git.opendaylight Code Review - controller.git/blob

   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     private static final Comparator<INeutronObject> NEUTRON_OBJECT_COMPARATOR = new Comparator<INeutronObject>() {
  27         @Override
  28         public int compare(INeutronObject o1, INeutronObject o2) {
  29             return o1.getID().compareTo(o2.getID());
  30         }
  31     };
  32
  33     public static class PaginationResults<T extends INeutronObject> {
  34         List<T> collection;
  35         List<NeutronPageLink> links;
  36
  37         public PaginationResults(List<T> collection, List<NeutronPageLink> links) {
  38             this.collection = collection;
  39             this.links = links;
  40         }
  41     }
  42
  43     /*
  44      * SuppressWarnings is needed because the compiler does not understand that we
  45      * are actually safe here.
  46      *
  47      * FIXME: the only caller performs a cast back, so this is not actually necessary.
  48      */
  49     @SuppressWarnings("unchecked")
  50     public static <T extends INeutronObject> INeutronRequest<T> createRequest(Integer limit, String marker,
  51                                                                            Boolean pageReverse,
  52                                                                            UriInfo uriInfo,
  53                                                                            List<T> collection,
  54                                                                            Class<T> clazz) {
  55         PaginationResults<T> results = _paginate(limit, marker, pageReverse, uriInfo, collection);
  56
  57         if (clazz.equals(NeutronNetwork.class)){
  58             return (INeutronRequest<T>) new NeutronNetworkRequest((List<NeutronNetwork>) results.collection, results.links);
  59         }
  60         if (clazz.equals(NeutronSubnet.class)){
  61             return (INeutronRequest<T>) new NeutronSubnetRequest((List<NeutronSubnet>) results.collection, results.links);
  62         }
  63         if (clazz.equals(NeutronPort.class)){
  64             return (INeutronRequest<T>) new NeutronPortRequest((List<NeutronPort>) results.collection, results.links);
  65         }
  66         return null;
  67     }
  68
  69     private static <T extends INeutronObject> PaginationResults<T> _paginate(Integer limit, String marker, Boolean pageReverse, UriInfo uriInfo, List<T> collection) {
  70         List<NeutronPageLink> links = new ArrayList<>();
  71         Integer startPos = null;
  72         String startMarker;
  73         String endMarker;
  74         Boolean firstPage = false;
  75         Boolean lastPage = false;
  76
  77         Collections.sort(collection, NEUTRON_OBJECT_COMPARATOR);
  78
  79         if (marker == null) {
  80             startPos = 0;
  81         }
  82
  83         else {
  84
  85             class MarkerObject implements INeutronObject {
  86                 private String id;
  87
  88                 @Override
  89                 public String getID() {
  90                     return id;
  91                 }
  92
  93                 @Override
  94                 public void setID(String id) {
  95                     this.id = id;
  96                 }
  97             }
  98
  99             INeutronObject markerObject = new MarkerObject();
 100
 101             markerObject.setID(marker);
 102
 103             startPos = Collections.binarySearch(collection, markerObject, NEUTRON_OBJECT_COMPARATOR);
 104
 105             if (!pageReverse){
 106                 startPos = startPos + 1;
 107             }
 108             else {
 109                 startPos = startPos - limit;
 110             }
 111
 112         }
 113
 114         if (startPos == null) {
 115             throw new ResourceNotFoundException("UUID for marker:" + marker + " could not be found");
 116         }
 117
 118         if (startPos == 0){
 119             firstPage = true;
 120         }
 121
 122         if (startPos + limit >= collection.size()) {
 123             collection = collection.subList(startPos, collection.size());
 124             startMarker = collection.get(0).getID();
 125             endMarker = collection.get(collection.size() - 1).getID();
 126             lastPage = true;
 127         }
 128         else if (startPos < 0) {
 129             if (startPos + limit > 0) {
 130                 collection = collection.subList(0, startPos + limit);
 131                 startMarker = collection.get(0).getID();
 132                 endMarker = collection.get(collection.size() - 1).getID();
 133                 firstPage = true;
 134             }
 135             else {
 136                 throw new BadRequestException("Requested page is out of bounds. Please check the supplied limit and marker");
 137             }
 138         }
 139         else {
 140             collection = collection.subList(startPos, startPos + limit);
 141             startMarker = collection.get(0).getID();
 142             endMarker = collection.get(limit-1).getID();
 143         }
 144
 145         if (!lastPage) {
 146             NeutronPageLink next = new NeutronPageLink();
 147             next.setRef("next");
 148             next.setHref(uriInfo.getAbsolutePath().toString() + "?limit=" + limit.toString() + "&marker=" + endMarker);
 149             links.add(next);
 150         }
 151
 152         if (!firstPage) {
 153             NeutronPageLink previous = new NeutronPageLink();
 154             previous.setRef("previous");
 155             previous.setHref(uriInfo.getAbsolutePath().toString() + "?limit=" + limit.toString() + "&marker=" + startMarker + "&page_reverse=True");
 156             links.add(previous);
 157         }
 158
 159         return new PaginationResults<T>(collection, links);
 160     }
 161 }