1 files changed, 69 insertions, 0 deletions
diff --git a/src/main/java/com/p4square/grow/provider/DelegateCollectionProvider.java b/src/main/java/com/p4square/grow/provider/DelegateCollectionProvider.java
new file mode 100644
index 0000000..cf697ba
--- /dev/null
+++ b/src/main/java/com/p4square/grow/provider/DelegateCollectionProvider.java
@@ -0,0 +1,69 @@
+/*
+ * Copyright 2014 Jesse Morgan
+ */
+
+package com.p4square.grow.provider;
+
+import java.io.IOException;
+import java.util.LinkedHashMap;
+import java.util.Map;
+
+/**
+ *
+ * @author Jesse Morgan <jesse@jesterpm.net>
+ */
+public abstract class DelegateCollectionProvider<C, DC, K, DK, V>
+    implements CollectionProvider<C, K, V> {
+
+    private CollectionProvider<DC, DK, V> mProvider;
+
+    public DelegateCollectionProvider(final CollectionProvider<DC, DK, V> provider) {
+        mProvider = provider;
+    }
+
+    public V get(C collection, K key) throws IOException {
+        return mProvider.get(makeCollectionKey(collection), makeKey(key));
+    }
+
+    public Map<K, V> query(C collection) throws IOException {
+        return query(collection, -1);
+    }
+
+    public Map<K, V> query(C collection, int limit) throws IOException {
+        Map<DK, V> delegateResult =  mProvider.query(makeCollectionKey(collection), limit);
+        Map<K, V> result = new LinkedHashMap<>();
+        for (Map.Entry<DK, V> entry : delegateResult.entrySet()) {
+            result.put(unmakeKey(entry.getKey()), entry.getValue());
+        }
+
+        return result;
+    }
+
+    public void put(C collection, K key, V obj) throws IOException {
+        mProvider.put(makeCollectionKey(collection), makeKey(key), obj);
+    }
+
+    /**
+     * Make a collection key for the delegated provider.
+     *
+     * @param input The pre-transform key.
+     * @return the post-transform key.
+     */
+    protected abstract DC makeCollectionKey(final C input);
+
+    /**
+     * Make a key for the delegated provider.
+     *
+     * @param input The pre-transform key.
+     * @return the post-transform key.
+     */
+    protected abstract DK makeKey(final K input);
+
+    /**
+     * Transform a key for the delegated provider to an input key.
+     *
+     * @param input The post-transform key.
+     * @return the pre-transform key.
+     */
+    protected abstract K unmakeKey(final DK input);
+}