wickettree.Node.java Source code

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Here is the source code for wickettree.Node.java

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/*
 * Copyright 2009 Sven Meier
 *
 * 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 wickettree;

import org.apache.wicket.Component;
import org.apache.wicket.MarkupContainer;
import org.apache.wicket.ajax.AjaxRequestTarget;
import org.apache.wicket.ajax.markup.html.AjaxFallbackLink;
import org.apache.wicket.behavior.Behavior;
import org.apache.wicket.markup.ComponentTag;
import org.apache.wicket.markup.html.panel.Panel;
import org.apache.wicket.model.IModel;

import wickettree.AbstractTree.State;

/**
 * Representation of a single node in the tree. By default uses an
 * {@link AjaxFallbackLink} for its junction component.
 * 
 * @see #createJunctionComponent(String)
 * 
 * @author Sven Meier
 */
public abstract class Node<T> extends Panel {

    private static final long serialVersionUID = 1L;

    public static final String CONTENT_ID = "content";

    private AbstractTree<T> tree;

    public Node(String id, AbstractTree<T> tree, IModel<T> model) {
        super(id, model);

        this.tree = tree;

        setOutputMarkupId(true);

        MarkupContainer junction = createJunctionComponent("junction");
        junction.add(new StyleBehavior());
        add(junction);

        Component content = createContent(CONTENT_ID, model);
        if (!content.getId().equals(CONTENT_ID)) {
            throw new IllegalArgumentException("content must have component id equal to Node.CONTENT_ID");
        }
        add(content);
    }

    @SuppressWarnings("unchecked")
    public IModel<T> getModel() {
        return (IModel<T>) getDefaultModel();
    }

    public T getModelObject() {
        return getModel().getObject();
    }

    /**
     * The junction component expands and collapses this node.
     */
    protected MarkupContainer createJunctionComponent(String id) {
        return new AjaxFallbackLink<Void>(id) {
            private static final long serialVersionUID = 1L;

            @Override
            public void onClick(AjaxRequestTarget target) {
                toggle();
            }

            @Override
            public boolean isEnabled() {
                return tree.getProvider().hasChildren(Node.this.getModelObject());
            }
        };
    }

    private void toggle() {
        T t = getModelObject();

        if (tree.getState(t) == State.EXPANDED) {
            tree.collapse(t);
        } else {
            tree.expand(t);
        }
    }

    /**
     * Create the component to display the actual node's content.
     * 
     * @param id
     *            the component id
     * @param model
     *            the node's model
     */
    protected abstract Component createContent(String id, IModel<T> model);

    /**
     * Get the style class depending on the current {@link State} of this node.
     * 
     * @see #getExpandedStyleClass(Object)
     * @see #getCollapsedStyleClass()
     * @see #getOtherStyleClass()
     */
    protected String getStyleClass() {
        T t = getModelObject();

        if (tree.getProvider().hasChildren(t)) {
            if (tree.getState(t) == State.EXPANDED) {
                return getExpandedStyleClass(t);
            } else {
                return getCollapsedStyleClass();
            }
        }
        return getOtherStyleClass();
    }

    protected String getExpandedStyleClass(T t) {
        return "tree-junction-expanded";
    }

    protected String getCollapsedStyleClass() {
        return "tree-junction-collapsed";
    }

    protected String getOtherStyleClass() {
        return "tree-junction";
    }

    /**
     * Behavior to add the style class attribute.
     * 
     * @see Node#getStyleClass()
     */
    private static class StyleBehavior extends Behavior {
        private static final long serialVersionUID = 1L;

        @Override
        public void onComponentTag(Component component, ComponentTag tag) {
            Node<?> node = (Node<?>) component.getParent();

            String styleClass = node.getStyleClass();
            if (styleClass != null) {
                tag.put("class", styleClass);
            }
        }
    }
}