop, iThreshold, bInlineCount) {
		return new Promise(function(resolve, reject) {
			var oRequest = {
				iSkip: iSkip,
				iTop: iTop + (iThreshold || 0), // Top also contains threshold if applicable
				iThreshold: iThreshold
				// oRequestHandle: <will be set later>
			};

			// Order pending requests by index
			this._aPendingRequests.sort(function(a, b) {
				return a.iSkip - b.iSkip;
			});

			// Check pending requests:
			// - adjust new request if pending requests already cover parts of it (delta determination)
			// - ignore(/abort) new request if pending requests already cover it in full
			// - cancel pending requests if the new request covers them in full plus additional data.
			// handles will be aborted on filter/sort calls.
			for (var i = 0; i < this._aPendingRequests.length; i++) {
				if (TreeBindingUtils._determineRequestDelta(oRequest, this._aPendingRequests[i]) === false) {
					return; // ignore this request
				}
			}

			// Convenience
			iSkip = oRequest.iSkip;
			iTop = oRequest.iTop;

			function _handleSuccess (oData) {
				// Remove request from array
				var idx = this._aPendingRequests.indexOf(oRequest);
				this._aPendingRequests.splice(idx, 1);

				resolve({
					oData: oData,
					iSkip: iSkip,
					iTop: iTop
				});
			}

			function _handleError (oError) {
				// Remove request from array
				var idx = this._aPendingRequests.indexOf(oRequest);
				this._aPendingRequests.splice(idx, 1);

				reject(oError);
			}

			var aUrlParameters = ["$skip=" + iSkip, "$top=" + iTop];

			// request inlinecount only once
			if (!this._bLengthFinal || bInlineCount) {
				aUrlParameters.push("$inlinecount=allpages");
			}

			// add custom parameters (including $selects)
			if (this.sCustomParams) {
				aUrlParameters.push(this.sCustomParams);
			}

			// construct multi-filter for level filter and application filters
			var oLevelFilter = new Filter(this.oTreeProperties["hierarchy-level-for"], "LE", this.getNumberOfExpandedLevels());
			var aFilters = [oLevelFilter];
			this._checkFilterForTreeProperties();
			const oCombinedFilter = this.getCombinedFilter();
			if (oCombinedFilter) {
				aFilters.push(oCombinedFilter);
			}

			var sAbsolutePath = this.getResolvedPath();
			if (sAbsolutePath) {
				oRequest.oRequestHandle = this.oModel.read(sAbsolutePath, {
					headers: this._getHeaders(),
					urlParameters: aUrlParameters,
					filters: [new Filter({
						filters: aFilters,
						and: true
					})],
					sorters: this.aSorters || [],
					success: _handleSuccess.bind(this),
					error: _handleError.bind(this),
					groupId: this.sRefreshGroupId ? this.sRefreshGroupId : this.sGroupId
				});

				this._aPendingRequests.push(oRequest);
			}
		}.bind(this));
	};

	/*
	 * @private
	 */
	ODataTreeBindingFlat.prototype._propagateMagnitudeChange = function(oParent, iDelta) {
		// propagate the magnitude along the parent chain, up to the top parent which is a
		// server indexed node (checked by oParent.parent == null)
		// first magnitude starting point is the no. of direct children/the childCount
		while (oParent != null && (oParent.initiallyCollapsed || oParent.isDeepOne)) {
			oParent.magnitude += iDelta;
			if (!oParent.nodeState.expanded) {
				return;
			}

			//up one level, ends at parent == null
			oParent = oParent.parent;
		}
	};

	/*
	 * Calculates the magnitude of a server index node after the initial loading
	 *
	 * @private
	 */
	ODataTreeBindingFlat.prototype._getInitialMagnitude = function(oNode) {
		var iDelta = 0,
			oChild;

		if (oNode.isDeepOne) { // Use original value (not "new")
			return 0;
		}

		if (oNode.children) {
			for (var i = 0; i < oNode.children.length; i++) {
				oChild = oNode.children[i];
				iDelta += oChild.magnitude + 1;
			}
		}

		return oNode.magnitude - iDelta;
	};

	/**
	 * Loads the direct children of the <code>oParentNode</code> within the range [iSkip, iSkip + iTop) and merge the
	 * new nodes into the <code>children</code> array under the parent node.
	 *
	 * @param {object} oParentNode The parent node under which the children are loaded
	 * @param {int} iSkip The start index of the loading
	 * @param {int} iTop The number of nodes which will be loaded
	 *
	 * @private
	 */
	ODataTreeBindingFlat.prototype._loadChildren = function(oParentNode, iSkip, iTop) {
		var that = this;

		if (!this.bSkipDataEvents) {
			this.fireDataRequested();
		}
		this.bSkipDataEvents = false;

		this._requestChildren(oParentNode, iSkip, iTop).then(function(oResponseData) {
			that._addChildNodes(oResponseData.oData, oParentNode, oResponseData.iSkip);

			that._fireChange({reason: ChangeReason.Change});
			that.fireDataReceived({data: oResponseData.oData});
		}, function(oError) {
			var bAborted = oError.statusCode === 0;
			if (!bAborted) {
				// reset data and trigger update
				if (oParentNode.childCount === undefined) {
					oParentNode.children = [];
					oParentNode.childCount = 0;
					that._fireChange({reason: ChangeReason.Change});
				}
				that.fireDataReceived();
			}
		});
	};

	/**
	 * Reloads the child nodes of the <code>oParentNode</code> within the range [iSkip, iSkip + iTop) and merges them into the inner structure.
	 *
	 * After the child nodes are loaded, the parent node is expanded again.
	 *
	 * @param {object} oParentNode The parent node under which the children are reloaded
	 * @param {int} iSkip The start index of the loading
	 * @param {int} iTop The number of nodes to be loaded
	 * @return {Promise<Object>} The promise resolves if the reload finishes successfully, otherwise it's rejected. The promise
	 * 						resolves with an object which has the calculated iSkip, iTop and the loaded content under
	 * 						property oData. It rejects with the error object which is returned from the server.
	 *
	 * @private
	 */
	ODataTreeBindingFlat.prototype._restoreChildren = function(oParentNode, iSkip, iTop) {
		var that = this,
			// get the updated key from the context in case of insert
			sParentId = oParentNode.context.getProperty(this.oTreeProperties["hierarchy-node-for"]);
			// sParentKey = this.oModel.getKey(oParentNode.context);

		return this._requestChildren(oParentNode, iSkip, iTop, true/*request inline count*/).then(function(oResponseData) {
			var oNewParentNode;

			that._map(function(oNode, oRecursionBreaker) {
				if (oNode && oNode.context.getProperty(that.oTreeProperties["hierarchy-node-for"]) === sParentId) {
					oNewParentNode = oNode;
					oRecursionBreaker.broken = true;
				}
			});

			if (oNewParentNode) {
				that._addChildNodes(oResponseData.oData, oNewParentNode, oResponseData.iSkip);
				that.expand(oNewParentNode, true);
			}

			return oResponseData;
		});
	};

	/**
	 * Merges the nodes in <code>oData</code> into the <code>children</code> property under <code>oParentNode</code>.
	 *
	 * @param {object} oData The content which contains the nodes from the backed
	 * @param {object} oParentNode The parent node where the child nodes are saved
	 * @param {int} iSkip The start index for the merging into inner structure
	 *
	 * @private
	 */
	ODataTreeBindingFlat.prototype._addChildNodes = function(oData, oParentNode, iSkip) {

		// $inlinecount is in oData.__count
		// $count is just the 'oData' argument
		if (oParentNode.childCount == undefined && oData && oData.__count) {
			var iCount = oData.__count ? parseInt(oData.__count) : 0;
			oParentNode.childCount = iCount;
			oParentNode.children[iCount - 1] = undefined;

			if (oParentNode.nodeState.expanded) {
				// propagate the magnitude along the parent chain
				this._propagateMagnitudeChange(oParentNode, iCount);
			} else {
				// If parent node is not expanded, do not propagate magnitude change up to its parents
				oParentNode.magnitude = iCount;
			}

			// once when we reload data and know the direct-child count,
			// we have to keep track of the expanded state for the newly loaded nodes, so the length delta can be calculated
			this._cleanTreeStateMaps();
		}

		//merge data into flat array structure
		if (oData.results && oData.results.length > 0) {
			for (var i = 0; i < oData.results.length; i++) {

				var oEntry = oData.results[i];
				this._createChildNode(oEntry, oParentNode, iSkip + i);
			}
		}
	};

	/*
	 * @private
	 */
	ODataTreeBindingFlat.prototype._createChildNode = function(oEntry, oParentNode, iPositionInParent) {
		var sKey = this.oModel.getKey(oEntry);

		var iContainingServerIndex;
		if (oParentNode.containingServerIndex !== undefined) {
			iContainingServerIndex = oParentNode.containingServerIndex;
		} else {
			iContainingServerIndex = oParentNode.serverIndex;
		}
		var oNode = oParentNode.children[iPositionInParent] = oParentNode.children[iPositionInParent] || {
			key: sKey,
			context: this.oModel.getContext("/" + sKey,
				this.oModel.resolveDeep(this.sPath, this.oContext) + sKey.slice(sKey.indexOf("("))),
			//sub-child nodes have a magnitude of 0 at their first loading time
			magnitude: 0,
			//level is either given by the back-end or simply 1 level deeper than the parent
			level: oParentNode.level + 1,
			originalLevel: oParentNode.level + 1,
			initiallyCollapsed: oEntry[this.oTreeProperties["hierarchy-drill-state-for"]] === "collapsed",
			initiallyIsLeaf : oEntry[this.oTreeProperties["hierarchy-drill-state-for"]] === "leaf",
			//node state is also given by the back-end
			nodeState: {
				isLeaf: oEntry[this.oTreeProperties["hierarchy-drill-state-for"]] === "leaf",
				expanded: oEntry[this.oTreeProperties["hierarchy-drill-state-for"]] === "expanded",
				collapsed: oEntry[this.oTreeProperties["hierarchy-drill-state-for"]] === "collapsed",
				selected: this._mSelected[sKey] ? this._mSelected[sKey].nodeState.selected : false
			},
			positionInParent: iPositionInParent,
			children: [],
			// an array containing all added subtrees, may be new context nodes or nodes which were removed previously
			addedSubtrees: [],
			// a reference on the parent node, will only be set for manually expanded nodes, server-indexed node have a parent of null
			parent: oParentNode,
			// a reference on the original parent node, this property should not be changed by any algorithms, its used later to construct correct delete requests
			originalParent: oParentNode,
			// marks a node as a manually expanded one
			isDeepOne: true,
			// the deep child nodes have the same containing server index as the parent node
			// the parent node is either a server-index node or another deep node which already has a containing-server-index
			containingServerIndex: iContainingServerIndex
		};

		if (this._bSelectAll && this._aExpandedAfterSelectAll.indexOf(oParentNode) === -1) {
			this.setNodeSelection(oNode, true);
		}
		return oNode;
	};

	/**
	 * Loads the child nodes based on the given range and <code>oParentNode</code>
	 *
	 * @param {object} oParentNode The node under which the children are loaded
	 * @param {int} iSkip The start index of the loading
	 * @param {int} iTop The number of nodes to be loaded
	 * @param {boolean} bInlineCount Whether the inline count should be requested from the backend
	 * @return {Promise<Object>} The promise resolves if the reload finishes successfully, otherwise it's rejected. The promise
	 * 						resolves with an object which has the calculated iSkip, iTop and the loaded content under
	 * 						property oData. It rejects with the error object which is returned from the server.
	 *
	 * @private
	 */
	ODataTreeBindingFlat.prototype._requestChildren = function (oParentNode, iSkip, iTop, bInlineCount) {
		return new Promise(function(resolve, reject) {
			var oRequest = {
				sParent: oParentNode.key,
				iSkip: iSkip,
				iTop: iTop
				// oRequestHandle: <will be set later>
			};

			// Order pending requests by index
			this._aPendingChildrenRequests.sort(function(a, b) {
				return a.iSkip - b.iSkip;
			});

			// Check pending requests:
			// - adjust new request and remove parts that are already covered by pending requests
			// - ignore (abort) a new request if it is already covered by pending requests
			// - cancel pending requests if it is covered by the new request and additional data is added
			// handles will be aborted on filter/sort calls
			for (var i = 0; i < this._aPendingChildrenRequests.length; i++) {
				var oPendingRequest = this._aPendingChildrenRequests[i];
				if (oPendingRequest.sParent === oRequest.sParent) { // Parent key must match
					if (TreeBindingUtils._determineRequestDelta(oRequest, oPendingRequest) === false) {
						return; // ignore this request
					}
				}
			}

			// Convenience
			iSkip = oRequest.iSkip;
			iTop = oRequest.iTop;

			function _handleSuccess (oData) {

				// Remove request from array
				var idx = this._aPendingChildrenRequests.indexOf(oRequest);
				this._aPendingChildrenRequests.splice(idx, 1);

				resolve({
					oData: oData,
					iSkip: iSkip,
					iTop: iTop
				});
			}

			function _handleError (oError) {
				// Remove request from array
				var idx = this._aPendingChildrenRequests.indexOf(oRequest);
				this._aPendingChildrenRequests.splice(idx, 1);

				reject(oError);
			}

			var aUrlParameters = ["$skip=" + iSkip, "$top=" + iTop];

			// request inlinecount only once or inline count is needed explicitly
			if (oParentNode.childCount == undefined || bInlineCount) {
				aUrlParameters.push("$inlinecount=allpages");
			}

			// add custom parameters (including $selects)
			if (this.sCustomParams) {
				aUrlParameters.push(this.sCustomParams);
			}

			// construct multi-filter for level filter and application filters
			var oLevelFilter = new Filter(this.oTreeProperties["hierarchy-parent-node-for"], "EQ", oParentNode.context.getProperty(this.oTreeProperties["hierarchy-node-for"]));
			var aFilters = [oLevelFilter];
			if (this.aApplicationFilters) {
				aFilters = aFilters.concat(this.aApplicationFilters);
			}

			var sAbsolutePath = this.getResolvedPath();
			if (sAbsolutePath) {
				oRequest.oRequestHandle = this.oModel.read(sAbsolutePath, {
					headers: this._getHeaders(),
					urlParameters: aUrlParameters,
					filters: [new Filter({
						filters: aFilters,
						and: true
					})],
					sorters: this.aSorters || [],
					success: _handleSuccess.bind(this),
					error: _handleError.bind(this),
					groupId: this.sRefreshGroupId ? this.sRefreshGroupId : this.sGroupId
				});

				this._aPendingChildrenRequests.push(oRequest);
			}
		}.bind(this));
	};

	/**
	 * Loads the complete subtree of a given node up to a given level
	 *
	 * @param {object} oParentNode The root node of the requested subtree
	 * @param {int} iLevel The maximum expansion level of the subtree
	 * @return {Promise<Object>} Promise that resolves with the response data, parent key and level.
	 				It rejects with the error object which is returned from the server.
	 *
	 * @private
	 */
	ODataTreeBindingFlat.prototype._loadSubTree = function (oParentNode, iLevel) {
		var that = this;
		var missingSectionsLoaded;


		if (oParentNode.serverIndex !== undefined && !oParentNode.initiallyCollapsed) {
			//returns the nodes flat starting from the parent to the last one inside the magnitude range
			var aMissingSections = [];
			var oSection;
			var iSubTreeStart = oParentNode.serverIndex + 1;
			var iSubTreeEnd = iSubTreeStart + oParentNode.magnitude;
			for (var i = iSubTreeStart; i < iSubTreeEnd; i++) {
				if (this._aNodes[i] === undefined) {
					if (!oSection) {
						oSection = {
							iSkip: i,
							iTop: 1
						};
						aMissingSections.push(oSection);
					} else {
						oSection.iTop++;
					}
				} else {
					oSection = null;
				}
			}

			if (aMissingSections.length) {
				missingSectionsLoaded = Promise.all(aMissingSections.map(function (oMissingSection) {
					return that._loadData(oMissingSection.iSkip, oMissingSection.iTop);
				}));
			}
		}

		if (!missingSectionsLoaded) {
			missingSectionsLoaded = Promise.resolve();
		}

		return missingSectionsLoaded.then(function () {
			if (!that.bSkipDataEvents) {
				that.fireDataRequested();
			}
			that.bSkipDataEvents = false;
			return that._requestSubTree(oParentNode, iLevel).then(function(oResponseData) {
				that._addSubTree(oResponseData.oData, oParentNode);
				that.fireDataReceived({data: oResponseData.oData});
			}, function(oError) {
				Log.warning("ODataTreeBindingFlat: Error during subtree request", oError.message);

				var bAborted = oError.statusCode === 0;
				if (!bAborted) {
					that.fireDataReceived();
				}
			});
		});
	};

	/**
	 * Merges the subtree in <code>oData</code> into the inner structure and expands it
	 *
	 * @param {object} oData The content which contains the nodes from the backed
	 * @param {object} oSubTreeRootNode The root node of the subtree
	 *
	 * @private
	 */
	ODataTreeBindingFlat.prototype._addSubTree = function(oData, oSubTreeRootNode) {
		if (oData.results && oData.results.length > 0) {
			var sNodeId, sParentNodeId, oEntry, oNode, oParentNode,
				aAlreadyLoadedNodes = [],
				mParentNodes = {},
				i, j, k;

			if (oSubTreeRootNode.serverIndex !== undefined && !oSubTreeRootNode.initiallyCollapsed) {
				aAlreadyLoadedNodes = this._aNodes.slice(oSubTreeRootNode.serverIndex, oSubTreeRootNode.serverIndex + oSubTreeRootNode.magnitude + 1);
			} else {
				aAlreadyLoadedNodes.push(oSubTreeRootNode);
			}

			for (j = aAlreadyLoadedNodes.length - 1; j >= 0; j--) {
				oNode = aAlreadyLoadedNodes[j];
				if (oNode.nodeState.isLeaf) {
					continue; // Skip leaf nodes - they can't be parents
				}
				if (oNode.initiallyCollapsed || oNode.isDeepOne) {
					oNode.childCount = undefined; // We know all the children
					// Changes to a collapsed nodes magnitude must not be propagated
					if (oNode.magnitude && oNode.nodeState.expanded) {
						// Propagate negative magnitude change before resetting nodes magnitude
						this._propagateMagnitudeChange(oNode.parent, -oNode.magnitude);
					}
					oNode.magnitude = 0;
				}
				mParentNodes[oNode.context.getProperty(this.oTreeProperties["hierarchy-node-for"])] = oNode;
			}

			for (i = 0; i < oData.results.length; i++) {
				oEntry = oData.results[i];
				sNodeId = oEntry[this.oTreeProperties["hierarchy-node-for"]];

				if (mParentNodes[sNodeId]) {
					// Node already loaded as server index node
					continue;
				}

				sParentNodeId = oEntry[this.oTreeProperties["hierarchy-parent-node-for"]];
				oParentNode = mParentNodes[sParentNodeId];
				if (oParentNode.childCount === undefined) {
					oParentNode.childCount = 0;
				}

				oNode = oParentNode.children[oParentNode.childCount];
				if (oNode) {
					// Reuse existing nodes
					aAlreadyLoadedNodes.push(oNode);
					if (oNode.childCount) {
						oNode.childCount = undefined;
						if (oNode.initiallyCollapsed || oNode.isDeepOne) {
							oNode.magnitude = 0;
						}
					}
				} else {
					// Create new node
					oNode = this._createChildNode(oEntry, oParentNode, oParentNode.childCount);
					if (oNode.nodeState.expanded) {
						this._aExpanded.push(oNode);
						this._sortNodes(this._aExpanded);
					}
				}
				oParentNode.childCount++;
				if (oParentNode.nodeState.expanded) {
					// propagate the magnitude along the parent chain
					this._propagateMagnitudeChange(oParentNode, 1);
				} else {
					// If parent node is not expanded, do not propagate magnitude change up to its parents
					oParentNode.magnitude++;
				}
				if (!oNode.nodeState.isLeaf) {
					mParentNodes[sNodeId] = oNode;
				}
			}

			for (k = aAlreadyLoadedNodes.length - 1; k >= 0; k--) {
				oNode = aAlreadyLoadedNodes[k];
				if (!oNode.nodeState.expanded && !oNode.nodeState.isLeaf) {
					this.expand(oNode, true);
				}
			}
		}
	};

	/**
	 * Loads the complete subtree of a given node up to a given level
	 *
	 * @param {object} oParentNode The root node of the requested subtree
	 * @param {int} iLevel The maximum expansion level of the subtree
	 * @return {Promise<Object>} Promise that resolves with the response data, parent key and level.
	 				It rejects with the error object which is returned from the server.
	 *
	 * @private
	 */
	ODataTreeBindingFlat.prototype._requestSubTree = function (oParentNode, iLevel) {
		return new Promise(function(resolve, reject) {
			var oRequest = {
				sParent: oParentNode.key,
				iLevel: iLevel
				// oRequestHandle: <will be set later>
			};

			// Check pending requests:
			for (var i = 0; i < this._aPendingSubtreeRequests.length; i++) {
				var oPendingRequest = this._aPendingSubtreeRequests[i];
				if (oPendingRequest.sParent === oRequest.sParent && oPendingRequest.iLevel === oRequest.iLevel) {
					// Same request => ignore new request
					return;
				}
			}

			function _handleSuccess (oData) {
				// Remove request from array
				var idx = this._aPendingSubtreeRequests.indexOf(oRequest);
				this._aPendingSubtreeRequests.splice(idx, 1);

				resolve({
					oData: oData,
					sParent: oRequest.sParent,
					iLevel: oRequest.iLevel
				});
			}

			function _handleError (oError) {
				// Remove request from array
				var idx = this._aPendingSubtreeRequests.indexOf(oRequest);
				this._aPendingSubtreeRequests.splice(idx, 1);

				reject(oError);
			}

			var aUrlParameters = [];

			// add custom parameters (including $selects)
			if (this.sCustomParams) {
				aUrlParameters.push(this.sCustomParams);
			}

			// construct multi-filter for level filter and application filters
			const sHierarchyNodeForProperty = this.oTreeProperties["hierarchy-node-for"];
			const oNodeFilter = new Filter(sHierarchyNodeForProperty, "EQ",
					oParentNode.context.getProperty(sHierarchyNodeForProperty));
			var oLevelFilter = new Filter(this.oTreeProperties["hierarchy-level-for"], "LE", iLevel);
			var aFilters = [oNodeFilter, oLevelFilter];
			this._checkFilterForTreeProperties();
			const oCombinedFilter = this.getCombinedFilter();
			if (oCombinedFilter) {
				aFilters.push(oCombinedFilter);
			}

			var sAbsolutePath = this.getResolvedPath();
			if (sAbsolutePath) {
				oRequest.oRequestHandle = this.oModel.read(sAbsolutePath, {
					headers: this._getHeaders(),
					urlParameters: aUrlParameters,
					fil