Line data    Source code

       1             : // Copyright (C) 2022 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 com.google.gerrit.common.Nullable;
      18             : import java.io.IOException;
      19             : 
      20             : /** Interfaces that define properties of fields in {@link Schema}. */
      21           0 : public class SchemaFieldDefs {
      22             : 
      23             :   /**
      24             :    * Definition of a field stored in the secondary index.
      25             :    *
      26             :    * <p>{@link SchemaField}-s must not be changed once introduced to the codebase. Instead, a new
      27             :    * FieldDef must be added and the old one removed from the schema (in two upgrade steps, see
      28             :    * {@code com.google.gerrit.index.IndexUpgradeValidator}).
      29             :    *
      30             :    * @param <I> input type from which documents are created and search results are returned.
      31             :    * @param <T> type that should be extracted from the input object when converting to an index
      32             :    *     document.
      33             :    */
      34             :   public interface SchemaField<T, I> {
      35             : 
      36             :     /** Returns whether the field should be stored in the index. */
      37             :     boolean isStored();
      38             : 
      39             :     /** Returns whether the field is repeatable. */
      40             :     boolean isRepeatable();
      41             : 
      42             :     /**
      43             :      * Get the field contents from the input object.
      44             :      *
      45             :      * @param input input object.
      46             :      * @return the field value(s) to index.
      47             :      */
      48             :     @Nullable
      49             :     I get(T input);
      50             : 
      51             :     /** Returns the name of the field. */
      52             :     String getName();
      53             : 
      54             :     /**
      55             :      * Returns type of the field; for repeatable fields, the inner type, not the iterable type.
      56             :      * TODO(mariasavtchuk): remove after migrating to the new field formats
      57             :      */
      58             :     FieldType<?> getType();
      59             : 
      60             :     /**
      61             :      * Set the field contents back to an object. Used to reconstruct fields from indexed values.
      62             :      * No-op if the field can't be reconstructed.
      63             :      *
      64             :      * @param object input object.
      65             :      * @param doc indexed document
      66             :      * @return {@code true} if the field was set, {@code false} otherwise
      67             :      */
      68             :     boolean setIfPossible(T object, StoredValue doc);
      69             :   }
      70             : 
      71             :   /**
      72             :    * Getter to extract value that should be stored in index from the input object.
      73             :    *
      74             :    * <p>This interface allows to specify a method or lambda for populating an index field. Note that
      75             :    * for existing fields, changing the code of either the {@link Getter} implementation or the
      76             :    * method(s) that it calls would invalidate existing index data. Therefore, instead of changing
      77             :    * the semantics of an existing field, a new field must be added using the new semantics from the
      78             :    * start. The old field can be removed in another upgrade step (cf. {@code
      79             :    * com.google.gerrit.index.IndexUpgradeValidator}).
      80             :    *
      81             :    * @param <I> type from which documents are created and search results are returned.
      82             :    * @param <T> type that should be extracted from the input object to an index field.
      83             :    */
      84             :   @FunctionalInterface
      85             :   public interface Getter<I, T> {
      86             :     @Nullable
      87             :     T get(I input) throws IOException;
      88             :   }
      89             : 
      90             :   /**
      91             :    * Setter to reconstruct fields from indexed values back to an object.
      92             :    *
      93             :    * <p>See {@link Getter} for restrictions on changing the implementation.
      94             :    *
      95             :    * @param <I> type from which documents are created and search results are returned.
      96             :    * @param <T> type that should be extracted from the input object when converting toto an index
      97             :    *     field.
      98             :    */
      99             :   @FunctionalInterface
     100             :   public interface Setter<I, T> {
     101             :     void set(I object, T value);
     102             :   }
     103             : }