001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017package org.apache.wicket.markup.html.navigation.paging;
018
019import org.apache.wicket.Page;
020import org.apache.wicket.markup.html.link.DisabledAttributeLinkBehavior;
021import org.apache.wicket.markup.html.link.Link;
022
023/**
024 * A link to a page of a PageableListView.
025 * 
026 * @author Jonathan Locke
027 * @author Eelco Hillenius
028 * @author Martijn Dashorst
029 * @param <T>
030 *            type of model object
031 */
032public class PagingNavigationLink<T> extends Link<T>
033{
034        private static final long serialVersionUID = 1L;
035
036        /** The pageable list view. */
037        protected final IPageable pageable;
038
039        /** The page of the PageableListView this link is for. */
040        private final long pageNumber;
041
042        /**
043         * Constructor.
044         * 
045         * @param id
046         *            See Component
047         * @param pageable
048         *            The pageable component for this page link
049         * @param pageNumber
050         *            The page number in the PageableListView that this link links to. Negative
051         *            pageNumbers are relative to the end of the list.
052         */
053        public PagingNavigationLink(final String id, final IPageable pageable, final long pageNumber)
054        {
055                super(id);
056                setAutoEnable(true);
057                this.pageNumber = pageNumber;
058                this.pageable = pageable;
059                
060                add(new DisabledAttributeLinkBehavior());
061        }
062
063        /**
064         * @see org.apache.wicket.markup.html.link.Link#onClick()
065         */
066        @Override
067        public void onClick()
068        {
069                pageable.setCurrentPage(getPageNumber());
070        }
071
072        /**
073         * Get pageNumber.
074         * 
075         * @return pageNumber.
076         */
077        public final long getPageNumber()
078        {
079                return cullPageNumber(pageNumber);
080        }
081
082        /**
083         * Allows the link to cull the page number to the valid range before it is retrieved from the
084         * link
085         * 
086         * @param pageNumber
087         * @return culled page number
088         */
089        protected long cullPageNumber(long pageNumber)
090        {
091                long idx = pageNumber;
092                if (idx < 0)
093                {
094                        idx = pageable.getPageCount() + idx;
095                }
096
097                if (idx > (pageable.getPageCount() - 1))
098                {
099                        idx = pageable.getPageCount() - 1;
100                }
101
102                if (idx < 0)
103                {
104                        idx = 0;
105                }
106
107                return idx;
108        }
109
110        /**
111         * @return True if this page is the first page of the containing PageableListView
112         */
113        public final boolean isFirst()
114        {
115                return getPageNumber() == 0;
116        }
117
118        /**
119         * @return True if this page is the last page of the containing PageableListView
120         */
121        public final boolean isLast()
122        {
123                return getPageNumber() == (pageable.getPageCount() - 1);
124        }
125
126        /**
127         * Returns true if this PageableListView navigation link links to the given page.
128         * 
129         * @param page
130         *            The page
131         * @return True if this link links to the given page
132         * @see org.apache.wicket.markup.html.link.Link#linksTo(org.apache.wicket.Page)
133         */
134        @Override
135        public final boolean linksTo(final Page page)
136        {
137                return getPageNumber() == pageable.getCurrentPage();
138        }
139}