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8149656: Examine usages of sun.misc.LRUCache

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Reviewed-by: redestad, rriggs
This commit is contained in:
Chris Hegarty 2016-02-15 10:14:39 +00:00
parent 8f6486a73b
commit 7f68f6d847
2 changed files with 47 additions and 89 deletions
jdk/src/java.base/share/classes
java/util
Scanner.java
sun/misc
LRUCache.java

58
jdk/src/java.base/share/classes/java/util/Scanner.java

@ -38,8 +38,6 @@ import java.util.regex.*;
import java.util.stream.Stream;
import java.util.stream.StreamSupport;
import sun.misc.LRUCache;
/**
* A simple text scanner which can parse primitive types and strings using
* regular expressions.
@ -366,15 +364,7 @@ public final class Scanner implements Iterator<String>, Closeable {
private Locale locale = null;
// A cache of the last few recently used Patterns
private LRUCache<String,Pattern> patternCache =
new LRUCache<String,Pattern>(7) {
protected Pattern create(String s) {
return Pattern.compile(s);
}
protected boolean hasName(Pattern p, String s) {
return p.pattern().equals(s);
}
};
private PatternLRUCache patternCache = new PatternLRUCache(7);
// A holder of the last IOException encountered
private IOException lastException;
@ -2838,4 +2828,50 @@ public final class Scanner implements Iterator<String>, Closeable {
}
}
}
/** Small LRU cache of Patterns. */
private static class PatternLRUCache {
private Pattern[] oa = null;
private final int size;
PatternLRUCache(int size) {
this.size = size;
}
boolean hasName(Pattern p, String s) {
return p.pattern().equals(s);
}
void moveToFront(Object[] oa, int i) {
Object ob = oa[i];
for (int j = i; j > 0; j--)
oa[j] = oa[j - 1];
oa[0] = ob;
}
Pattern forName(String name) {
if (oa == null) {
Pattern[] temp = new Pattern[size];
oa = temp;
} else {
for (int i = 0; i < oa.length; i++) {
Pattern ob = oa[i];
if (ob == null)
continue;
if (hasName(ob, name)) {
if (i > 0)
moveToFront(oa, i);
return ob;
}
}
}
// Create a new object
Pattern ob = Pattern.compile(name);
oa[oa.length - 1] = ob;
moveToFront(oa, oa.length - 1);
return ob;
}
}
}

78
jdk/src/java.base/share/classes/sun/misc/LRUCache.java

@ -1,78 +0,0 @@
/*
* Copyright (c) 2003, 2011, 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
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
package sun.misc;
/**
* Utility class for small LRU caches.
*
* @author Mark Reinhold
*/
public abstract class LRUCache<N,V> {
private V[] oa = null;
private final int size;
public LRUCache(int size) {
this.size = size;
}
protected abstract V create(N name);
protected abstract boolean hasName(V ob, N name);
public static void moveToFront(Object[] oa, int i) {
Object ob = oa[i];
for (int j = i; j > 0; j--)
oa[j] = oa[j - 1];
oa[0] = ob;
}
public V forName(N name) {
if (oa == null) {
@SuppressWarnings("unchecked")
V[] temp = (V[])new Object[size];
oa = temp;
} else {
for (int i = 0; i < oa.length; i++) {
V ob = oa[i];
if (ob == null)
continue;
if (hasName(ob, name)) {
if (i > 0)
moveToFront(oa, i);
return ob;
}
}
}
// Create a new object
V ob = create(name);
oa[oa.length - 1] = ob;
moveToFront(oa, oa.length - 1);
return ob;
}
}