1 files changed, 124 insertions, 0 deletions
diff --git a/israfil-foundation-cache/src/main/java/net/israfil/foundation/caching/GenericFetcherCache.java b/israfil-foundation-cache/src/main/java/net/israfil/foundation/caching/GenericFetcherCache.java
new file mode 100644
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+++ b/israfil-foundation-cache/src/main/java/net/israfil/foundation/caching/GenericFetcherCache.java
@@ -0,0 +1,124 @@
+/*
+ * Copyright (c) 2006 Israfil Consulting Services Corporation
+ * Copyright (c) 2006 Christian Edward Gruber
+ * All Rights Reserved
+ * 
+ * This software is licensed under the Berkeley Standard Distribution license,
+ * (BSD license), as defined below:
+ * 
+ * Redistribution and use in source and binary forms, with or without 
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this 
+ *    list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice, 
+ *    this list of conditions and the following disclaimer in the documentation 
+ *    and/or other materials provided with the distribution.
+ * 3. Neither the name of Israfil Consulting Services nor the names of its contributors 
+ *    may be used to endorse or promote products derived from this software without 
+ *    specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND 
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 
+ * IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, 
+ * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, 
+ * OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 
+ * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY 
+ * OF SUCH DAMAGE.
+ * 
+ * $Id: GenericCache.java 129 2006-12-31 23:20:02Z cgruber $
+ */
+package net.israfil.foundation.caching;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+
+/**
+ * A non-thread-safe cache object
+ * 
+ * @author <a href="mailto:cgruber@israfil.net">Christian Edward Gruber</a>
+ */
+public class GenericFetcherCache implements FetcherCache {
+	
+	private Map<String,Object> _caches = new HashMap<String,Object>();
+		
+	/**
+	 * Retrieves an object from a path in the cache
+	 * @param cacheName A string identifying from which cache the object will be retrieved
+	 * @param An array of path items identifying the path through the map keys.
+	 */
+	public Object get(Fetcher fetcher, String cacheName, String itemKey, String ... path) {
+					
+		// Fetch the map containing the item.
+		Map<String,Object> cache = _getLocationInMap(_caches,new ArrayList<String>(_prepPathList(cacheName,path)));
+
+		// Get the item from the map
+		Object o = cache.get((itemKey==null) ? "__NULL__" : itemKey);
+		if (o == null) {
+			// Item doesn't exist, so try to fetch, then retrieve again.
+			fetcher.fetch();
+			o = cache.get((itemKey==null) ? "__NULL__" : itemKey);
+		}
+		return o;		
+	}
+	
+
+	/**
+	 * A method to set values within the cache, to be used by Fetcher implementations
+	 * in setting up the cache when they fetch.
+	 */
+	public void set(String cacheName, String itemKey, Object value, String ... path) {
+		List<String> pathList = _prepPathList(cacheName,path);
+		Map<String,Object> cache = _getLocationInMap(_caches,new ArrayList<String>(pathList));
+		cache.put(itemKey,value);
+	}
+
+	/**
+	 * Creates a List that contains the pathelements, starting from the 
+	 * cache name down to the bottom, but excluding the actual final path
+	 * item.
+	 */
+	static List<String> _prepPathList(String cacheName,String[] pathElements) {
+		List<String> pathList;
+		if (pathElements == null || pathElements.length < 1) {
+			pathList = new ArrayList<String>();
+		} else {
+			// Need to make this explicitly an arrayList, so that
+			// add(index,value) will work.
+			pathList = new ArrayList<String>(Arrays.asList(pathElements));
+		}
+		pathList.add(0,cacheName);	
+		return pathList;
+	}
+	
+	/**
+	 * Recursively traverses the cache map, creating maps at path locations
+	 * where they do not already exist.
+	 */
+	@SuppressWarnings("unchecked")
+    static Map<String, Object> _getLocationInMap(
+            Map<String, Object> currentMap, List<String> cachePath) {
+		if (cachePath == null || cachePath.size() < 1) return currentMap;
+		String cacheName = (String)cachePath.remove(0); // pull the first one
+		
+		Object cacheObject = (Map<String,Object>)currentMap.get(cacheName);
+		if (cacheObject == null) {
+			cacheObject = new HashMap<String,Object>();
+			currentMap.put(cacheName,cacheObject);
+		}
+		if (! (cacheObject instanceof Map))
+			throw new IllegalArgumentException("Attempted to find a map at location ("+cachePath+") in cache ("+cacheName+"), but found a " + cacheObject.getClass().getName() + ".");
+		Map<String,Object> cache = (Map<String,Object>)cacheObject;
+		
+		return _getLocationInMap(cache,cachePath);
+	}
+
+	
+}