NodeRenderer.java

/*******************************************************************************
 * Copyright (c) 2012-2017 Codenvy, S.A.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *   Codenvy, S.A. - initial API and implementation
 *******************************************************************************/
package org.eclipse.che.ide.ui.tree;

import elemental.dom.Element;
import elemental.html.SpanElement;

/**
 * Flyweight renderer whose job it is to take a NodeData and construct the
 * appropriate DOM structure for the tree node contents.
 *
 * @param <D>
 *         The type of data we want to render.
 */
public interface NodeRenderer<D> {

    /**
     * Takes in a {@link SpanElement} constructed via a call to
     * {@link #renderNodeContents} and returns an element whose contract is that
     * it contains only text corresponding to the key for the node's underlying
     * data.
     * <p/>
     * This ofcourse depends on the structure that was generated via the call to
     * {@link #renderNodeContents}.
     */
    Element getNodeKeyTextContainer(SpanElement treeNodeLabel);

    /**
     * Constructs the label portion of a {@link TreeNodeElement}. Labels can have
     * arbitrary DOM structure, with one constraint. At least one element MUST
     * contain only text that corresponds to the String key for the underlying
     * node's data.
     */
    SpanElement renderNodeContents(D data);

    /**
     * Updates the node's contents to reflect the current state of the node.
     *
     * @param treeNode
     *         the tree node that contains the rendered node contents
     */
    void updateNodeContents(TreeNodeElement<D> treeNode);
}