summaryrefslogtreecommitdiffstats
path: root/java/com/google/gerrit/index/query/AndSource.java
blob: ebd115bcf4a2866d7eabefa1a7995fe058d3eb9d (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
// Copyright (C) 2016 The Android Open Source Project
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package com.google.gerrit.index.query;

import static com.google.common.base.Preconditions.checkArgument;

import com.google.common.collect.ImmutableList;
import com.google.gerrit.index.IndexConfig;
import java.util.Collection;
import java.util.List;

public class AndSource<T> extends AndPredicate<T> implements DataSource<T> {
  protected final DataSource<T> source;

  private final IsVisibleToPredicate<T> isVisibleToPredicate;
  private final int start;
  private final int cardinality;
  private final IndexConfig indexConfig;

  public AndSource(Collection<? extends Predicate<T>> that, IndexConfig indexConfig) {
    this(that, null, 0, indexConfig);
  }

  public AndSource(
      Predicate<T> that, IsVisibleToPredicate<T> isVisibleToPredicate, IndexConfig indexConfig) {
    this(that, isVisibleToPredicate, 0, indexConfig);
  }

  public AndSource(
      Predicate<T> that,
      IsVisibleToPredicate<T> isVisibleToPredicate,
      int start,
      IndexConfig indexConfig) {
    this(ImmutableList.of(that), isVisibleToPredicate, start, indexConfig);
  }

  public AndSource(
      Collection<? extends Predicate<T>> that,
      IsVisibleToPredicate<T> isVisibleToPredicate,
      int start,
      IndexConfig indexConfig) {
    super(that);
    checkArgument(start >= 0, "negative start: %s", start);
    this.isVisibleToPredicate = isVisibleToPredicate;
    this.start = start;
    this.indexConfig = indexConfig;

    int c = Integer.MAX_VALUE;
    Predicate<T> selectedSource = null;
    int minCardinality = Integer.MAX_VALUE;
    for (Predicate<T> p : getChildren()) {
      if (p instanceof DataSource) {
        DataSource<?> source = (DataSource<?>) p;
        int cardinality = source.getCardinality();
        c = Math.min(c, source.getCardinality());

        if (selectedSource == null
            || cardinality < minCardinality
            || (cardinality == minCardinality
                && p.estimateCost() < selectedSource.estimateCost())) {
          selectedSource = p;
          minCardinality = cardinality;
        }
      }
    }
    if (selectedSource == null) {
      throw new IllegalArgumentException("No DataSource Found");
    }
    this.source = toPaginatingSource(selectedSource);
    this.cardinality = c;
  }

  @Override
  public ResultSet<T> read() {
    return source.read();
  }

  @Override
  public ResultSet<FieldBundle> readRaw() {
    return source.readRaw();
  }

  @Override
  public boolean isMatchable() {
    return isVisibleToPredicate != null || super.isMatchable();
  }

  @Override
  public boolean match(T object) {
    if (isVisibleToPredicate != null && !isVisibleToPredicate.match(object)) {
      return false;
    }

    if (super.isMatchable() && !super.match(object)) {
      return false;
    }

    return true;
  }

  protected List<T> transformBuffer(List<T> buffer) {
    return buffer;
  }

  @Override
  public int getCardinality() {
    return cardinality;
  }

  @SuppressWarnings("unchecked")
  private PaginatingSource<T> toPaginatingSource(Predicate<T> pred) {
    return new PaginatingSource<T>((DataSource<T>) pred, start, indexConfig) {
      @Override
      protected boolean match(T object) {
        return AndSource.this.match(object);
      }

      @Override
      protected boolean isMatchable() {
        return AndSource.this.isMatchable();
      }
    };
  }
}