aboutsummaryrefslogtreecommitdiff
path: root/src/main/java/org/traccar/database/BaseObjectManager.java
blob: d0024c005e8f521bc5272e49d901248fc0430a67 (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
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
/*
 * Copyright 2017 - 2020 Anton Tananaev (anton@traccar.org)
 * Copyright 2017 Andrey Kunitsyn (andrey@traccar.org)
 *
 * 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 org.traccar.database;

import java.sql.SQLException;
import java.util.Collection;
import java.util.HashSet;
import java.util.LinkedList;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.locks.ReadWriteLock;
import java.util.concurrent.locks.ReentrantReadWriteLock;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.traccar.model.BaseModel;

public class BaseObjectManager<T extends BaseModel> {

    private static final Logger LOGGER = LoggerFactory.getLogger(BaseObjectManager.class);

    private final ReadWriteLock lock = new ReentrantReadWriteLock();

    private final DataManager dataManager;

    private Map<Long, T> items;
    private Class<T> baseClass;

    protected BaseObjectManager(DataManager dataManager, Class<T> baseClass) {
        this.dataManager = dataManager;
        this.baseClass = baseClass;
        refreshItems();
    }

    protected final void readLock() {
        lock.readLock().lock();
    }

    protected final void readUnlock() {
        lock.readLock().unlock();
    }

    protected final void writeLock() {
        lock.writeLock().lock();
    }

    protected final void writeUnlock() {
        lock.writeLock().unlock();
    }

    protected final DataManager getDataManager() {
        return dataManager;
    }

    protected final Class<T> getBaseClass() {
        return baseClass;
    }

    public T getById(long itemId) {
        try {
            readLock();
            return items.get(itemId);
        } finally {
            readUnlock();
        }
    }

    public void refreshItems() {
        if (dataManager != null) {
            try {
                writeLock();
                Collection<T> databaseItems = dataManager.getObjects(baseClass);
                if (items == null) {
                    items = new ConcurrentHashMap<>(databaseItems.size());
                }
                Set<Long> databaseItemIds = new HashSet<>();
                for (T item : databaseItems) {
                    databaseItemIds.add(item.getId());
                    if (items.containsKey(item.getId())) {
                        updateCachedItem(item);
                    } else {
                        addNewItem(item);
                    }
                }
                for (Long cachedItemId : items.keySet()) {
                    if (!databaseItemIds.contains(cachedItemId)) {
                        removeCachedItem(cachedItemId);
                    }
                }
            } catch (SQLException error) {
                LOGGER.warn("Error refreshing items", error);
            } finally {
                writeUnlock();
            }
        }
    }

    protected void addNewItem(T item) {
        try {
            writeLock();
            items.put(item.getId(), item);
        } finally {
            writeUnlock();
        }
    }

    public void addItem(T item) throws SQLException {
        dataManager.addObject(item);
        addNewItem(item);
    }

    protected void updateCachedItem(T item) {
        try {
            writeLock();
            items.put(item.getId(), item);
        } finally {
            writeUnlock();
        }
    }

    public void updateItem(T item) throws SQLException {
        dataManager.updateObject(item);
        updateCachedItem(item);
    }

    protected void removeCachedItem(long itemId) {
        try {
            writeLock();
            items.remove(itemId);
        } finally {
            writeUnlock();
        }
    }

    public void removeItem(long itemId) throws SQLException {
        BaseModel item = getById(itemId);
        if (item != null) {
            dataManager.removeObject(baseClass, itemId);
            removeCachedItem(itemId);
        }
    }

    public final Collection<T> getItems(Set<Long> itemIds) {
        Collection<T> result = new LinkedList<>();
        for (long itemId : itemIds) {
            T item = getById(itemId);
            if (item != null) {
                result.add(item);
            }
        }
        return result;
    }

    public Set<Long> getAllItems() {
        try {
            readLock();
            return items.keySet();
        } finally {
            readUnlock();
        }
    }

}