org.apache.wicket.markup.html.navigation.paging.PagingNavigationIncrementLink.java Source code

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Here is the source code for org.apache.wicket.markup.html.navigation.paging.PagingNavigationIncrementLink.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.navigation.paging;

import org.apache.wicket.Page;
import org.apache.wicket.markup.html.link.DisabledAttributeLinkBehavior;
import org.apache.wicket.markup.html.link.Link;

/**
 * An incremental link to a page of a PageableListView. Assuming your list view navigation looks
 * like
 * 
 * <pre>
 * 
 *       [first / &lt;&lt; / &lt;] 1 | 2 | 3 [&gt; / &gt;&gt; /last]
 * 
 * </pre>
 * 
 * <p>
 * and "&lt;" meaning the previous and "&lt;&lt;" goto the "current page - 5", than it is this kind
 * of incremental page links which can easily be created.
 * 
 * @author Juergen Donnerstag
 * @author Martijn Dashorst
 * @param <T>
 *            type of model object
 */
public class PagingNavigationIncrementLink<T> extends Link<T> {
    private static final long serialVersionUID = 1L;

    /** The increment. */
    private final int increment;

    /** The PageableListView the page links are referring to. */
    protected final IPageable pageable;

    /**
     * Constructor.
     * 
     * @param id
     *            See Component
     * @param pageable
     *            The pageable component the page links are referring to
     * @param increment
     *            increment by
     */
    public PagingNavigationIncrementLink(final String id, final IPageable pageable, final int increment) {
        super(id);
        setAutoEnable(true);
        this.increment = increment;
        this.pageable = pageable;

        add(new DisabledAttributeLinkBehavior());
    }

    /**
     * @see org.apache.wicket.markup.html.link.Link#onClick()
     */
    @Override
    public void onClick() {
        // Tell the PageableListView which page to print next
        pageable.setCurrentPage(getPageNumber());

        // Return the current page.
        setResponsePage(getPage());
    }

    /**
     * Determines the next page number for the pageable component.
     * 
     * @return the new page number
     */
    public final long getPageNumber() {
        // Determine the page number based on the current
        // PageableListView page and the increment
        long idx = pageable.getCurrentPage() + increment;

        // make sure the index lies between 0 and the last page
        return Math.max(0, Math.min(pageable.getPageCount() - 1, idx));
    }

    /**
     * @return True if it is referring to the first page of the underlying PageableListView.
     */
    public boolean isFirst() {
        return pageable.getCurrentPage() <= 0;
    }

    /**
     * @return True if it is referring to the last page of the underlying PageableListView.
     */
    public boolean isLast() {
        return pageable.getCurrentPage() >= (pageable.getPageCount() - 1);
    }

    /**
     * Returns true if the page link links to the given page.
     * 
     * @param page
     *            ignored
     * @return True if this link links to the given page
     * @see org.apache.wicket.markup.html.link.BookmarkablePageLink#linksTo(org.apache.wicket.Page)
     */
    @Override
    public boolean linksTo(final Page page) {
        pageable.getCurrentPage();
        return ((increment < 0) && isFirst()) || ((increment > 0) && isLast());
    }
}