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Guise™ Internet application framework.
There is a newer version: 0.5.3
/*
 * Copyright © 2005-2008 GlobalMentor, 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 io.guise.framework.component;

import java.util.*;

import com.globalmentor.java.*;
import com.globalmentor.java.Objects;
import static com.globalmentor.java.Classes.*;
import com.globalmentor.net.*;

import io.guise.framework.*;
import io.guise.framework.component.layout.*;
import io.guise.framework.event.NavigateActionListener;

import static com.globalmentor.net.URIs.*;

/**
 * A panel displaying a navigation path as a series of breadcrumb links for the path segments. The navigation path is translated to depiction terms before being
 * displayed, so that the path segments are shown in depiction terms.
 * @author Garret Wilson
 * @see GuiseSession#getBreadcrumbs(URIPath)
 */
public class NavigationPathBreadcrumbLinkPanel extends AbstractPanel {

	/** The navigation path bound property. */
	public static final String NAVIGATION_PATH_PROPERTY = getPropertyName(NavigationPathBreadcrumbLinkPanel.class, "navigationPath");

	/** The navigation path, or null if there is no navigation path. */
	private URIPath navigationPath = null;

	/** @return The navigation path, or null if there is no navigation path. */
	public URIPath getNavigationPath() {
		return navigationPath;
	}

	/**
	 * Sets the navigation path. This is a bound property.
	 * @param newNavigationPath The new navigation path, or null if there should be no navigation navigation path.
	 * @see #NAVIGATION_PATH_PROPERTY
	 */
	public void setNavigationPath(final URIPath newNavigationPath) {
		if(!Objects.equals(navigationPath, newNavigationPath)) { //if the value is really changing
			final URIPath oldNavigationPath = navigationPath; //get the old value
			navigationPath = newNavigationPath; //actually change the value
			clear(); //clear all components from the container
			if(navigationPath != null) { //if there is a navigation path
				final GuiseSession session = getSession(); //get the Guise session
				final List breadcrumbs = session.getBreadcrumbs(navigationPath); //get the breadcrumbs for this navigation path
				final Iterator breadcrumbIterator = breadcrumbs.iterator(); //get an iterator to examine the breadcrumbs
				boolean hasNextBreadcrumb = breadcrumbIterator.hasNext(); //see if there is at least one breadcrumb
				while(hasNextBreadcrumb) { //while there are more breadcrumbs
					final Breadcrumb breadcrumb = breadcrumbIterator.next(); //get the next breadcrumb
					final Link link = new Link(breadcrumb); //create a link from the breadcrumb
					link.addActionListener(new NavigateActionListener(breadcrumb.getNavigationPath())); //add an action listener to navigate to the breadcrumb's navigation path
					add(link); //add the link for this breadcrumb
					hasNextBreadcrumb = breadcrumbIterator.hasNext(); //see if there is another breadcrumb
					if(hasNextBreadcrumb || navigationPath.isCollection()) { //if there is another breadcrumb or this breadcrumb is for a collection (i.e. if there should be a path separator at the end)
						final Label pathSeparaterLabel = new Label(); //create a new label for the path separator
						pathSeparaterLabel.setLabel(String.valueOf(PATH_SEPARATOR)); //set the label
						add(pathSeparaterLabel);
					}
				}
			}
			firePropertyChange(NAVIGATION_PATH_PROPERTY, oldNavigationPath, newNavigationPath); //indicate that the value changed
		}
	}

	/** Default constructor with a default horizontal flow layout. */
	public NavigationPathBreadcrumbLinkPanel() {
		this((URIPath)null); //default to no navigation path
	}

	/**
	 * Navigation path constructor with a default horizontal flow layout.
	 * @param navigationPath The navigation path, or null if there should be no navigation path.
	 */
	public NavigationPathBreadcrumbLinkPanel(final URIPath navigationPath) {
		this(new FlowLayout(Flow.LINE), navigationPath); //default to flowing horizontally
	}

	/**
	 * Layout constructor.
	 * @param layout The layout definition for the container.
	 * @throws NullPointerException if the given layout is null.
	 */
	public NavigationPathBreadcrumbLinkPanel(final Layout layout) {
		this(layout, null); //construct the class with no default label
	}

	/**
	 * Layout and URI constructor.
	 * @param layout The layout definition for the container.
	 * @param navigationPath The navigation path, or null if there should be no navigation path.
	 * @throws NullPointerException if the given layout is null.
	 */
	public NavigationPathBreadcrumbLinkPanel(final Layout layout, final URIPath navigationPath) {
		super(layout); //construct the parent class
		setNavigationPath(navigationPath); //set the path to that given
	}

}