com.google.gwt.user.cellview.client.AbstractCellTree Maven / Gradle / Ivy
/*
* Copyright 2010 Google Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may not
* use this file except in compliance with the License. You may obtain a copy of
* the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations under
* the License.
*/
package com.google.gwt.user.cellview.client;
import com.google.gwt.event.logical.shared.CloseEvent;
import com.google.gwt.event.logical.shared.CloseHandler;
import com.google.gwt.event.logical.shared.HasCloseHandlers;
import com.google.gwt.event.logical.shared.HasOpenHandlers;
import com.google.gwt.event.logical.shared.OpenEvent;
import com.google.gwt.event.logical.shared.OpenHandler;
import com.google.gwt.event.shared.HandlerRegistration;
import com.google.gwt.user.client.ui.Composite;
import com.google.gwt.view.client.TreeViewModel;
import com.google.gwt.view.client.TreeViewModel.NodeInfo;
/**
* An abstract representation of a tree widget that renders items using
* {@link com.google.gwt.cell.client.Cell}s.
*/
public abstract class AbstractCellTree extends Composite implements
HasOpenHandlers, HasCloseHandlers,
HasKeyboardSelectionPolicy {
private KeyboardSelectionPolicy keyboardSelectionPolicy = KeyboardSelectionPolicy.ENABLED;
/**
* The {@link TreeViewModel} that backs the tree.
*/
private final TreeViewModel viewModel;
/**
* Construct a new {@link CellTree} with the specified {@link TreeViewModel}
* and root value.
*
* @param viewModel the {@link TreeViewModel} that backs the tree
*/
public AbstractCellTree(TreeViewModel viewModel) {
this.viewModel = viewModel;
}
public HandlerRegistration addCloseHandler(CloseHandler handler) {
return addHandler(handler, CloseEvent.getType());
}
public HandlerRegistration addOpenHandler(OpenHandler handler) {
return addHandler(handler, OpenEvent.getType());
}
public KeyboardSelectionPolicy getKeyboardSelectionPolicy() {
return keyboardSelectionPolicy;
}
/**
* Get the root {@link TreeNode}.
*
* @return the {@link TreeNode} at the root of the tree
*/
public abstract TreeNode getRootTreeNode();
/**
* Get the {@link TreeViewModel} that backs this tree.
*
* @return the {@link TreeViewModel}
*/
public TreeViewModel getTreeViewModel() {
return viewModel;
}
public void setKeyboardSelectionPolicy(KeyboardSelectionPolicy policy) {
if (policy == null) {
throw new NullPointerException("KeyboardSelectionPolicy cannot be null");
}
this.keyboardSelectionPolicy = policy;
}
/**
* Get the {@link NodeInfo} that will provide the information to retrieve and
* display the children of the specified value.
*
* @param value the value in the parent node
* @return the {@link NodeInfo}
*/
protected NodeInfo getNodeInfo(T value) {
return viewModel.getNodeInfo(value);
}
/**
* Check if keyboard selection is disabled.
*
* @return true if disabled, false if enabled.
*/
protected boolean isKeyboardSelectionDisabled() {
return KeyboardSelectionPolicy.DISABLED == keyboardSelectionPolicy;
}
/**
* Check if the value is known to be a leaf node.
*
* @param value the value at the node
*
* @return true if the node is known to be a leaf node, false otherwise
*/
protected boolean isLeaf(Object value) {
return viewModel.isLeaf(value);
}
}