Line data    Source code

       1             : // Copyright (C) 2016 The Android Open Source Project
       2             : //
       3             : // Licensed under the Apache License, Version 2.0 (the "License");
       4             : // you may not use this file except in compliance with the License.
       5             : // 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
      10             : // distributed under the License is distributed on an "AS IS" BASIS,
      11             : // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
      12             : // See the License for the specific language governing permissions and
      13             : // limitations under the License.
      14             : 
      15             : package com.google.gerrit.index;
      16             : 
      17             : import static com.google.common.base.Preconditions.checkArgument;
      18             : import static java.util.Objects.requireNonNull;
      19             : 
      20             : import com.google.common.collect.ImmutableSortedMap;
      21             : import com.google.common.collect.Iterables;
      22             : import com.google.gerrit.common.Nullable;
      23             : 
      24             : /**
      25             :  * Definitions of the various schema versions over a given Gerrit data type.
      26             :  *
      27             :  * <p>A <em>schema</em> is a description of the fields that are indexed over the given data type.
      28             :  * This class contains all the versions of a schema defined over its data type, exposed as a map of
      29             :  * version number to schema definition. If you are interested in the classes responsible for
      30             :  * backend-specific runtime implementations, see the implementations of {@link IndexDefinition}.
      31             :  */
      32             : public abstract class SchemaDefinitions<V> {
      33             :   private final String name;
      34             :   private final ImmutableSortedMap<Integer, Schema<V>> schemas;
      35             : 
      36         154 :   protected SchemaDefinitions(String name, Class<V> valueClass) {
      37         154 :     this.name = requireNonNull(name);
      38         154 :     this.schemas = SchemaUtil.schemasFromClass(getClass(), valueClass);
      39         154 :   }
      40             : 
      41             :   public final String getName() {
      42         152 :     return name;
      43             :   }
      44             : 
      45             :   /** Returns all schemas sorted by version (ascending). */
      46             :   public final ImmutableSortedMap<Integer, Schema<V>> getSchemas() {
      47         148 :     return schemas;
      48             :   }
      49             : 
      50             :   public final Schema<V> get(int version) {
      51           0 :     Schema<V> schema = schemas.get(version);
      52           0 :     checkArgument(schema != null, "Unrecognized %s schema version: %s", name, version);
      53           0 :     return schema;
      54             :   }
      55             : 
      56             :   public final Schema<V> getLatest() {
      57          32 :     return schemas.lastEntry().getValue();
      58             :   }
      59             : 
      60             :   @Nullable
      61             :   public final Schema<V> getPrevious() {
      62          10 :     if (schemas.size() <= 1) {
      63           0 :       return null;
      64             :     }
      65          10 :     return Iterables.get(schemas.descendingMap().values(), 1);
      66             :   }
      67             : }