[api] Adds IdentityBlockFactory for demo/test purpose (#1854)

Change-Id: I51eaedafec628d326af66f61ffc1f7c65a7c6b52

api/src/main/java/ai/djl/nn/IdentityBlockFactory.java

@@ -0,0 +1,30 @@
+/*
+ * Copyright 2022 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"). You may not use this file except in compliance
+ * with the License. A copy of the License is located at
+ *
+ * http://aws.amazon.com/apache2.0/
+ *
+ * or in the "license" file accompanying this file. This file is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES
+ * OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions
+ * and limitations under the License.
+ */
+package ai.djl.nn;
+
+import ai.djl.Model;
+
+import java.nio.file.Path;
+import java.util.Map;
+
+/** A {@link BlockFactory} class that creates IdentityBlock. */
+public class IdentityBlockFactory implements BlockFactory {
+
+    private static final long serialVersionUID = 1L;
+
+    /** {@inheritDoc} */
+    @Override
+    public Block newBlock(Model model, Path modelPath, Map<String, ?> arguments) {
+        return Blocks.identityBlock();
+    }
+}

api/src/test/java/ai/djl/nn/BlockFactoryTest.java

@@ -0,0 +1,34 @@
+/*
+ * Copyright 2022 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"). You may not use this file except in compliance
+ * with the License. A copy of the License is located at
+ *
+ * http://aws.amazon.com/apache2.0/
+ *
+ * or in the "license" file accompanying this file. This file is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES
+ * OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions
+ * and limitations under the License.
+ */
+package ai.djl.nn;
+
+import ai.djl.Model;
+
+import org.testng.Assert;
+import org.testng.annotations.Test;
+
+import java.nio.file.Path;
+import java.nio.file.Paths;
+
+public class BlockFactoryTest {
+
+    @Test
+    public void testIdentityBlockFactory() {
+        IdentityBlockFactory factory = new IdentityBlockFactory();
+        try (Model model = Model.newInstance("identity")) {
+            Path path = Paths.get("build");
+            Block block = factory.newBlock(model, path, null);
+            Assert.assertEquals(((LambdaBlock) block).getName(), "identity");
+        }
+    }
+}

api/src/test/java/ai/djl/nn/package-info.java

@@ -0,0 +1,15 @@
+/*
+ * Copyright 2022 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"). You may not use this file except in compliance
+ * with the License. A copy of the License is located at
+ *
+ * http://aws.amazon.com/apache2.0/
+ *
+ * or in the "license" file accompanying this file. This file is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES
+ * OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions
+ * and limitations under the License.
+ */
+
+/** Contains tests for {@link ai.djl.nn}. */
+package ai.djl.nn;

model-zoo/src/main/java/ai/djl/basicmodelzoo/basic/MlpBlockFactory.java

@@ -18,6 +18,7 @@
 import ai.djl.translate.ArgumentsUtil;
 
 import java.nio.file.Path;
+import java.util.Arrays;
 import java.util.List;
 import java.util.Map;
 
@@ -34,9 +35,16 @@ public Block newBlock(Model model, Path modelPath, Map<String, ?> arguments) {
         int height = ArgumentsUtil.intValue(arguments, "height", 28);
         int output = ArgumentsUtil.intValue(arguments, "output", 10);
         int input = width * height;
-        int[] hidden =
-                ((List<Double>) arguments.get("hidden"))
-                        .stream().mapToInt(Double::intValue).toArray();
+        Object hiddenValue = arguments.get("hidden");
+        int[] hidden;
+        if (hiddenValue == null) {
+            hidden = new int[] {128, 64};
+        } else if (hiddenValue instanceof List) {
+            hidden = ((List<Double>) hiddenValue).stream().mapToInt(Double::intValue).toArray();
+        } else {
+            String[] v = ((String) hiddenValue).split(",");
+            hidden = Arrays.stream(v).mapToInt(Integer::parseInt).toArray();
+        }
 
         return new Mlp(input, output, hidden);
     }