java/src/main/com/google/appengine/api/datastore/Index.java

   1 /*
   2  * Copyright 2011 Google Inc.
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
   5  * in compliance with the License. You may obtain a copy of the License at
   6  *
   7  * http://www.apache.org/licenses/LICENSE-2.0
   8  *
   9  * Unless required by applicable law or agreed to in writing, software distributed under the License
  10  * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
  11  * or implied. See the License for the specific language governing permissions and limitations under
  12  * the License.
  13  */
  14 package com.google.appengine.api.datastore;
  15
  16 import com.google.appengine.api.datastore.Query.SortDirection;
  17
  18 import java.io.Serializable;
  19 import java.util.Collections;
  20 import java.util.List;
  21 import java.util.Objects;
  22
  23 /**
  24  * A Datastore {@code Index} definition.
  25  *
  26  */
  27 public final class Index implements Serializable {
  28
  29   /**
  30    * Indicates the state of the {@link Index}.
  31    */
  32   public enum IndexState {
  33     /**
  34      * Indicates the given {@link Index} is being built and therefore can not
  35      * be used to service queries.
  36      */
  37     BUILDING,
  38     /**
  39      * Indicates the given {@link Index} is ready to service queries.
  40      */
  41     SERVING,
  42     /**
  43      * Indicates the given {@link Index} is being deleted.
  44      */
  45     DELETING,
  46     /**
  47      * Indicates the given {@link Index} encountered an error in the
  48      * {@code BUILDING} state.
  49      */
  50     ERROR
  51   }
  52
  53   /**
  54    * An indexed property.
  55    */
  56   public static class Property implements Serializable {
  57
  58     private static final long serialVersionUID = -5946842287951548217L;
  59
  60     private String name;
  61     private SortDirection direction;
  62
  63     @SuppressWarnings("unused")
  64     private Property() {}
  65
  66     /**
  67      * Constructs a new unmodifiable {@code Property} object.
  68      *
  69      * @param name the property name
  70      * @param direction the sort order for this property
  71      */
  72     Property(String name, SortDirection direction) {
  73       if (name == null) {
  74         throw new NullPointerException("name must not be null");
  75       }
  76       this.name = name;
  77       this.direction = direction;
  78     }
  79
  80     public String getName() {
  81       return name;
  82     }
  83
  84     public SortDirection getDirection() {
  85       return direction;
  86     }
  87
  88     @Override
  89     public boolean equals(Object obj) {
  90       if (obj instanceof Property) {
  91         Property other = (Property) obj;
  92         return name.equals(other.name) && Objects.equals(direction, other.direction);
  93       }
  94       return false;
  95     }
  96
  97     @Override
  98     public int hashCode() {
  99       return name.hashCode() * 31 + (direction == null ? 0 : direction.hashCode());
 100     }
 101
 102     @Override
 103     public String toString() {
 104       return name + " " + direction;
 105     }
 106   }
 107
 108   private static final long serialVersionUID = 8595801877003574982L;
 109
 110   private long id;
 111   private String kind;
 112   private boolean isAncestor;
 113   private List<Property> properties;
 114
 115   @SuppressWarnings("unused")
 116   private Index() {}
 117
 118   /**
 119    * Constructs a new unmodifiable {@code Index} object.
 120    *
 121    * @param id unique index identifier
 122    * @param kind specifies the kind of the entities to index
 123    * @param isAncestor true if the index supports a query that filters entities
 124    *    by the entity group parent, false otherwise.
 125    * @param properties the entity properties to index. The order of the
 126    *    {@code properties} elements specifies the order in the index.
 127    */
 128   Index(long id, String kind, boolean isAncestor, List<Property> properties) {
 129     if (kind == null) {
 130       throw new NullPointerException("kind must not be null");
 131     }
 132     if (properties == null) {
 133       throw new NullPointerException("properties must not be null");
 134     }
 135     this.id = id;
 136     this.kind = kind;
 137     this.isAncestor = isAncestor;
 138     this.properties = properties;
 139   }
 140
 141   public long getId() {
 142     return id;
 143   }
 144
 145   /**
 146    * Get the index's kind, or the empty string ("") if it has none.
 147    */
 148   public String getKind() {
 149     return kind;
 150   }
 151
 152   public boolean isAncestor() {
 153     return isAncestor;
 154   }
 155
 156   public List<Property> getProperties() {
 157     return Collections.unmodifiableList(properties);
 158   }
 159
 160   @Override
 161   public boolean equals(Object obj) {
 162     if (obj instanceof Index) {
 163       Index other = (Index) obj;
 164       return id == other.id
 165           && kind.equals(other.kind)
 166           && isAncestor == other.isAncestor
 167           && properties.equals(other.properties);
 168     }
 169     return false;
 170   }
 171
 172   @Override
 173   public int hashCode() {
 174     int result = Long.valueOf(id).hashCode();
 175     result = result * 31 + properties.hashCode();
 176     result = result * 31 + kind.hashCode();
 177     return result * 31 + Boolean.valueOf(isAncestor).hashCode();
 178   }
 179
 180   @Override
 181   public String toString() {
 182     StringBuilder stBuilder = new StringBuilder("INDEX [").append(id)
 183     .append("] ON ").append(kind).append('(');
 184     if (!properties.isEmpty()) {
 185       for (Property property : properties) {
 186         stBuilder.append(property).append(", ");
 187       }
 188       stBuilder.setLength(stBuilder.length() - 2);
 189     }
 190     stBuilder.append(")");
 191     if (isAncestor) {
 192       stBuilder.append(" INCLUDES ANCESTORS");
 193     }
 194     return stBuilder.toString();
 195   }
 196 }