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8187653: Lock in CoderResult.Cache becomes performance bottleneck

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Reviewed-by: rriggs, alanb
This commit is contained in:
Xueming Shen 2018-03-01 12:31:24 -08:00
parent b4d4d8f66c
commit 3a03cd060f
1 changed files with 28 additions and 10 deletions

38
src/java.base/share/classes/java/nio/charset/CoderResult.java

@ -1,5 +1,5 @@
/*
* Copyright (c) 2001, 2013, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2001, 2018, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
@ -27,9 +27,8 @@ package java.nio.charset;
import java.lang.ref.WeakReference;
import java.nio.*;
import java.util.concurrent.ConcurrentHashMap;
import java.util.Map;
import java.util.HashMap;
/**
* A description of the result state of a coder.
@ -197,14 +196,12 @@ public class CoderResult {
protected abstract CoderResult create(int len);
private synchronized CoderResult get(int len) {
if (len <= 0)
throw new IllegalArgumentException("Non-positive length");
private CoderResult get(int len) {
Integer k = len;
WeakReference<CoderResult> w;
CoderResult e = null;
if (cache == null) {
cache = new HashMap<>();
cache = new ConcurrentHashMap<>();
} else if ((w = cache.get(k)) != null) {
e = w.get();
}
@ -214,15 +211,21 @@ public class CoderResult {
}
return e;
}
}
private static Cache malformedCache
private static final Cache malformedCache
= new Cache() {
public CoderResult create(int len) {
return new CoderResult(CR_MALFORMED, len);
}};
private static final CoderResult[] malformed4 = new CoderResult[] {
new CoderResult(CR_MALFORMED, 1),
new CoderResult(CR_MALFORMED, 2),
new CoderResult(CR_MALFORMED, 3),
new CoderResult(CR_MALFORMED, 4),
};
/**
* Static factory method that returns the unique object describing a
* malformed-input error of the given length.
@ -233,15 +236,26 @@ public class CoderResult {
* @return The requested coder-result object
*/
public static CoderResult malformedForLength(int length) {
if (length <= 0)
throw new IllegalArgumentException("Non-positive length");
if (length <= 4)
return malformed4[length - 1];
return malformedCache.get(length);
}
private static Cache unmappableCache
private static final Cache unmappableCache
= new Cache() {
public CoderResult create(int len) {
return new CoderResult(CR_UNMAPPABLE, len);
}};
private static final CoderResult[] unmappable4 = new CoderResult[] {
new CoderResult(CR_UNMAPPABLE, 1),
new CoderResult(CR_UNMAPPABLE, 2),
new CoderResult(CR_UNMAPPABLE, 3),
new CoderResult(CR_UNMAPPABLE, 4),
};
/**
* Static factory method that returns the unique result object describing
* an unmappable-character error of the given length.
@ -252,6 +266,10 @@ public class CoderResult {
* @return The requested coder-result object
*/
public static CoderResult unmappableForLength(int length) {
if (length <= 0)
throw new IllegalArgumentException("Non-positive length");
if (length <= 4)
return unmappable4[length - 1];
return unmappableCache.get(length);
}