Tree.java

/*
 * Copyright 2015 JBoss, by Red Hat, 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 org.uberfire.ext.widgets.core.client.tree;

import java.util.Iterator;

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.HasSelectionHandlers;
import com.google.gwt.event.logical.shared.OpenEvent;
import com.google.gwt.event.logical.shared.OpenHandler;
import com.google.gwt.event.logical.shared.SelectionEvent;
import com.google.gwt.event.logical.shared.SelectionHandler;
import com.google.gwt.event.shared.HandlerRegistration;
import com.google.gwt.user.client.ui.Composite;
import com.google.gwt.user.client.ui.FlowPanel;
import org.uberfire.ext.widgets.core.client.resources.TreeNavigatorResources;

public class Tree extends Composite implements HasSelectionHandlers<TreeItem>,
                                               HasOpenHandlers<TreeItem>,
                                               HasCloseHandlers<TreeItem> {

    final FlowPanel container = new FlowPanel();

    private TreeItem curSelection = null;

    public Tree() {
        initWidget(container);
        container.setStylePrimaryName(TreeNavigatorResources.INSTANCE.css().tree());
    }

    @Override
    public HandlerRegistration addOpenHandler(final OpenHandler<TreeItem> handler) {
        return addHandler(handler,
                          OpenEvent.getType());
    }

    @Override
    public HandlerRegistration addCloseHandler(final CloseHandler<TreeItem> handler) {
        return addHandler(handler,
                          CloseEvent.getType());
    }

    @Override
    public HandlerRegistration addSelectionHandler(final SelectionHandler<TreeItem> handler) {
        return addHandler(handler,
                          SelectionEvent.getType());
    }

    public void clear() {
        container.clear();
    }

    void fireStateChanged(final TreeItem item,
                          final TreeItem.State state) {
        if (state.equals(TreeItem.State.OPEN)) {
            OpenEvent.fire(this,
                           item);
        } else {
            CloseEvent.fire(this,
                            item);
        }
        onSelection(item,
                    true);
    }

    public void setSelectedItem(final TreeItem item,
                                final boolean fireEvents) {
        onSelection(item,
                    fireEvents);
    }

    public TreeItem getSelectedItem() {
        return curSelection;
    }

    public void setSelectedItem(final TreeItem item) {
        onSelection(item,
                    true);
    }

    void onSelection(final TreeItem item,
                     final boolean fireEvents) {
        if (curSelection != null) {
            curSelection.setSelected(false);
        }
        curSelection = item;

        if (curSelection != null) {
            // Select the item and fire the selection event.
            curSelection.setSelected(true);
            if (fireEvents) {
                SelectionEvent.fire(this,
                                    curSelection);
            }
        }
    }

    public TreeItem addItem(final TreeItem.Type type,
                            final String value) {
        final TreeItem item = new TreeItem(type,
                                           value);
        return addItem(item);
    }

    public TreeItem addItem(final TreeItem item) {
        container.add(item);
        item.setTree(this);
        return item;
    }

    public void removeItem(final TreeItem treeItem) {
        container.remove(treeItem);
    }

    public Iterable<TreeItem> getItems() {
        return new Iterable<TreeItem>() {
            @Override
            public Iterator<TreeItem> iterator() {
                return new TreeItem.TreeItemIterator(container);
            }
        };
    }

    public boolean isEmpty() {
        return container.getWidgetCount() == 0;
    }
}