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8215194: Initial size of UnicodeBlock map is incorrect

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Reviewed-by: rriggs, rgoel, igerasim
This commit is contained in:
Naoto Sato 2018-12-11 13:13:18 -08:00
parent 7cea6f6ac2
commit c2364ff9e0
2 changed files with 16 additions and 4 deletions
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5
src/java.base/share/classes/java/lang/Character.java
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@ -681,11 +681,12 @@ class Character implements java.io.Serializable, Comparable<Character> {
*/
public static final class UnicodeBlock extends Subset {
/**
* 649 - the expected number of entities
* 667 - the expected number of entities
* 0.75 - the default load factor of HashMap
*/
private static final int NUM_ENTITIES = 667;
private static Map<String, UnicodeBlock> map =
new HashMap<>((int)(649 / 0.75f + 1.0f));
new HashMap<>((int)(NUM_ENTITIES / 0.75f + 1.0f));
/**
* Creates a UnicodeBlock with the given identifier name.

15
test/jdk/java/lang/Character/UnicodeBlock/OptimalMapSize.java
View file

@ -23,7 +23,7 @@
/**
* @test
* @bug 8080535 8191410
* @bug 8080535 8191410 8215194
* @summary Expected size of Character.UnicodeBlock.map is not optimal
* @library /test/lib
* @modules java.base/java.lang:open
@ -32,6 +32,7 @@
* @run main OptimalMapSize
*/
import java.lang.reflect.Field;
import jdk.test.lib.util.OptimalCapacity;
// What will be the number of the Unicode blocks in the future.
@ -44,14 +45,24 @@ import jdk.test.lib.util.OptimalCapacity;
// After implementing support of Unicode 9 and 10 in Java, there will
// be 638 entries in Character.UnicodeBlock.map.
//
// As of Unicode 11, 667 entries are expected.
//
// Initialization of the map and this test will have to be adjusted
// accordingly then.
//
// Note that HashMap's implementation aligns the initial capacity to
// a power of two size, so it will end up 1024 (and thus succeed) in
// cases, such as 638 and 667.
public class OptimalMapSize {
public static void main(String[] args) throws Throwable {
// The initial size of Character.UnicodeBlock.map.
// See src/java.base/share/classes/java/lang/Character.java
int initialCapacity = (int)(638 / 0.75f + 1.0f);
Field f = Character.UnicodeBlock.class.getDeclaredField("NUM_ENTITIES");
f.setAccessible(true);
int num_entities = f.getInt(null);
assert num_entities == 667;
int initialCapacity = (int)(num_entities / 0.75f + 1.0f);
OptimalCapacity.ofHashMap(Character.UnicodeBlock.class,
"map", initialCapacity);