HONEYCOMB-122 Update reader registry to share similar APIs as writer

+ Extract common registry builder base code
(Reader registry is not flat, so there is not full control over ordering as with writers
but it is sufficient)
+ Split CompositeReader into CompositeReader, SubtreeReader and GenericReader
+ No need to build composite structure in ReaderFactories (registry does that internally)
+ Keep only ReaderCustomizer + ListReaderCustomizer, no root reader (same for writers)

Change-Id: Ic4e5bc96ad47a6cbcada4efcc2209db5c16d2a6c
Signed-off-by: Maros Marsalek <mmarsale@cisco.com>

6 files changed, 30 insertions, 110 deletions

diff --git a/v3po/translate-spi/src/main/java/io/fd/honeycomb/v3po/translate/spi/read/ChildReaderCustomizer.java b/v3po/translate-spi/src/main/java/io/fd/honeycomb/v3po/translate/spi/read/ChildReaderCustomizer.java
deleted file mode 100644
index 8acc54db9..000000000
--- a/v3po/translate-spi/src/main/java/io/fd/honeycomb/v3po/translate/spi/read/ChildReaderCustomizer.java
+++ /dev/null
@@ -1,41 +0,0 @@
-/*
- * Copyright (c) 2016 Cisco and/or its affiliates.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at:
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License 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 io.fd.honeycomb.v3po.translate.spi.read;
-
-import com.google.common.annotations.Beta;
-import javax.annotation.Nonnull;
-import org.opendaylight.yangtools.concepts.Builder;
-import org.opendaylight.yangtools.yang.binding.DataObject;
-
-/**
- * CompositeChildReader SPI to customize its behavior
- *
- * @param <C> Specific DataObject derived type (Identifiable), that is handled by this customizer
- * @param <B> Specific Builder for handled type (C)
- */
-@Beta
-public interface ChildReaderCustomizer<C extends DataObject, B extends Builder<C>> extends
-    RootReaderCustomizer<C, B> {
-
-    // FIXME need to capture parent builder type, but that's inconvenient at best, is it ok to leave it Builder<?> and
-    // cast in specific customizers ? ... probably better than adding another type parameter
-
-    /**
-     * Merge read data into provided parent builder
-     */
-    void merge(@Nonnull final Builder<? extends DataObject> parentBuilder, @Nonnull final C readValue);
-}
diff --git a/v3po/translate-spi/src/main/java/io/fd/honeycomb/v3po/translate/spi/read/ListReaderCustomizer.java b/v3po/translate-spi/src/main/java/io/fd/honeycomb/v3po/translate/spi/read/ListReaderCustomizer.java
index 4a2e02cfb..59557554f 100644
--- a/v3po/translate-spi/src/main/java/io/fd/honeycomb/v3po/translate/spi/read/ListReaderCustomizer.java
+++ b/v3po/translate-spi/src/main/java/io/fd/honeycomb/v3po/translate/spi/read/ListReaderCustomizer.java
@@ -19,6 +19,7 @@ package io.fd.honeycomb.v3po.translate.spi.read;
 import com.google.common.annotations.Beta;
 import io.fd.honeycomb.v3po.translate.read.ReadContext;
 import io.fd.honeycomb.v3po.translate.read.ReadFailedException;
+import java.util.Collections;
 import java.util.List;
 import javax.annotation.Nonnull;
 import org.opendaylight.yangtools.concepts.Builder;
@@ -28,7 +29,7 @@ import org.opendaylight.yangtools.yang.binding.Identifier;
 import org.opendaylight.yangtools.yang.binding.InstanceIdentifier;
 
 /**
- * CompositeListReader SPI to customize its behavior
+ * CompositeListReader SPI to customize its behavior.
  *
  * @param <C> Specific DataObject derived type (Identifiable), that is handled by this customizer
  * @param <K> Specific Identifier for handled type (C)
@@ -36,7 +37,7 @@ import org.opendaylight.yangtools.yang.binding.InstanceIdentifier;
  */
 @Beta
 public interface ListReaderCustomizer<C extends DataObject & Identifiable<K>, K extends Identifier<C>, B extends Builder<C>>
-    extends RootReaderCustomizer<C, B> {
+    extends ReaderCustomizer<C, B> {
 
     /**
      * Return list with IDs of all list nodes to be read.
@@ -51,7 +52,12 @@ public interface ListReaderCustomizer<C extends DataObject & Identifiable<K>, K
     // TODO does it make sense with vpp APIs ? Should we replace it with a simple readAll ?
 
     /**
-     * Merge read data into provided parent builder
+     * Merge read data into provided parent builder.
      */
     void merge(@Nonnull final Builder<? extends DataObject> builder, @Nonnull final List<C> readData);
+
+    @Override
+    default void merge(@Nonnull final Builder<? extends DataObject> parentBuilder, @Nonnull final C readValue) {
+        merge(parentBuilder, Collections.singletonList(readValue));
+    }
 }
diff --git a/v3po/translate-spi/src/main/java/io/fd/honeycomb/v3po/translate/spi/read/RootReaderCustomizer.java b/v3po/translate-spi/src/main/java/io/fd/honeycomb/v3po/translate/spi/read/ReaderCustomizer.java
index f0cb76860..270da8beb 100644
--- a/v3po/translate-spi/src/main/java/io/fd/honeycomb/v3po/translate/spi/read/RootReaderCustomizer.java
+++ b/v3po/translate-spi/src/main/java/io/fd/honeycomb/v3po/translate/spi/read/ReaderCustomizer.java
@@ -25,13 +25,13 @@ import org.opendaylight.yangtools.yang.binding.DataObject;
 import org.opendaylight.yangtools.yang.binding.InstanceIdentifier;
 
 /**
- * CompositeRootReader SPI to customize its behavior
+ * CompositeChildReader SPI to customize its behavior.
  *
- * @param <C> Specific DataObject derived type, that is handled by this customizer
+ * @param <C> Specific DataObject derived type (Identifiable), that is handled by this customizer
  * @param <B> Specific Builder for handled type (C)
  */
 @Beta
-public interface RootReaderCustomizer<C extends DataObject, B extends Builder<C>> {
+public interface ReaderCustomizer<C extends DataObject, B extends Builder<C>> {
 
     /**
      * Creates new builder that will be used to build read value.
@@ -39,7 +39,6 @@ public interface RootReaderCustomizer<C extends DataObject, B extends Builder<C>
     @Nonnull
     B getBuilder(@Nonnull final InstanceIdentifier<C> id);
 
-
     /**
      * Adds current data (identified by id) to the provided builder.
      *
@@ -48,6 +47,17 @@ public interface RootReaderCustomizer<C extends DataObject, B extends Builder<C>
      * @param ctx
      * @throws ReadFailedException if read was unsuccessful
      */
-    void readCurrentAttributes(@Nonnull final InstanceIdentifier<C> id, @Nonnull final B builder,
+    void readCurrentAttributes(@Nonnull final InstanceIdentifier<C> id,
+                               @Nonnull final B builder,
                                @Nonnull final ReadContext ctx) throws ReadFailedException;
+
+    // FIXME need to capture parent builder type, but that's inconvenient at best, is it ok to leave it Builder<?> and
+    // cast in specific customizers ? ... probably better than adding another type parameter
+
+    /**
+     * Merge read data into provided parent builder.
+     */
+    void merge(@Nonnull final Builder<? extends DataObject> parentBuilder, @Nonnull final C readValue);
+
+
 }
diff --git a/v3po/translate-spi/src/main/java/io/fd/honeycomb/v3po/translate/spi/write/ChildWriterCustomizer.java b/v3po/translate-spi/src/main/java/io/fd/honeycomb/v3po/translate/spi/write/ChildWriterCustomizer.java
deleted file mode 100644
index e8f248495..000000000
--- a/v3po/translate-spi/src/main/java/io/fd/honeycomb/v3po/translate/spi/write/ChildWriterCustomizer.java
+++ /dev/null
@@ -1,42 +0,0 @@
-/*
- * Copyright (c) 2016 Cisco and/or its affiliates.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at:
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License 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 io.fd.honeycomb.v3po.translate.spi.write;
-
-import com.google.common.annotations.Beta;
-import com.google.common.base.Optional;
-import javax.annotation.Nonnull;
-import org.opendaylight.yangtools.yang.binding.DataObject;
-import org.opendaylight.yangtools.yang.binding.InstanceIdentifier;
-
-/**
- * CompositeChildWriter SPI to customize its behavior
- *
- * @param <D> Specific DataObject derived type (Identifiable), that is handled by this customizer
- */
-@Beta
-public interface ChildWriterCustomizer<D extends DataObject> extends RootWriterCustomizer<D> {
-
-    /**
-     * Get child of parentData identified by currentId
-     *
-     * @param currentId Identifier(from root) of data being extracted
-     * @param parentData Parent data object from which managed data object must be extracted
-     */
-    @Nonnull
-    Optional<D> extract(@Nonnull final InstanceIdentifier<D> currentId, @Nonnull final DataObject parentData);
-
-}
diff --git a/v3po/translate-spi/src/main/java/io/fd/honeycomb/v3po/translate/spi/write/ListWriterCustomizer.java b/v3po/translate-spi/src/main/java/io/fd/honeycomb/v3po/translate/spi/write/ListWriterCustomizer.java
index ecc591191..41cdb94b6 100644
--- a/v3po/translate-spi/src/main/java/io/fd/honeycomb/v3po/translate/spi/write/ListWriterCustomizer.java
+++ b/v3po/translate-spi/src/main/java/io/fd/honeycomb/v3po/translate/spi/write/ListWriterCustomizer.java
@@ -17,32 +17,18 @@
 package io.fd.honeycomb.v3po.translate.spi.write;
 
 import com.google.common.annotations.Beta;
-import com.google.common.base.Optional;
-import java.util.List;
-import javax.annotation.Nonnull;
 import org.opendaylight.yangtools.yang.binding.DataObject;
 import org.opendaylight.yangtools.yang.binding.Identifiable;
 import org.opendaylight.yangtools.yang.binding.Identifier;
-import org.opendaylight.yangtools.yang.binding.InstanceIdentifier;
 
 /**
- * CompositeListWriter SPI to customize its behavior
+ * CompositeListWriter SPI to customize its behavior.
  *
  * @param <C> Specific DataObject derived type (Identifiable), that is handled by this customizer
  * @param <K> Specific Identifier for handled type (C)
  */
 @Beta
 public interface ListWriterCustomizer<C extends DataObject & Identifiable<K>, K extends Identifier<C>> extends
-    RootWriterCustomizer<C> {
-
-    /**
-     * Get children of parentData identified by currentId
-     *
-     * @param currentId Identifier(from root) of data being extracted
-     * @param parentData Parent data object from which managed data object must be extracted
-     */
-    @Nonnull
-    Optional<List<C>> extract(@Nonnull final InstanceIdentifier<C> currentId, @Nonnull final DataObject parentData);
-    // TODO consider removing Optional and make extract return @Nullable (applies also to ChildWriterCustomizer)
+    WriterCustomizer<C> {
 
 }
\ No newline at end of file
diff --git a/v3po/translate-spi/src/main/java/io/fd/honeycomb/v3po/translate/spi/write/RootWriterCustomizer.java b/v3po/translate-spi/src/main/java/io/fd/honeycomb/v3po/translate/spi/write/WriterCustomizer.java
index 0ada8e9e5..06ce3f814 100644
--- a/v3po/translate-spi/src/main/java/io/fd/honeycomb/v3po/translate/spi/write/RootWriterCustomizer.java
+++ b/v3po/translate-spi/src/main/java/io/fd/honeycomb/v3po/translate/spi/write/WriterCustomizer.java
@@ -24,12 +24,12 @@ import org.opendaylight.yangtools.yang.binding.DataObject;
 import org.opendaylight.yangtools.yang.binding.InstanceIdentifier;
 
 /**
- * CompositeRootReader SPI to customize its behavior
+ * CompositeChildWriter SPI to customize its behavior.
  *
- * @param <D> Specific DataObject derived type, that is handled by this customizer
+ * @param <D> Specific DataObject derived type (Identifiable), that is handled by this customizer
  */
 @Beta
-public interface RootWriterCustomizer<D extends DataObject> {
+public interface WriterCustomizer<D extends DataObject> {
 
     /**
      * Handle write operation. C from CRUD.
@@ -71,4 +71,5 @@ public interface RootWriterCustomizer<D extends DataObject> {
     void deleteCurrentAttributes(@Nonnull final InstanceIdentifier<D> id,
                                  @Nonnull final D dataBefore,
                                  @Nonnull final WriteContext writeContext) throws WriteFailedException;
+
 }