From 439a646b5edfde260d4b14821e6d7c18f819c7d7 Mon Sep 17 00:00:00 2001
From: Marko Živković <marko88zivkovic@gmail.com>
Date: Tue, 3 Mar 2015 00:51:20 +0000
Subject: add ObjectCache for StorableObjects

git-svn-id: https://svn.code.sf.net/p/xlogo4schools/svn/trunk@32 3b0d7934-f7ef-4143-9606-b51f2e2281fd
---
 logo/src/xlogo/storage/cache/ObjectCache.java | 91 +++++++++++++++++++++++++++
 1 file changed, 91 insertions(+)
 create mode 100644 logo/src/xlogo/storage/cache/ObjectCache.java

(limited to 'logo')

diff --git a/logo/src/xlogo/storage/cache/ObjectCache.java b/logo/src/xlogo/storage/cache/ObjectCache.java
new file mode 100644
index 0000000..0fc6a30
--- /dev/null
+++ b/logo/src/xlogo/storage/cache/ObjectCache.java
@@ -0,0 +1,91 @@
+package xlogo.storage.cache;
+
+import java.io.File;
+import java.util.HashMap;
+
+import xlogo.interfaces.Observable;
+import xlogo.storage.StorableObject;
+
+/**
+ * Cache {@link StorableObject} based on {@link StorableObject#getFilePath()}
+ * @author Marko
+ *
+ */
+public class ObjectCache {
+	
+	/*
+	 * Singleton
+	 */
+	
+	private static ObjectCache instance;
+	
+	public static final ObjectCache getInstance(){
+		if(instance == null){
+			instance = new ObjectCache();
+		}
+		return instance;
+	}
+	
+	/*
+	 * Cache fields
+	 */
+	
+	/**
+	 * Class of T -> Map({@link StorableObject#getFilePath()} -> {@link StorableObject} of T)
+	 */
+	private HashMap<Class<?>,HashMap<File,StorableObject<?,?>>> cache;
+	
+	private ObjectCache(){
+		cache = new HashMap<Class<?>, HashMap<File,StorableObject<?,?>>>();
+	}
+
+	/** 
+	 * Cache {@link StorableObject} based on {@link StorableObject#getFilePath()}
+	 * @param storable
+	 */
+	public <T extends Observable<?>> void cache(StorableObject<T,?> storable){
+		if (storable == null || storable.get() == null){
+			// TODO log warning
+			return;
+		}
+		Class<?> c = storable.get().getClass();
+		HashMap<File, StorableObject<?,?>> classCache = cache.get(c);
+		if (classCache == null){
+			classCache = new HashMap<File, StorableObject<?, ?>>();
+			cache.put(c, classCache);
+		}
+		classCache.put(storable.getFilePath(), storable);
+	}
+	
+	/**
+	 * 
+	 * @param file
+	 * @param c
+	 * @return
+	 */
+	@SuppressWarnings("unchecked") // implementation of cache guarantees that the cast succeeds
+	public <T extends Observable<E>,E extends Enum<E>> StorableObject<T, E> get(File file, Class<T> c){
+		HashMap<File, StorableObject<?, ?>> classCache = cache.get(c);
+		if (classCache == null){
+			return null;
+		}
+		return (StorableObject<T, E>) classCache.get(file);
+	}
+	
+	public <T extends Observable<?>> void remove(StorableObject<T,?> storable){
+		if (storable == null || storable.get() == null){
+			return;
+		}
+		Class<?> c = storable.get().getClass();
+		remove(storable.getFilePath(), c);
+	}
+	
+	public void remove(File file, Class<?> c){
+		HashMap<File, StorableObject<?,?>> classCache = cache.get(c);
+		if (classCache == null){
+			return;
+		}
+		classCache.remove(file);
+	}
+	
+}
-- 
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