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Remove usage of StringPool as it appears to slow things down and avoid Java String intern for the common cases.

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This commit is contained in:
Joel Leitch 2013-04-08 18:36:23 +00:00
parent 83e1f45653
commit 70f9280cb6
2 changed files with 3 additions and 89 deletions
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27
gson/src/main/java/com/google/gson/stream/JsonReader.java
View File

@ -263,11 +263,6 @@ public class JsonReader implements Closeable {
*/
private String peekedString;
/**
* A pool of short strings intended to prevent object allocation.
*/
private static final StringPool stringPool = new StringPool();
/*
* The nesting stack. Using a manual array rather than an ArrayList saves 20%.
*/
@ -979,8 +974,7 @@ public class JsonReader implements Closeable {
private String nextQuotedValue(char quote) throws IOException {
// Like nextNonWhitespace, this uses locals 'p' and 'l' to save inner-loop field access.
char[] buffer = this.buffer;
StringBuilder builder = null;
int hashCode = 0;
StringBuilder builder = new StringBuilder();
while (true) {
int p = pos;
int l = limit;
@ -991,36 +985,21 @@ public class JsonReader implements Closeable {
if (c == quote) {
pos = p;
if (builder == null) {
return stringPool.get(buffer, start, p - start - 1, hashCode);
} else {
builder.append(buffer, start, p - start - 1);
return builder.toString();
}
builder.append(buffer, start, p - start - 1);
return builder.toString();
} else if (c == '\\') {
pos = p;
if (builder == null) {
builder = new StringBuilder();
}
builder.append(buffer, start, p - start - 1);
builder.append(readEscapeCharacter());
p = pos;
l = limit;
start = p;
} else if (c == '\n') {
hashCode = (hashCode * 31) + c;
lineNumber++;
lineStart = p;
} else {
hashCode = (hashCode * 31) + c;
}
}
if (builder == null) {
builder = new StringBuilder();
}
builder.append(buffer, start, p - start);
pos = p;
if (!fillBuffer(1)) {

65
gson/src/main/java/com/google/gson/stream/StringPool.java
View File

@ -1,65 +0,0 @@
/*
* Copyright (C) 2011 Google Inc.
*
* 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.gson.stream;
/**
* A pool of string instances. Unlike the {@link String#intern() VM's
* interned strings}, this pool provides no guarantee of reference equality.
* It is intended only to save allocations.
*
* <p>This class is safe for concurrent use.
*/
final class StringPool {
/**
* The maximum length of strings to add to the pool. Strings longer than this
* don't benefit from pooling because we spend more time on pooling than we
* save on garbage collection.
*/
private static final int MAX_LENGTH = 20;
private final String[] pool = new String[1024];
/**
* Returns a string equal to {@code new String(array, start, length)}.
*/
public String get(char[] array, int start, int length, int hashCode) {
if (length > StringPool.MAX_LENGTH) {
return new String(array, start, length);
}
// Pick a bucket using Doug Lea's supplemental secondaryHash function (from HashMap)
hashCode ^= (hashCode >>> 20) ^ (hashCode >>> 12);
hashCode ^= (hashCode >>> 7) ^ (hashCode >>> 4);
int index = hashCode & (pool.length - 1);
String pooled = pool[index];
if (pooled == null || pooled.length() != length) {
String result = new String(array, start, length);
pool[index] = result;
return result;
}
for (int i = 0; i < length; i++) {
if (pooled.charAt(i) != array[start + i]) {
String result = new String(array, start, length);
pool[index] = result;
return result;
}
}
return pooled;
}
}