001/**
002 *   GRANITE DATA SERVICES
003 *   Copyright (C) 2006-2013 GRANITE DATA SERVICES S.A.S.
004 *
005 *   This file is part of the Granite Data Services Platform.
006 *
007 *   Granite Data Services is free software; you can redistribute it and/or
008 *   modify it under the terms of the GNU Lesser General Public
009 *   License as published by the Free Software Foundation; either
010 *   version 2.1 of the License, or (at your option) any later version.
011 *
012 *   Granite Data Services is distributed in the hope that it will be useful,
013 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
014 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser
015 *   General Public License for more details.
016 *
017 *   You should have received a copy of the GNU Lesser General Public
018 *   License along with this library; if not, write to the Free Software
019 *   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
020 *   USA, or see <http://www.gnu.org/licenses/>.
021 */
022package org.granite.spring.data;
023
024import java.io.IOException;
025import java.lang.reflect.Field;
026import java.lang.reflect.InvocationTargetException;
027import java.util.ArrayList;
028import java.util.Arrays;
029import java.util.List;
030
031import org.granite.messaging.jmf.ExtendedObjectInput;
032import org.granite.messaging.jmf.ExtendedObjectOutput;
033import org.granite.messaging.jmf.codec.ExtendedObjectCodec;
034import org.springframework.data.domain.Page;
035import org.springframework.data.domain.PageImpl;
036import org.springframework.data.domain.Pageable;
037import org.springframework.data.domain.Sort;
038import org.springframework.data.domain.Sort.Direction;
039import org.springframework.data.domain.Sort.Order;
040
041/**
042 * @author Franck WOLFF
043 */
044public class PageableCodec implements ExtendedObjectCodec {
045    
046        private static final Field pageableField;
047        static {
048                Field pageableFieldTmp = null;
049                try {
050                        pageableFieldTmp = PageImpl.class.getDeclaredField("pageable");
051                        pageableFieldTmp.setAccessible(true);
052                }
053                catch (NoSuchFieldException e) {
054                        // Other exception mean that Spring Data is not present
055                    // Don't catch so codec is not installed
056                }
057                pageableField = pageableFieldTmp;
058        }
059
060        public PageableCodec() {
061        }
062
063        public boolean canEncode(ExtendedObjectOutput out, Object v) {
064                return v instanceof Page;
065        }
066
067        public String getEncodedClassName(ExtendedObjectOutput out, Object v) {
068                return org.granite.tide.data.model.Page.class.getName();
069        }
070
071        public void encode(ExtendedObjectOutput out, Object v) throws IOException, IllegalAccessException, InvocationTargetException {
072                @SuppressWarnings("unchecked")
073                Page<Object> springPage = (Page<Object>)v;
074                
075                int offset;
076                if (springPage instanceof PageImpl && pageableField != null) {
077            Pageable springPageable = (Pageable)pageableField.get(springPage);
078            offset = springPageable.getOffset();
079        }
080                else
081                        offset = springPage.getNumber() * springPage.getSize();
082                
083                out.writeObject(Integer.valueOf(offset));
084                out.writeObject(Integer.valueOf(springPage.getSize()));
085                out.writeObject(Integer.valueOf((int)springPage.getTotalElements()));
086                out.writeObject(new ArrayList<Object>(springPage.getContent()));
087        }
088
089        public boolean canDecode(ExtendedObjectInput in, String className) throws ClassNotFoundException {
090                return org.granite.tide.data.model.PageInfo.class.getName().equals(className);
091        }
092
093        public String getDecodedClassName(ExtendedObjectInput in, String className) {
094                return OffsetPageRequest.class.getName();
095        }
096
097        public Object newInstance(ExtendedObjectInput in, String className)
098                        throws IOException, ClassNotFoundException, InstantiationException,
099                        IllegalAccessException, InvocationTargetException,
100                        SecurityException, NoSuchMethodException {
101                
102                int firstResult = ((Integer)in.readObject()).intValue();
103                int maxResults = ((Integer)in.readObject()).intValue();
104                String[] orderBys = (String[])in.readObject();
105                boolean[] orderDescs = (boolean[])in.readObject();
106                
107                Sort sort = null;
108                if (checkSort(orderBys, orderDescs)) {
109                        List<Order> orders = new ArrayList<Order>(orderBys.length);
110                        for (int i = 0; i < orderBys.length; i++)
111                                orders.add(new Order(orderDescs[i] ? Direction.DESC : Direction.ASC, orderBys[i]));
112                        sort = new Sort(orders);
113                }
114                
115                return new OffsetPageRequest(firstResult, maxResults, sort);
116        }
117
118        public void decode(ExtendedObjectInput in, Object v) throws IOException,
119                        ClassNotFoundException, IllegalAccessException,
120                        InvocationTargetException {
121        }
122        
123        private boolean checkSort(String[] orderBys, boolean[] orderDescs) {
124                if (orderBys != null) {
125                        if (orderDescs == null)
126                                throw new IllegalArgumentException("orderBys == " + Arrays.toString(orderBys) + " but sortDescs == null");
127                        if (orderDescs.length != orderBys.length)
128                                throw new IllegalArgumentException("orderBys == " + Arrays.toString(orderBys) + " but sortDescs == " + Arrays.toString(orderBys));
129                        return orderBys.length > 0;
130                }
131                else if (orderDescs != null)
132                        throw new IllegalArgumentException("orderBys == null but sortDescs != null");
133                return false;
134        }
135}