1 files changed, 120 insertions, 0 deletions
diff --git a/jurt/com/sun/star/lib/uno/protocols/urp/Cache.java b/jurt/com/sun/star/lib/uno/protocols/urp/Cache.java
new file mode 100644
index 000000000000..48268a53a260
--- /dev/null
+++ b/jurt/com/sun/star/lib/uno/protocols/urp/Cache.java
@@ -0,0 +1,120 @@
+/*************************************************************************
+ *
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * Copyright 2000, 2010 Oracle and/or its affiliates.
+ *
+ * OpenOffice.org - a multi-platform office productivity suite
+ *
+ * This file is part of OpenOffice.org.
+ *
+ * OpenOffice.org is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License version 3
+ * only, as published by the Free Software Foundation.
+ *
+ * OpenOffice.org 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 Lesser General Public License version 3 for more details
+ * (a copy is included in the LICENSE file that accompanied this code).
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * version 3 along with OpenOffice.org.  If not, see
+ * <http://www.openoffice.org/license.html>
+ * for a copy of the LGPLv3 License.
+ *
+ ************************************************************************/
+
+package com.sun.star.lib.uno.protocols.urp;
+
+import java.util.HashMap;
+
+/**
+   An LRU cache for arbitrary objects.
+
+   This class is not synchronized, as any necessary synchronization will already
+   take place in the client.
+*/
+final class Cache {
+    /**
+       Create a cache.
+
+       @param size the maximum cache size, must be between 0, inclusive, and
+       NOT_CACHED, exclusive
+    */
+    public Cache(int size) {
+        maxSize = size;
+    }
+
+    public int add(boolean[] found, Object content) {
+        Entry e = (Entry) map.get(content);
+        found[0] = e != null;
+        if (e == null) {
+            if (map.size() < maxSize) {
+                // There is still room for a new entry at the front:
+                e = new Entry(content, map.size(), last, null);
+                if (first == null) {
+                    last = e;
+                } else {
+                    first.prev = e;
+                }
+                first = e;
+            } else if (last != null) {
+                // Take last entry out and recycle as new front:
+                map.remove(last.content);
+                e = last;
+                e.content = content;
+                if (first != last) {
+                    // Reached only if maxSize > 1:
+                    last = last.prev;
+                    last.next = null;
+                    e.prev = null;
+                    e.next = first;
+                    first.prev = e;
+                    first = e;
+                }
+            } else {
+                // Reached iff maxSize == 0:
+                return NOT_CACHED;
+            }
+            map.put(content, e);
+        } else if (e != first) {
+            // Move to front (reached only if maxSize > 1):
+            e.prev.next = e.next;
+            if (e.next == null) {
+                last = e.prev;
+            } else {
+                e.next.prev = e.prev;
+            }
+            e.prev = null;
+            e.next = first;
+            first.prev = e;
+            first = e;
+        }
+        return e.index;
+    }
+
+    public static final int NOT_CACHED = 0xFFFF;
+
+    private static final class Entry {
+        public Entry(Object content, int index, Entry prev, Entry next) {
+            this.content = content;
+            this.index = index;
+            this.prev = prev;
+            this.next = next;
+        }
+
+        public Object content;
+        public int index;
+        public Entry prev;
+        public Entry next;
+    }
+
+    // first/last form a list of 0 to maxSize entries, most recently used first;
+    // map contains the same entries; each entry has a unique index in the range
+    // 0 to maxSize - 1
+    private final int maxSize;
+    private final HashMap map = new HashMap(); // from Object to Entry
+    private Entry first = null;
+    private Entry last = null;
+}