Runtime: Change API for backward streaming

runtime/dependency-reduced-pom.xml

@@ -23,7 +23,6 @@
                             com.speedment.runtime.component.*,
                             com.speedment.runtime.config.*,
                             com.speedment.runtime.db.*,
-                            com.speedment.runtime.entity.*,
                             com.speedment.runtime.exception.*,
                             com.speedment.runtime.field.*,
                             com.speedment.runtime.license.*,

runtime/src/main/java/com/speedment/runtime/field/method/BackwardFinder.java

@@ -0,0 +1,65 @@
+/*
+ * Copyright (c) Emil Forslund, 2016.
+ * All Rights Reserved.
+ * 
+ * NOTICE:  All information contained herein is, and remains
+ * the property of Emil Forslund and his suppliers, if any. 
+ * The intellectual and technical concepts contained herein 
+ * are proprietary to Emil Forslund and his suppliers and may 
+ * be covered by U.S. and Foreign Patents, patents in process, 
+ * and are protected by trade secret or copyright law. 
+ * Dissemination of this information or reproduction of this 
+ * material is strictly forbidden unless prior written 
+ * permission is obtained from Emil Forslund himself.
+ */
+package com.speedment.runtime.field.method;
+
+import com.speedment.runtime.field.trait.HasFinder;
+import com.speedment.runtime.manager.Manager;
+import java.util.function.Function;
+import java.util.stream.Stream;
+
+/**
+ * An operation that can produce a {@code Stream} of foreign entities given a
+ * single entity. This is useful since it can be passed to an outer stream as
+ * the argument for a {@code flatMap()}-operation.
+ * <p>
+ * Each streamer contains metadata of which fields it compares to determine the
+ * mapping as well as a reference to the foreign manager.
+ * <p>
+ * Streamers have the following signature:
+ * {@code
+ *      Stream<FK_ENTITY> apply(ENTITY entity);
+ * }
+ * 
+ * @param <ENTITY>     the source entity
+ * @param <FK_ENTITY>  the target entity
+ * @param <V>          the wrapper type
+ * 
+ * @author  Emil Forslund
+ * @since   3.0.1
+ */
+public interface BackwardFinder<ENTITY, FK_ENTITY, V> 
+    extends Function<ENTITY, Stream<FK_ENTITY>> {
+
+    /**
+     * Returns the field that the stream references. 
+     * <p>
+     * In the following example, {@code bar} is the target:
+     * {@code
+     *      foos.stream()
+     *          .flatMap(foo.findBars()) // findBars returns Streamer<Foo, Bar>
+     *          .forEach(...);
+     * }
+     * 
+     * @return  the target field
+     */
+    HasFinder<FK_ENTITY, ENTITY, V> getField();
+
+    /**
+     * Returns the manager used for the referenced (foreign) table.
+     * 
+     * @return  target (foreign) manager
+     */
+    Manager<FK_ENTITY> getTargetManager();
+}

runtime/src/main/java/com/speedment/runtime/field/method/FindFrom.java

@@ -0,0 +1,77 @@
+/**
+ *
+ * Copyright (c) 2006-2016, Speedment, Inc. 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. 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 com.speedment.runtime.field.method;
+
+import com.speedment.runtime.field.Field;
+import com.speedment.runtime.manager.Manager;
+import java.util.function.Function;
+
+/**
+ * A handle for a find-operation that can be replaced runtime to optimize a 
+ * {@code Stream}. Formally, a {@code FindFrom} has the following signature:
+ * {@code
+ *      FK_ENTITY apply(ENTITY entity);
+ * }
+ * <p>
+ * Each {@code FindFrom} contains metadata of which fields it compares to 
+ * determine the mapping as well as a reference to the foreign manager.
+ * 
+ * @param <ENTITY>     the source entity
+ * @param <FK_ENTITY>  the target entity
+ * @param <V>          the wrapper type
+ * 
+ * @author Emil Forslund
+ * @since  3.0.0
+ */
+public interface FindFrom<ENTITY, FK_ENTITY, V> extends Function<ENTITY, FK_ENTITY> {
+
+    /**
+     * Returns the field that the stream originates from. 
+     * <p>
+     * In the following example, {@code foo} is the source:
+     * {@code
+     *      foos.stream()
+     *          .flatMap(foo.findBars()) // findBars returns Streamer<Foo, Bar>
+     *          .forEach(...);
+     * }
+     * 
+     * @return  the source field
+     */
+    Field<ENTITY, V> getSourceField();
+
+    /**
+     * Returns the field that the stream references. 
+     * <p>
+     * In the following example, {@code bar} is the target:
+     * {@code
+     *      foos.stream()
+     *          .flatMap(foo.findBars()) // findBars returns Streamer<Foo, Bar>
+     *          .forEach(...);
+     * }
+     * 
+     * @return  the target field
+     */
+    Field<FK_ENTITY, V> getTargetField();
+
+    /**
+     * Returns the manager used for the referenced (foreign) table.
+     * 
+     * @return  target (foreign) manager
+     */
+    Manager<FK_ENTITY> getTargetManager();
+
+}

runtime/src/main/java/com/speedment/runtime/field/trait/HasFinder.java

@@ -17,9 +17,10 @@
 package com.speedment.runtime.field.trait;
 
 import com.speedment.runtime.annotation.Api;
-import com.speedment.runtime.field.finder.FindFrom;
+import com.speedment.runtime.field.Field;
+import com.speedment.runtime.field.method.FindFrom;
 import com.speedment.runtime.manager.Manager;
-import com.speedment.runtime.field.method.Finder;
+import com.speedment.runtime.field.method.BackwardFinder;
 
 /**
  * A representation of an Entity field that use a foreign key to 
@@ -35,14 +36,13 @@
  */
 @Api(version = "3.0")
 public interface HasFinder<ENTITY, FK_ENTITY, V> {
-
+    
     /**
-     * Returns a function that can find a foreign entity pointed out by this
-     * field.
-     *
-     * @return the finder
+     * Returns the field referenced by this finder.
+     * 
+     * @return  the referenced field
      */
-    Finder<ENTITY, FK_ENTITY> finder();
+    Field<FK_ENTITY, V> getReferencedField();
 
     /**
      * Returns a function that can be used to find referenced entites using the
@@ -51,16 +51,14 @@ public interface HasFinder<ENTITY, FK_ENTITY, V> {
      * @param foreignManager  the foreign manager
      * @return                finder method
      */
-    FindFrom<ENTITY, FK_ENTITY, V> findFrom(Manager<FK_ENTITY> foreignManager);
-
+    FindFrom<ENTITY, FK_ENTITY, V> finder(Manager<FK_ENTITY> foreignManager);
+    
     /**
-     * Finds the foreign entity associated by this field.
-     *
-     * @param entity          this entity
-     * @param foreignManager  the foreign manager
-     * @return                the foreign entity associated by this field
+     * Returns a function that can be used to find a stream of entities 
+     * referencing this entity using the specified manager.
+     * 
+     * @param manager  the foreign manager
+     * @return                streaming method
      */
-    default FK_ENTITY findFrom(ENTITY entity, Manager<FK_ENTITY> foreignManager) {
-        return finder().apply(entity, foreignManager);
-    }
+    BackwardFinder<FK_ENTITY, ENTITY, V> backwardFinder(Manager<ENTITY> manager);
 }

runtime/src/main/java/com/speedment/runtime/internal/field/ByteForeignKeyFieldImpl.java

@@ -4,9 +4,10 @@
 import com.speedment.runtime.config.mapper.TypeMapper;
 import com.speedment.runtime.field.ByteField;
 import com.speedment.runtime.field.ByteForeignKeyField;
-import com.speedment.runtime.field.finder.FindFrom;
+import com.speedment.runtime.field.method.BackwardFinder;
 import com.speedment.runtime.field.method.ByteGetter;
 import com.speedment.runtime.field.method.ByteSetter;
+import com.speedment.runtime.field.method.FindFrom;
 import com.speedment.runtime.field.method.Finder;
 import com.speedment.runtime.field.predicate.FieldPredicate;
 import com.speedment.runtime.field.predicate.Inclusion;
@@ -18,6 +19,7 @@
 import com.speedment.runtime.internal.field.predicate.bytes.ByteGreaterOrEqualPredicate;
 import com.speedment.runtime.internal.field.predicate.bytes.ByteGreaterThanPredicate;
 import com.speedment.runtime.internal.field.predicate.bytes.ByteInPredicate;
+import com.speedment.runtime.internal.field.streamer.BackwardFinderImpl;
 import com.speedment.runtime.manager.Manager;
 import java.util.Set;
 import java.util.function.Predicate;
@@ -67,13 +69,18 @@ public ByteGetter<ENTITY> getter() {
     }
 
     @Override
-    public FindFrom<ENTITY, FK_ENTITY, Byte> findFrom(Manager<FK_ENTITY> foreignManager) {
-        return new FindFromByte<>(this, referenced, foreignManager);
+    public ByteField<FK_ENTITY, ?> getReferencedField() {
+        return referenced;
     }
 
     @Override
-    public Finder<ENTITY, FK_ENTITY> finder() {
-        return finder;
+    public BackwardFinder<FK_ENTITY, ENTITY, Byte> backwardFinder(Manager<ENTITY> manager) {
+        return new BackwardFinderImpl<>(this, manager);
+    }
+
+    @Override
+    public FindFrom<ENTITY, FK_ENTITY, Byte> finder(Manager<FK_ENTITY> foreignManager) {
+        return new FindFromByte<>(this, referenced, foreignManager);
     }
 
     @Override

runtime/src/main/java/com/speedment/runtime/internal/field/CharForeignKeyFieldImpl.java

@@ -4,9 +4,10 @@
 import com.speedment.runtime.config.mapper.TypeMapper;
 import com.speedment.runtime.field.CharField;
 import com.speedment.runtime.field.CharForeignKeyField;
-import com.speedment.runtime.field.finder.FindFrom;
+import com.speedment.runtime.field.method.BackwardFinder;
 import com.speedment.runtime.field.method.CharGetter;
 import com.speedment.runtime.field.method.CharSetter;
+import com.speedment.runtime.field.method.FindFrom;
 import com.speedment.runtime.field.method.Finder;
 import com.speedment.runtime.field.predicate.FieldPredicate;
 import com.speedment.runtime.field.predicate.Inclusion;
@@ -18,6 +19,7 @@
 import com.speedment.runtime.internal.field.predicate.chars.CharGreaterOrEqualPredicate;
 import com.speedment.runtime.internal.field.predicate.chars.CharGreaterThanPredicate;
 import com.speedment.runtime.internal.field.predicate.chars.CharInPredicate;
+import com.speedment.runtime.internal.field.streamer.BackwardFinderImpl;
 import com.speedment.runtime.manager.Manager;
 import java.util.Set;
 import java.util.function.Predicate;
@@ -67,13 +69,18 @@ public CharGetter<ENTITY> getter() {
     }
 
     @Override
-    public FindFrom<ENTITY, FK_ENTITY, Character> findFrom(Manager<FK_ENTITY> foreignManager) {
-        return new FindFromChar<>(this, referenced, foreignManager);
+    public CharField<FK_ENTITY, ?> getReferencedField() {
+        return referenced;
     }
 
     @Override
-    public Finder<ENTITY, FK_ENTITY> finder() {
-        return finder;
+    public BackwardFinder<FK_ENTITY, ENTITY, Character> backwardFinder(Manager<ENTITY> manager) {
+        return new BackwardFinderImpl<>(this, manager);
+    }
+
+    @Override
+    public FindFrom<ENTITY, FK_ENTITY, Character> finder(Manager<FK_ENTITY> foreignManager) {
+        return new FindFromChar<>(this, referenced, foreignManager);
     }
 
     @Override