1 files changed, 94 insertions, 0 deletions
diff --git a/src/com/gitblit/utils/ObjectCache.java b/src/com/gitblit/utils/ObjectCache.java
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+++ b/src/com/gitblit/utils/ObjectCache.java
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+/*
+ * Copyright 2011 gitblit.com.
+ *
+ * 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.gitblit.utils;
+
+import java.io.Serializable;
+import java.util.Date;
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+
+/**
+ * Reusable coarse date-based object cache. The date precision is in
+ * milliseconds and in fast, concurrent systems this cache is too simplistic.
+ * However, for the cases where its being used in Gitblit this cache technique
+ * is just fine.
+ * 
+ * @author James Moger
+ * 
+ */
+public class ObjectCache<X> implements Serializable {
+
+	private static final long serialVersionUID = 1L;
+
+	private final Map<String, CachedObject<X>> cache = new ConcurrentHashMap<String, CachedObject<X>>();
+
+	private class CachedObject<Y> {
+
+		public final String name;
+
+		private volatile Date date;
+
+		private volatile Y object;
+
+		CachedObject(String name) {
+			this.name = name;
+			date = new Date(0);
+		}
+
+		@Override
+		public String toString() {
+			return getClass().getSimpleName() + ": " + name;
+		}
+	}
+
+	public boolean hasCurrent(String name, Date date) {
+		return cache.containsKey(name) && cache.get(name).date.compareTo(date) == 0;
+	}
+
+	public Date getDate(String name) {
+		return cache.get(name).date;
+	}
+
+	public X getObject(String name) {
+		if (cache.containsKey(name)) {
+			return cache.get(name).object;
+		}
+		return null;
+	}
+
+	public void updateObject(String name, X object) {
+		this.updateObject(name, new Date(), object);
+	}
+
+	public void updateObject(String name, Date date, X object) {
+		CachedObject<X> obj;
+		if (cache.containsKey(name)) {
+			obj = cache.get(name);
+		} else {
+			obj = new CachedObject<X>(name);
+			cache.put(name, obj);
+		}
+		obj.date = date;
+		obj.object = object;
+	}
+
+	public Object remove(String name) {
+		if (cache.containsKey(name)) {
+			return cache.remove(name).object;
+		}
+		return null;
+	}
+}