Bug 550645 - Performance improvements to CaseInsensitiveDictionaryMap

Improve hashCode calculation to avoid Character.toUpper/LowerCase calls
for ASCII chars and make hashCode final for CaseInsensitiveKey

Improve put operations by not interning the key on every put.  It is now
up to the client to intern if necessary.  Updated ManifestElement to do
that for bundle manifest keys while parsing the bundle manifest.  Also
improved performance for keys that are not already present in the Map by
avoiding a call to remove first.

With these optimizations put together we should see ~4x perforamance
improvement in the usage of the CaseInsensitiveDictionaryMap by the
framework.


Change-Id: Ibe21780b2be95cecab994fa2ca2e817d7bab112c
Signed-off-by: Thomas Watson <tjwatson@us.ibm.com>

1 files changed, 36 insertions, 15 deletions

diff --git a/bundles/org.eclipse.osgi/container/src/org/eclipse/osgi/framework/util/CaseInsensitiveDictionaryMap.java b/bundles/org.eclipse.osgi/container/src/org/eclipse/osgi/framework/util/CaseInsensitiveDictionaryMap.java
index 73086a5d3..7f013b276 100644
--- a/bundles/org.eclipse.osgi/container/src/org/eclipse/osgi/framework/util/CaseInsensitiveDictionaryMap.java
+++ b/bundles/org.eclipse.osgi/container/src/org/eclipse/osgi/framework/util/CaseInsensitiveDictionaryMap.java
@@ -16,7 +16,16 @@ package org.eclipse.osgi.framework.util;
 
 import static java.util.Objects.requireNonNull;
 
-import java.util.*;
+import java.util.AbstractSet;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.Dictionary;
+import java.util.Enumeration;
+import java.util.HashMap;
+import java.util.Iterator;
+import java.util.Map;
+import java.util.Objects;
+import java.util.Set;
 import org.eclipse.osgi.internal.messages.Msg;
 import org.eclipse.osgi.util.NLS;
 
@@ -178,10 +187,14 @@ public class CaseInsensitiveDictionaryMap<K, V> extends Dictionary<K, V> impleme
 	public V put(K key, V value) {
 		requireNonNull(value);
 		if (key instanceof String) {
-			Object wrappedKey = keyWrap(((String) key).intern());
-			V previous = map.remove(wrappedKey); // remove so we put key into map
-			map.put(wrappedKey, value);
-			return previous;
+			Object wrappedKey = keyWrap(key);
+			V existing = map.put(wrappedKey, value);
+			if (existing != null) {
+				// must remove to replace key if case has changed
+				map.remove(wrappedKey);
+				map.put(wrappedKey, value);
+			}
+			return existing;
 		}
 		return map.put(requireNonNull(key), value);
 	}
@@ -388,25 +401,33 @@ public class CaseInsensitiveDictionaryMap<K, V> extends Dictionary<K, V> impleme
 		}
 	}
 
+	static int computeHashCode(String key) {
+		int h = 1;
+		for (char c : key.toCharArray()) {
+			if (c < 0x80) { // ASCII
+				if (c >= 'A' && c <= 'Z') {
+					c += 'a' - 'A'; // convert to ASCII lowercase
+				}
+			} else {
+				c = Character.toLowerCase(Character.toUpperCase(c));
+			}
+			h = 31 * h + c;
+		}
+		return h;
+	}
+
 	private static final class CaseInsensitiveKey {
 		final String key;
-		private transient int hashCode;
+		final private int hashCode;
 
 		CaseInsensitiveKey(String key) {
 			this.key = key;
+			this.hashCode = computeHashCode(key);
 		}
 
 		@Override
 		public int hashCode() {
-			int h = hashCode;
-			if (h != 0) {
-				return h;
-			}
-			h = 1;
-			for (char c : key.toCharArray()) {
-				h = 31 * h + Character.toLowerCase(Character.toUpperCase(c));
-			}
-			return hashCode = h;
+			return hashCode;
 		}
 
 		@Override