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 org.opendaylight.controller.networkconfig.neutron.INeutronObject;
  14 import org.opendaylight.controller.networkconfig.neutron.NeutronNetwork;
  15 import org.opendaylight.controller.networkconfig.neutron.NeutronPort;
  16 import org.opendaylight.controller.networkconfig.neutron.NeutronSubnet;
  17 import org.opendaylight.controller.northbound.commons.exception.BadRequestException;
  18 import org.opendaylight.controller.northbound.commons.exception.ResourceNotFoundException;
  19
  20 import javax.ws.rs.core.UriInfo;
  21 import java.util.ArrayList;
  22 import java.util.Collections;
  23 import java.util.Comparator;
  24 import java.util.List;
  25
  26 public class PaginatedRequestFactory {
  27
  28     public static class PaginationResults<T extends INeutronObject> {
  29         List<T> collection;
  30         List<NeutronPageLink> links;
  31
  32         public PaginationResults(List<T> collection, List<NeutronPageLink> links) {
  33             this.collection = collection;
  34             this.links = links;
  35         }
  36     }
  37
  38     public static <T extends INeutronObject> INeutronRequest createRequest(Integer limit, String marker,
  39                                                                            Boolean pageReverse,
  40                                                                            UriInfo uriInfo,
  41                                                                            List<T> collection,
  42                                                                            Class<T> clazz) {
  43         PaginationResults results = _paginate(limit, marker, pageReverse, uriInfo, collection);
  44
  45         if (clazz.equals(NeutronNetwork.class)){
  46             return new NeutronNetworkRequest(results.collection, results.links);
  47         }
  48         if (clazz.equals(NeutronSubnet.class)){
  49             return new NeutronSubnetRequest(results.collection, results.links);
  50         }
  51         if (clazz.equals(NeutronPort.class)){
  52             return new NeutronPortRequest(results.collection, results.links);
  53         }
  54         return null;
  55     }
  56
  57     private static <T extends INeutronObject> PaginationResults _paginate(Integer limit, String marker, Boolean pageReverse, UriInfo uriInfo, List<T> collection) {
  58         List<NeutronPageLink> links = new ArrayList<>();
  59         Integer startPos = null;
  60         String startMarker;
  61         String endMarker;
  62         Boolean firstPage = false;
  63         Boolean lastPage = false;
  64
  65         Comparator<INeutronObject> neutronObjectComparator = new Comparator<INeutronObject>() {
  66             @Override
  67             public int compare(INeutronObject o1, INeutronObject o2) {
  68                 return o1.getID().compareTo(o2.getID());
  69             }
  70         };
  71
  72         Collections.sort(collection, neutronObjectComparator);
  73
  74         if (marker == null) {
  75             startPos = 0;
  76         }
  77
  78         else {
  79
  80             class MarkerObject implements INeutronObject {
  81                 private String id;
  82
  83                 public String getID() {
  84                     return id;
  85                 }
  86
  87                 public void setID(String id) {
  88                     this.id = id;
  89                 }
  90             }
  91
  92             INeutronObject markerObject = new MarkerObject();
  93
  94             markerObject.setID(marker);
  95
  96             startPos = Collections.binarySearch(collection, markerObject, neutronObjectComparator);
  97
  98             if (!pageReverse){
  99                 startPos = startPos + 1;
 100             }
 101             else {
 102                 startPos = startPos - limit;
 103             }
 104
 105         }
 106
 107         if (startPos == null) {
 108             throw new ResourceNotFoundException("UUID for marker:" + marker + " could not be found");
 109         }
 110
 111         if (startPos == 0){
 112             firstPage = true;
 113         }
 114
 115         if (startPos + limit >= collection.size()) {
 116             collection = collection.subList(startPos, collection.size());
 117             startMarker = collection.get(0).getID();
 118             endMarker = collection.get(collection.size() - 1).getID();
 119             lastPage = true;
 120         }
 121         else if (startPos < 0) {
 122             if (startPos + limit > 0) {
 123                 collection = collection.subList(0, startPos + limit);
 124                 startMarker = collection.get(0).getID();
 125                 endMarker = collection.get(collection.size() - 1).getID();
 126                 firstPage = true;
 127             }
 128             else {
 129                 throw new BadRequestException("Requested page is out of bounds. Please check the supplied limit and marker");
 130             }
 131         }
 132         else {
 133             collection = collection.subList(startPos, startPos + limit);
 134             startMarker = collection.get(0).getID();
 135             endMarker = collection.get(limit-1).getID();
 136         }
 137
 138         if (!lastPage) {
 139             NeutronPageLink next = new NeutronPageLink();
 140             next.setRef("next");
 141             next.setHref(uriInfo.getAbsolutePath().toString() + "?limit=" + limit.toString() + "&marker=" + endMarker);
 142             links.add(next);
 143         }
 144
 145         if (!firstPage) {
 146             NeutronPageLink previous = new NeutronPageLink();
 147             previous.setRef("previous");
 148             previous.setHref(uriInfo.getAbsolutePath().toString() + "?limit=" + limit.toString() + "&marker=" + startMarker + "&page_reverse=True");
 149             links.add(previous);
 150         }
 151
 152         return new PaginationResults(collection, links);
 153     }
 154 }