name.martingeisse.admin.navigation.component.NavigationMenuPanel.java Source code

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Here is the source code for name.martingeisse.admin.navigation.component.NavigationMenuPanel.java

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/**
 * Copyright (c) 2011 Martin Geisse
 *
 * This file is distributed under the terms of the MIT license.
 */

package name.martingeisse.admin.navigation.component;

import java.util.List;

import name.martingeisse.admin.navigation.NavigationNode;
import name.martingeisse.admin.navigation.NavigationUtil;

import org.apache.commons.lang3.StringUtils;
import org.apache.wicket.behavior.AttributeAppender;
import org.apache.wicket.markup.html.basic.Label;
import org.apache.wicket.markup.html.link.AbstractLink;
import org.apache.wicket.markup.html.list.ListItem;
import org.apache.wicket.markup.html.list.ListView;
import org.apache.wicket.markup.html.panel.Panel;
import org.apache.wicket.model.IModel;
import org.apache.wicket.model.PropertyModel;

/**
 * This component uses a list model of element type {@link NavigationNode}
 * and shows links for all nodes. It has its own markup that is repeated
 * at each nesting level. 
 * 
 * This class has a maximum nesting depth that determines how many node
 * sub-levels are shown. Each sub-level of each node is recursively handled
 * by an instance of this class. Since the markup from this class is
 * repeated at each nesting level, the supported depth is infinite in
 * principle, and the default value for the maximum nesting depth is
 * in fact infinite (actually, {@link Integer#MAX_VALUE}.
 * 
 * Subclass markup: No combined markup inheritance via wicket:extend
 * is supported (i.e. the markup for this component does not contain a
 * wicket:child), but subclasses may override the whole markup.
 */
public final class NavigationMenuPanel extends Panel {

    /**
     * the maximumNestingDepth
     */
    private final int maximumNestingDepth;

    /**
     * the currentPagePath
     */
    private transient String currentPagePath;

    /**
     * Constructor.
     * @param id the wicket id
     */
    public NavigationMenuPanel(final String id) {
        this(id, Integer.MAX_VALUE);
    }

    /**
     * Constructor.
     * @param id the wicket id
     * @param maximumNestingDepth the maximum nesting depth
     */
    public NavigationMenuPanel(final String id, final int maximumNestingDepth) {
        super(id);
        this.maximumNestingDepth = maximumNestingDepth;
    }

    /**
     * Constructor.
     * @param id the wicket id
     * @param model the model
     */
    public NavigationMenuPanel(final String id, final IModel<List<NavigationNode>> model) {
        this(id, model, Integer.MAX_VALUE);
    }

    /**
     * Constructor.
     * @param id the wicket id
     * @param model the model
     * @param maximumNestingDepth the maximum nesting depth
     */
    public NavigationMenuPanel(final String id, final IModel<List<NavigationNode>> model,
            final int maximumNestingDepth) {
        super(id, model);
        this.maximumNestingDepth = maximumNestingDepth;
    }

    /**
     * Returns the model for the node list.
     * @return the model
     */
    @SuppressWarnings("unchecked")
    public IModel<List<NavigationNode>> getModel() {
        return (IModel<List<NavigationNode>>) getDefaultModel();
    }

    /* (non-Javadoc)
     * @see org.apache.wicket.Component#onInitialize()
     */
    @Override
    protected void onInitialize() {
        super.onInitialize();
        add(new ListView<NavigationNode>("nodes", getModel()) {
            @Override
            protected void populateItem(final ListItem<NavigationNode> item) {
                NavigationMenuPanel.this.populateItem(item);
            }
        });
    }

    /* (non-Javadoc)
     * @see org.apache.wicket.markup.repeater.AbstractRepeater#onBeforeRender()
     */
    @Override
    protected void onBeforeRender() {
        currentPagePath = StringUtils.defaultString(NavigationUtil.getNavigationPathForPage(getPage()));
        super.onBeforeRender();
    }

    /**
     * This method is used to populate the node items.
     * @param item the item to populate
     */
    protected void populateItem(final ListItem<NavigationNode> item) {

        // create the node link
        final NavigationNode node = item.getModelObject();
        final AbstractLink link = node.createLink("link");
        link.add(new Label("title", node.getTitle()));
        item.add(link);

        // mark or disable the link based on the current location
        final String nodePath = node.getPath();
        if (nodePath.equals(currentPagePath)) {
            link.setEnabled(false);
        } else if (node.isEqualOrPlausibleAncestorOf(currentPagePath)) {
            link.add(new AttributeAppender("style", "color: red"));
        }

        // create a panel for the children, but hide if the maximum nesting level is reached
        final IModel<List<NavigationNode>> childrenModel = new PropertyModel<List<NavigationNode>>(item.getModel(),
                "children");
        final NavigationMenuPanel childrenPanel = new NavigationMenuPanel("children", childrenModel,
                maximumNestingDepth - 1);
        item.add(childrenPanel);
        if (maximumNestingDepth == 0) {
            childrenPanel.setVisible(false);
        }

    }

}