opendaylight/northbound/networkconfiguration/neutron/src/main/java/org/opendaylight/controller/networkconfig/neutron/northbound/PaginatedRequestFactory.java

   1 /*
   2  * Copyright (C) 2014 Red Hat, Inc.
   3  *
   4  * This program and the accompanying materials are made available under the
   5  * terms of the Eclipse Public License v1.0 which accompanies this distribution,
   6  * and is available at http://www.eclipse.org/legal/epl-v10.html
   7  *
   8  *  Authors : Dave Tucker
   9  */
  10
  11 package org.opendaylight.controller.networkconfig.neutron.northbound;
  12
  13 import java.util.ArrayList;
  14 import java.util.Collections;
  15 import java.util.Comparator;
  16 import java.util.List;
  17 import javax.ws.rs.core.UriInfo;
  18 import org.opendaylight.controller.networkconfig.neutron.INeutronObject;
  19 import org.opendaylight.controller.networkconfig.neutron.NeutronNetwork;
  20 import org.opendaylight.controller.networkconfig.neutron.NeutronPort;
  21 import org.opendaylight.controller.networkconfig.neutron.NeutronSubnet;
  22 import org.opendaylight.controller.northbound.commons.exception.BadRequestException;
  23 import org.opendaylight.controller.northbound.commons.exception.ResourceNotFoundException;
  24
  25 public class PaginatedRequestFactory {
  26
  27     public static class PaginationResults<T extends INeutronObject> {
  28         List<T> collection;
  29         List<NeutronPageLink> links;
  30
  31         public PaginationResults(List<T> collection, List<NeutronPageLink> links) {
  32             this.collection = collection;
  33             this.links = links;
  34         }
  35     }
  36
  37     /*
  38      * SuppressWarnings is needed because the compiler does not understand that we
  39      * are actually safe here.
  40      *
  41      * FIXME: the only caller performs a cast back, so this is not actually necessary.
  42      */
  43     @SuppressWarnings("unchecked")
  44     public static <T extends INeutronObject> INeutronRequest<T> createRequest(Integer limit, String marker,
  45                                                                            Boolean pageReverse,
  46                                                                            UriInfo uriInfo,
  47                                                                            List<T> collection,
  48                                                                            Class<T> clazz) {
  49         PaginationResults<T> results = _paginate(limit, marker, pageReverse, uriInfo, collection);
  50
  51         if (clazz.equals(NeutronNetwork.class)){
  52             return (INeutronRequest<T>) new NeutronNetworkRequest((List<NeutronNetwork>) results.collection, results.links);
  53         }
  54         if (clazz.equals(NeutronSubnet.class)){
  55             return (INeutronRequest<T>) new NeutronSubnetRequest((List<NeutronSubnet>) results.collection, results.links);
  56         }
  57         if (clazz.equals(NeutronPort.class)){
  58             return (INeutronRequest<T>) new NeutronPortRequest((List<NeutronPort>) results.collection, results.links);
  59         }
  60         return null;
  61     }
  62
  63     private static <T extends INeutronObject> PaginationResults<T> _paginate(Integer limit, String marker, Boolean pageReverse, UriInfo uriInfo, List<T> collection) {
  64         List<NeutronPageLink> links = new ArrayList<>();
  65         Integer startPos = null;
  66         String startMarker;
  67         String endMarker;
  68         Boolean firstPage = false;
  69         Boolean lastPage = false;
  70
  71         Comparator<INeutronObject> neutronObjectComparator = new Comparator<INeutronObject>() {
  72             @Override
  73             public int compare(INeutronObject o1, INeutronObject o2) {
  74                 return o1.getID().compareTo(o2.getID());
  75             }
  76         };
  77
  78         Collections.sort(collection, neutronObjectComparator);
  79
  80         if (marker == null) {
  81             startPos = 0;
  82         }
  83
  84         else {
  85
  86             class MarkerObject implements INeutronObject {
  87                 private String id;
  88
  89                 @Override
  90                 public String getID() {
  91                     return id;
  92                 }
  93
  94                 @Override
  95                 public void setID(String id) {
  96                     this.id = id;
  97                 }
  98             }
  99
 100             INeutronObject markerObject = new MarkerObject();
 101
 102             markerObject.setID(marker);
 103
 104             startPos = Collections.binarySearch(collection, markerObject, neutronObjectComparator);
 105
 106             if (!pageReverse){
 107                 startPos = startPos + 1;
 108             }
 109             else {
 110                 startPos = startPos - limit;
 111             }
 112
 113         }
 114
 115         if (startPos == null) {
 116             throw new ResourceNotFoundException("UUID for marker:" + marker + " could not be found");
 117         }
 118
 119         if (startPos == 0){
 120             firstPage = true;
 121         }
 122
 123         if (startPos + limit >= collection.size()) {
 124             collection = collection.subList(startPos, collection.size());
 125             startMarker = collection.get(0).getID();
 126             endMarker = collection.get(collection.size() - 1).getID();
 127             lastPage = true;
 128         }
 129         else if (startPos < 0) {
 130             if (startPos + limit > 0) {
 131                 collection = collection.subList(0, startPos + limit);
 132                 startMarker = collection.get(0).getID();
 133                 endMarker = collection.get(collection.size() - 1).getID();
 134                 firstPage = true;
 135             }
 136             else {
 137                 throw new BadRequestException("Requested page is out of bounds. Please check the supplied limit and marker");
 138             }
 139         }
 140         else {
 141             collection = collection.subList(startPos, startPos + limit);
 142             startMarker = collection.get(0).getID();
 143             endMarker = collection.get(limit-1).getID();
 144         }
 145
 146         if (!lastPage) {
 147             NeutronPageLink next = new NeutronPageLink();
 148             next.setRef("next");
 149             next.setHref(uriInfo.getAbsolutePath().toString() + "?limit=" + limit.toString() + "&marker=" + endMarker);
 150             links.add(next);
 151         }
 152
 153         if (!firstPage) {
 154             NeutronPageLink previous = new NeutronPageLink();
 155             previous.setRef("previous");
 156             previous.setHref(uriInfo.getAbsolutePath().toString() + "?limit=" + limit.toString() + "&marker=" + startMarker + "&page_reverse=True");
 157             links.add(previous);
 158         }
 159
 160         return new PaginationResults<T>(collection, links);
 161     }
 162 }