feat: Add interfaces for CRUD services

These were previously in Hilla but are equally useful in Flow applications

flow-server/src/main/java/com/vaadin/flow/Nonnull.java

@@ -0,0 +1,36 @@
+/*
+ * Copyright 2000-2022 Vaadin Ltd.
+ *
+ * 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.vaadin.flow;
+
+import java.lang.annotation.Documented;
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+/**
+ * Annotation to mark either field, method, parameter or type parameter as
+ * non-nullable. It is used by Typescript Generator as a source of type
+ * nullability information.
+ *
+ * This annotation exists because the traditional
+ * `jakarta.annotation.Nonnull` annotation is not applicable to type parameters.
+ */
+@Documented
+@Retention(RetentionPolicy.RUNTIME)
+@Target({ ElementType.TYPE_USE })
+public @interface Nonnull {
+}

flow-server/src/main/java/com/vaadin/flow/Nullable.java

@@ -0,0 +1,37 @@
+/*
+ * Copyright 2000-2022 Vaadin Ltd.
+ *
+ * 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.vaadin.flow;
+
+import java.lang.annotation.Documented;
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+/**
+ * Annotation to mark either field, method, parameter or type parameter as
+ * nullable. It is used by Typescript Generator as a source of type nullability
+ * information.
+ *
+ * This annotation exists because the traditional
+ * `jakarta.annotation.Nullable` annotation is not applicable to type
+ * parameters.
+ */
+@Documented
+@Retention(RetentionPolicy.RUNTIME)
+@Target({ ElementType.TYPE_USE })
+public @interface Nullable {
+}

vaadin-spring/pom.xml

@@ -97,6 +97,26 @@
             <artifactId>spring-data-commons</artifactId>
             <optional>true</optional>
         </dependency>
+        <dependency>
+            <groupId>org.springframework.data</groupId>
+            <artifactId>spring-data-jpa</artifactId>
+            <scope>provided</scope>
+            <exclusions>
+                <exclusion>
+                    <artifactId>aspectjrt</artifactId>
+                    <groupId>org.aspectj</groupId>
+                </exclusion>
+                <exclusion>
+                    <artifactId>jcl-over-slf4j</artifactId>
+                    <groupId>org.slf4j</groupId>
+                </exclusion>
+            </exclusions>
+        </dependency>
+        <dependency>
+            <groupId>jakarta.persistence</groupId>
+            <artifactId>jakarta.persistence-api</artifactId>
+            <scope>provided</scope>
+        </dependency>
         <dependency>
             <groupId>com.vaadin</groupId>
             <artifactId>flow-data</artifactId>

vaadin-spring/src/main/java/com/vaadin/flow/spring/data/CountService.java

@@ -0,0 +1,22 @@
+package com.vaadin.flow.spring.data;
+
+import org.springframework.lang.Nullable;
+
+import com.vaadin.flow.spring.data.filter.Filter;
+
+/**
+ * A browser-callable service that can count the given type of objects with a
+ * given filter.
+ */
+public interface CountService {
+
+    /**
+     * Counts the number of entities that match the given filter.
+     *
+     * @param filter
+     *            the filter, or {@code null} to use no filter
+     * @return
+     */
+    public long count(@Nullable Filter filter);
+
+}

vaadin-spring/src/main/java/com/vaadin/flow/spring/data/CrudService.java

@@ -0,0 +1,8 @@
+package com.vaadin.flow.spring.data;
+
+/**
+ * A browser-callable service that can create, read, update, and delete a given
+ * type of object.
+ */
+public interface CrudService<T, ID> extends ListService<T>, FormService<T, ID> {
+}

vaadin-spring/src/main/java/com/vaadin/flow/spring/data/FormService.java

@@ -0,0 +1,31 @@
+package com.vaadin.flow.spring.data;
+
+import org.springframework.lang.Nullable;
+
+/**
+ * A browser-callable service that can create, update, and delete a given type
+ * of object.
+ */
+public interface FormService<T, ID> {
+
+    /**
+     * Saves the given object and returns the (potentially) updated object.
+     * <p>
+     * If you store the object in a SQL database, the returned object might have
+     * a new id or updated consistency version.
+     *
+     * @param value
+     *            the object to save
+     * @return the fresh object or {@code null} if no object was found to update
+     */
+    @Nullable
+    T save(T value);
+
+    /**
+     * Deletes the object with the given id.
+     *
+     * @param id
+     *            the id of the object to delete
+     */
+    void delete(ID id);
+}

vaadin-spring/src/main/java/com/vaadin/flow/spring/data/GetService.java

@@ -0,0 +1,30 @@
+package com.vaadin.flow.spring.data;
+
+import java.util.Optional;
+
+/**
+ * A browser-callable service that can fetch the given type of object.
+ */
+public interface GetService<T, ID> {
+
+    /**
+     * Gets the object with the given id.
+     *
+     * @param id
+     *            the id of the object
+     * @return the object, or an empty optional if no object with the given id
+     */
+    Optional<T> get(ID id);
+
+    /**
+     * Checks if an object with the given id exists.
+     *
+     * @param id
+     *            the id of the object
+     * @return {@code true} if the object exists, {@code false} otherwise
+     */
+    default boolean exists(ID id) {
+        return get(id).isPresent();
+    }
+
+}

vaadin-spring/src/main/java/com/vaadin/flow/spring/data/ListService.java

@@ -0,0 +1,28 @@
+package com.vaadin.flow.spring.data;
+
+import java.util.List;
+
+import com.vaadin.flow.Nullable;
+import com.vaadin.flow.Nonnull;
+
+import com.vaadin.flow.spring.data.filter.Filter;
+import org.springframework.data.domain.Pageable;
+
+/**
+ * A browser-callable service that can list the given type of object.
+ */
+public interface ListService<T> {
+    /**
+     * Lists objects of the given type using the paging, sorting and filtering
+     * options provided in the parameters.
+     *
+     * @param pageable
+     *            contains information about paging and sorting
+     * @param filter
+     *            the filter to apply or {@code null} to not filter
+     * @return a list of objects or an empty list if no objects were found
+     */
+    @Nonnull
+    List<@Nonnull T> list(Pageable pageable, @Nullable Filter filter);
+
+}