1 files changed, 70 insertions, 0 deletions
diff --git a/bundles/org.eclipse.equinox.p2.touchpoint.eclipse/src/org/eclipse/equinox/internal/p2/update/ConfigurationCache.java b/bundles/org.eclipse.equinox.p2.touchpoint.eclipse/src/org/eclipse/equinox/internal/p2/update/ConfigurationCache.java
new file mode 100644
index 000000000..53c5c65f5
--- /dev/null
+++ b/bundles/org.eclipse.equinox.p2.touchpoint.eclipse/src/org/eclipse/equinox/internal/p2/update/ConfigurationCache.java
@@ -0,0 +1,70 @@
+/*******************************************************************************
+ * Copyright (c) 2009 IBM Corporation and others.
+ * All rights reserved. This program and the accompanying materials 
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ * 
+ * Contributors:
+ *     IBM Corporation - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.equinox.internal.p2.update;
+
+import java.io.File;
+import java.io.IOException;
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * TODO ensure thread safety
+ *
+ */
+public class ConfigurationCache {
+	private static Map<String, CacheEntry> cache = new HashMap<String, CacheEntry>();
+
+	// class used to represent cache values
+	static class CacheEntry {
+		long timestamp;
+		Configuration config;
+	}
+
+	// helper method to convert the file to a cache key. convert to an absolute
+	// path to ensure equality between relative and absolute comparisons
+	private static String toKey(File file) {
+		try {
+			return file.getCanonicalPath();
+		} catch (IOException e) {
+			// ignore and return the absolute value instead
+		}
+		return file.getAbsolutePath();
+	}
+
+	/*
+	 * Return the configuration object in the cache which is represented
+	 * by the given file. Do a check on disk to see if the cache is up-to-date.
+	 * If not, then treat it as a cache miss.
+	 */
+	public static Configuration get(File file) {
+		String key = toKey(file);
+		CacheEntry entry = cache.get(key);
+		if (entry == null)
+			return null;
+		return file.lastModified() == entry.timestamp ? entry.config : null;
+	}
+
+	/*
+	 * Store the given configuration in the cache.
+	 */
+	public static void put(File file, Configuration config) {
+		String key = toKey(file);
+		if (config == null) {
+			cache.remove(key);
+			return;
+		}
+		CacheEntry entry = new CacheEntry();
+		entry.config = config;
+		entry.timestamp = file.lastModified();
+		cache.put(key, entry);
+	}
+
+}