org.apache.wicket.markup.html.link.BookmarkablePageLink.java Source code

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Here is the source code for org.apache.wicket.markup.html.link.BookmarkablePageLink.java

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/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.apache.wicket.markup.html.link;

import org.apache.wicket.Page;
import org.apache.wicket.request.mapper.parameter.PageParameters;
import org.apache.wicket.core.util.lang.WicketObjects;

/**
 * Renders a stable link which can be cached in a web browser and used at a later time.
 * 
 * @author Jonathan Locke
 * @param <T>
 *            type of model object, if any
 */
public class BookmarkablePageLink<T> extends Link<T> {
    private static final long serialVersionUID = 1L;

    /** The page class that this link links to. */
    private final String pageClassName;

    /** The parameters to pass to the class constructor when instantiated. */
    protected PageParameters parameters;

    /**
     * Constructor.
     * 
     * @param <C>
     *            type of page
     * 
     * @param id
     *            The name of this component
     * @param pageClass
     *            The class of page to link to
     */
    public <C extends Page> BookmarkablePageLink(final String id, final Class<C> pageClass) {
        this(id, pageClass, null);
    }

    /**
     * @return page parameters
     */
    public PageParameters getPageParameters() {
        if (parameters == null) {
            parameters = new PageParameters();
        }
        return parameters;
    }

    /**
     * Constructor.
     * 
     * @param <C>
     * 
     * @param id
     *            See Component
     * @param pageClass
     *            The class of page to link to
     * @param parameters
     *            The parameters to pass to the new page when the link is clicked
     */
    public <C extends Page> BookmarkablePageLink(final String id, final Class<C> pageClass,
            final PageParameters parameters) {
        super(id);

        this.parameters = parameters;

        if (pageClass == null) {
            throw new IllegalArgumentException("Page class for bookmarkable link cannot be null");
        } else if (!Page.class.isAssignableFrom(pageClass)) {
            throw new IllegalArgumentException("Page class must be derived from " + Page.class.getName());
        }
        pageClassName = pageClass.getName();
    }

    /**
     * Get the page class registered with the link
     * 
     * @return Page class
     */
    public final Class<? extends Page> getPageClass() {
        return WicketObjects.resolveClass(pageClassName);
    }

    /**
     * Whether this link refers to the given page.
     * 
     * @param page
     *            the page
     * @see org.apache.wicket.markup.html.link.Link#linksTo(org.apache.wicket.Page)
     */
    @Override
    public boolean linksTo(final Page page) {
        return page.getClass() == getPageClass();
    }

    @Override
    protected boolean getStatelessHint() {
        return true;
    }

    /**
     * THIS METHOD IS NOT USED! Bookmarkable links do not have a click handler. It is here to
     * satisfy the interface only, as bookmarkable links will be dispatched by the handling servlet.
     * 
     * @see org.apache.wicket.markup.html.link.Link#onClick()
     */
    @Override
    public final void onClick() {
        // Bookmarkable links do not have a click handler.
        // Instead they are dispatched by the request handling servlet.
    }

    /**
     * Gets the url to use for this link.
     * 
     * @return The URL that this link links to
     * @see org.apache.wicket.markup.html.link.Link#getURL()
     */
    @Override
    protected CharSequence getURL() {
        PageParameters parameters = getPageParameters();

        return urlFor(getPageClass(), parameters);
    }
}