Move DefaultStateRegistry to the package level.

It makes its existence more obvious. Also, removed validation of state in the `OrderAggregate`. It's too late to validate anything at the stage of applying event data. It should be done in a command handler instead.

Author: alexander-yevsyukov

examples/src/main/java/org/spine3/examples/aggregate/server/OrderAggregate.java

@@ -82,7 +82,6 @@ private void event(OrderCreated event) {
                 .setStatus(Order.Status.NEW)
                 .build();
 
-        validate(newState);
         incrementState(newState);
     }
 
@@ -96,7 +95,6 @@ private void event(OrderLineAdded event) {
                 .setTotal(currentState.getTotal() + orderLine.getTotal())
                 .build();
 
-        validate(newState);
         incrementState(newState);
     }
 
@@ -108,7 +106,6 @@ private void event(OrderPaid event) {
                 .setStatus(Order.Status.PAID)
                 .build();
 
-        validate(newState);
         incrementState(newState);
     }
 

server/src/main/java/org/spine3/server/entity/DefaultStateRegistry.java

@@ -0,0 +1,85 @@
+/*
+ * Copyright 2016, TeamDev Ltd. All rights reserved.
+ *
+ * Redistribution and use in source and/or binary forms, with or without
+ * modification, must retain the above copyright notice and the following
+ * disclaimer.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+package org.spine3.server.entity;
+
+import com.google.protobuf.Message;
+
+import javax.annotation.CheckReturnValue;
+import java.util.Map;
+
+import static com.google.common.collect.Maps.newHashMap;
+
+/**
+ * A wrapper for the map from entity classes to entity default states.
+ *
+ * @author Alexander Yevsyukov
+ */
+/* package */ class DefaultStateRegistry {
+
+    private final Map<Class<? extends Entity>, Message> defaultStates = newHashMap();
+
+    /**
+     * Specifies if the entity state of this class is already registered.
+     *
+     * @param entityClass the class to check
+     * @return {@code true} if there is a state for the passed class, {@code false} otherwise
+     */
+    @CheckReturnValue
+    /* package */ boolean contains(Class<? extends Entity> entityClass) {
+        final boolean result = defaultStates.containsKey(entityClass);
+        return result;
+    }
+
+    /**
+     * Saves a state.
+     *
+     * @param entityClass an entity class
+     * @param state a default state of the entity
+     * @throws IllegalArgumentException if the state of this class is already registered
+     */
+    /* package */ void put(Class<? extends Entity> entityClass, Message state) {
+        if (contains(entityClass)) {
+            throw new IllegalArgumentException("This class is registered already: " + entityClass.getName());
+        }
+        defaultStates.put(entityClass, state);
+    }
+
+    /**
+     * Obtains a state for the passed class..
+     *
+     * @param entityClass an entity class
+     */
+    @CheckReturnValue
+    /* package */ Message get(Class<? extends Entity> entityClass) {
+        final Message state = defaultStates.get(entityClass);
+        return state;
+    }
+
+    /* package */ static DefaultStateRegistry getInstance() {
+        return Singleton.INSTANCE.value;
+    }
+
+    private enum Singleton {
+        INSTANCE;
+        @SuppressWarnings("NonSerializableFieldInSerializableClass")
+        private final DefaultStateRegistry value = new DefaultStateRegistry();
+    }
+}

server/src/main/java/org/spine3/server/entity/Entity.java

@@ -32,12 +32,10 @@
 import javax.annotation.Nonnull;
 import java.lang.reflect.Constructor;
 import java.lang.reflect.InvocationTargetException;
-import java.util.Map;
 
 import static com.google.api.client.util.Throwables.propagate;
 import static com.google.common.base.Preconditions.checkNotNull;
 import static com.google.common.collect.Iterables.transform;
-import static com.google.common.collect.Maps.newHashMap;
 import static com.google.protobuf.util.TimeUtil.getCurrentTime;
 
 /**
@@ -120,15 +118,15 @@ protected S getDefaultState() {
         final Class<? extends Entity> entityClass = getClass();
         final DefaultStateRegistry registry = DefaultStateRegistry.getInstance();
         if (!registry.contains(entityClass)) {
-            final S state = retrieveDefaultState();
+            final S state = createDefaultState();
             registry.put(entityClass, state);
         }
         @SuppressWarnings("unchecked") // cast is safe because this type of messages is saved to the map
         final S defaultState = (S) registry.get(entityClass);
         return defaultState;
     }
 
-    private S retrieveDefaultState() {
+    private S createDefaultState() {
         final Class<S> stateClass = Classes.getGenericParameterType(getClass(), STATE_CLASS_GENERIC_INDEX);
         try {
             final Constructor<S> constructor = stateClass.getDeclaredConstructor();
@@ -154,8 +152,8 @@ public S getState() {
     /**
      * Validates the passed state.
      *
-     * <p>Does nothing by default. Aggregate roots may override this method to
-     * specify logic of validating initial or intermediate state of the root.
+     * <p>Does nothing by default. Aggregates may override this method to
+     * specify logic of validating initial or intermediate state.
      *
      * @param state a state object to replace the current state
      * @throws IllegalStateException if the state is not valid
@@ -307,58 +305,4 @@ public String apply(Class<?> clazz) {
         return result;
     }
 
-    /**
-     * A wrapper for the map from entity classes to entity default states.
-     */
-    private static class DefaultStateRegistry {
-
-        private final Map<Class<? extends Entity>, Message> defaultStates = newHashMap();
-
-        /**
-         * Specifies if the entity state of this class is already registered.
-         *
-         * @param entityClass the class to check
-         * @return {@code true} if there is a state for the passed class, {@code false} otherwise
-         */
-        @CheckReturnValue
-        private boolean contains(Class<? extends Entity> entityClass) {
-            final boolean result = defaultStates.containsKey(entityClass);
-            return result;
-        }
-
-        /**
-         * Saves a state.
-         *
-         * @param entityClass an entity class
-         * @param state a default state of the entity
-         * @throws IllegalArgumentException if the state of this class is already registered
-         */
-        private void put(Class<? extends Entity> entityClass, Message state) {
-            if (contains(entityClass)) {
-                throw new IllegalArgumentException("This class is registered already: " + entityClass.getName());
-            }
-            defaultStates.put(entityClass, state);
-        }
-
-        /**
-         * Obtains a state for the passed class..
-         *
-         * @param entityClass an entity class
-         */
-        @CheckReturnValue
-        private Message get(Class<? extends Entity> entityClass) {
-            final Message state = defaultStates.get(entityClass);
-            return state;
-        }
-
-        private static DefaultStateRegistry getInstance() {
-            return Singleton.INSTANCE.value;
-        }
-
-        private enum Singleton {
-            INSTANCE;
-            @SuppressWarnings("NonSerializableFieldInSerializableClass")
-            private final DefaultStateRegistry value = new DefaultStateRegistry();
-        }
-    }
 }