Adding dynamo support.

1 files changed, 109 insertions, 0 deletions

diff --git a/src/com/p4square/grow/backend/dynamo/DynamoCollectionProviderImpl.java b/src/com/p4square/grow/backend/dynamo/DynamoCollectionProviderImpl.java
new file mode 100644
index 0000000..b53e9f7
--- /dev/null
+++ b/src/com/p4square/grow/backend/dynamo/DynamoCollectionProviderImpl.java
@@ -0,0 +1,109 @@
+/*
+ * Copyright 2014 Jesse Morgan
+ */
+
+package com.p4square.grow.backend.dynamo;
+
+import java.io.IOException;
+
+import java.util.Collections;
+import java.util.LinkedHashMap;
+import java.util.Map;
+
+import com.p4square.grow.provider.CollectionProvider;
+import com.p4square.grow.provider.JsonEncodedProvider;
+
+/**
+ * 
+ * @author Jesse Morgan <jesse@jesterpm.net>
+ */
+public class DynamoCollectionProviderImpl<V> implements CollectionProvider<String, String, V> {
+    private final DynamoDatabase mDb;
+    private final String mTable;
+    private final Class<V> mClazz;
+
+    public DynamoCollectionProviderImpl(DynamoDatabase db, String table, Class<V> clazz) {
+        mDb = db;
+        mTable = table;
+        mClazz = clazz;
+    }
+
+    @Override
+    public V get(String collection, String key) throws IOException {
+        String blob = mDb.getAttribute(DynamoKey.newAttributeKey(mTable, collection, key));
+        return decode(blob);
+    }
+
+    @Override
+    public Map<String, V> query(String collection) throws IOException {
+        return query(collection, -1);
+    }
+
+    @Override
+    public Map<String, V> query(String collection, int limit) throws IOException {
+        Map<String, V> result = new LinkedHashMap<>();
+
+        Map<String, String> row = mDb.getKey(DynamoKey.newKey(mTable, collection));
+        if (row.size() > 0) {
+            int count = 0;
+            for (Map.Entry<String, String> c : row.entrySet()) {
+                if (limit >= 0 && ++count > limit) {
+                    break; // Limit reached.
+                }
+
+                String key = c.getKey();
+                String blob = c.getValue();
+                V obj = decode(blob);
+
+                result.put(key, obj);
+            }
+        }
+
+        return Collections.unmodifiableMap(result);
+    }
+
+    @Override
+    public void put(String collection, String key, V obj) throws IOException {
+        if (obj == null) {
+            mDb.deleteAttribute(DynamoKey.newAttributeKey(mTable, collection, key));
+        } else {
+            String blob = encode(obj);
+            mDb.putAttribute(DynamoKey.newAttributeKey(mTable, collection, key), blob);
+        }
+    }
+
+    /**
+     * Encode the object as JSON.
+     *
+     * @param obj The object to encode.
+     * @return The JSON encoding of obj.
+     * @throws IOException if the object cannot be encoded.
+     */
+    protected String encode(V obj) throws IOException {
+        if (mClazz == String.class) {
+            return (String) obj;
+        } else {
+            return JsonEncodedProvider.MAPPER.writeValueAsString(obj);
+        }
+    }
+
+    /**
+     * Decode the JSON string as an object.
+     *
+     * @param blob The JSON data to decode.
+     * @return The decoded object or null if blob is null.
+     * @throws IOException If an object cannot be decoded.
+     */
+    protected V decode(String blob) throws IOException {
+        if (blob == null) {
+            return null;
+        }
+
+        if (mClazz == String.class) {
+            return (V) blob;
+        }
+
+        V obj = JsonEncodedProvider.MAPPER.readValue(blob, mClazz);
+        return obj;
+    }
+}