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Prevent race condition in TypeHandlerRegistry #1820

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Merged
merged 3 commits into from
Jan 23, 2020
Merged

Prevent race condition in TypeHandlerRegistry #1820

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458809b
Prevent race condition in TypeHandlerRegistry
Jan 21, 2020
1f4528e
Prevent race condition in TypeHandlerRegistry - simplify
LyubinskiyPavel Jan 22, 2020
beeb15f
Polishing
harawata Jan 23, 2020
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4 changes: 2 additions & 2 deletions src/main/java/org/apache/ibatis/type/TypeHandlerRegistry.java
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Original file line number Diff line number Diff line change
@@ -1,5 +1,5 @@
/**
* Copyright 2009-2019 the original author or authors.
* Copyright 2009-2020 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
Expand Down Expand Up @@ -393,9 +393,9 @@ private void register(Type javaType, JdbcType jdbcType, TypeHandler<?> handler)
Map<JdbcType, TypeHandler<?>> map = typeHandlerMap.get(javaType);
if (map == null || map == NULL_TYPE_HANDLER_MAP) {
map = new HashMap<>();
typeHandlerMap.put(javaType, map);
}
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Wow...did this actually happen on production?

Regarding the change, how about updating typeHandlerMap at the end?
i.e.

      Map<JdbcType, TypeHandler<?>> map = typeHandlerMap.get(javaType);
      if (map == null || map == NULL_TYPE_HANDLER_MAP) {
        map = new HashMap<>();
      }
      map.put(jdbcType, handler);
      typeHandlerMap.put(javaType, map);

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Yep, this happening a couple times in a week on startup. But our apps work like as "lamba" (many cold startups in a loop).

I agree, this will save a couple of code lines 👍

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I see. That explains it.
The fix is merged and should be available in the latest 3.5.4-SNAPSHOT.
Please let me know if you noticed anything.

Thank you for the PR, @PVlyubinskiy !

map.put(jdbcType, handler);
typeHandlerMap.put(javaType, map);
}
allTypeHandlersMap.put(handler.getClass(), handler);
}
Expand Down
33 changes: 32 additions & 1 deletion src/test/java/org/apache/ibatis/type/TypeHandlerRegistryTest.java
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Original file line number Diff line number Diff line change
@@ -1,5 +1,5 @@
/**
* Copyright 2009-2019 the original author or authors.
* Copyright 2009-2020 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
Expand All @@ -24,6 +24,11 @@
import java.sql.SQLException;
import java.util.Date;
import java.util.List;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;
import java.util.stream.Collectors;
import java.util.stream.IntStream;

import org.apache.ibatis.domain.misc.RichType;
import org.junit.jupiter.api.BeforeEach;
Expand Down Expand Up @@ -215,4 +220,30 @@ class Address {
typeHandlerRegistry.register(Address.class, StringTypeHandler.class);
assertTrue(typeHandlerRegistry.hasTypeHandler(Address.class));
}

enum TestEnum {
ONE,
TWO
}

@Test
void shouldAutoRegisterEnutmTypeInMultiThreadEnvironment() throws Exception {
// gh-1820
ExecutorService executorService = Executors.newCachedThreadPool();
try {
for (int iteration = 0; iteration < 2000; iteration++) {
TypeHandlerRegistry typeHandlerRegistry = new TypeHandlerRegistry();
List<Future<Boolean>> taskResults = IntStream.range(0, 2)
.mapToObj(taskIndex -> executorService.submit(() -> {
return typeHandlerRegistry.hasTypeHandler(TestEnum.class, JdbcType.VARCHAR);
})).collect(Collectors.toList());
for (int i = 0; i < taskResults.size(); i++) {
Future<Boolean> future = taskResults.get(i);
assertTrue(future.get(), "false is returned at round " + iteration);
}
}
} finally {
executorService.shutdownNow();
}
}
}