Common classes for JSON based REST APIs for integration. (helidon-io#…

…2879)

* Common classes for JSON based REST APIs for integration.

bom/pom.xml

@@ -844,6 +844,11 @@
                 <artifactId>helidon-mp-graal-native-image-extension</artifactId>
                 <version>${helidon.version}</version>
             </dependency>
+            <dependency>
+                <groupId>io.helidon.integrations.common</groupId>
+                <artifactId>helidon-integrations-common-rest</artifactId>
+                <version>${helidon.version}</version>
+            </dependency>
             <!-- OpenAPI support -->
             <dependency>
                 <groupId>io.helidon.openapi</groupId>

integrations/common/pom.xml

@@ -0,0 +1,38 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--
+  ~ Copyright (c) 2021 Oracle 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.
+  -->
+
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+        xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <parent>
+        <groupId>io.helidon.integrations</groupId>
+        <artifactId>helidon-integrations-project</artifactId>
+        <version>2.3.0-SNAPSHOT</version>
+    </parent>
+
+    <packaging>pom</packaging>
+    <groupId>io.helidon.integrations.common</groupId>
+    <artifactId>helidon-integrations-common-project</artifactId>
+    <name>Helidon Integrations Common Project</name>
+
+    <description>Common classes for integration modules</description>
+
+    <modules>
+        <module>rest</module>
+    </modules>
+</project>

integrations/common/rest/pom.xml

@@ -0,0 +1,75 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--
+  ~ Copyright (c) 2021 Oracle 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.
+  -->
+
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+        xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <parent>
+        <groupId>io.helidon.integrations.common</groupId>
+        <artifactId>helidon-integrations-common-project</artifactId>
+        <version>2.3.0-SNAPSHOT</version>
+    </parent>
+
+    <artifactId>helidon-integrations-common-rest</artifactId>
+    <name>Helidon Integrations Common REST</name>
+
+    <description>Common classes for integrating third party systems over REST API with JSON</description>
+
+    <dependencies>
+        <dependency>
+            <groupId>io.helidon.common</groupId>
+            <artifactId>helidon-common-http</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>io.helidon.config</groupId>
+            <artifactId>helidon-config</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>io.helidon.webclient</groupId>
+            <artifactId>helidon-webclient</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>io.helidon.media</groupId>
+            <artifactId>helidon-media-jsonp</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>io.helidon.fault-tolerance</groupId>
+            <artifactId>helidon-fault-tolerance</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>io.opentracing</groupId>
+            <artifactId>opentracing-api</artifactId>
+        </dependency>
+
+        <dependency>
+            <groupId>org.junit.jupiter</groupId>
+            <artifactId>junit-jupiter-api</artifactId>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.hamcrest</groupId>
+            <artifactId>hamcrest-all</artifactId>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>io.helidon.webserver</groupId>
+            <artifactId>helidon-webserver</artifactId>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+</project>

integrations/common/rest/src/main/java/io/helidon/integrations/common/rest/ApiEntityResponse.java

@@ -0,0 +1,73 @@
+/*
+ * Copyright (c) 2021 Oracle 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.helidon.integrations.common.rest;
+
+/**
+ * Response from a remote server with an entity.
+ */
+public abstract class ApiEntityResponse extends ApiResponse {
+    /**
+     * Create a new instance.
+     *
+     * @param builder the builder
+     */
+    protected ApiEntityResponse(Builder<?, ?, ?> builder) {
+        super(builder);
+    }
+
+    /**
+     * Fluent API builder base to build subclasses of {@link io.helidon.integrations.common.rest.ApiEntityResponse}.
+     *
+     * @param <B> type of the builder (subclass of this class)
+     * @param <T> type of the response being built
+     * @param <X> type of the entity supported ({@link javax.json.JsonObject}, {@link io.helidon.common.reactive.Multi}, or
+     *           {@code byte[]})
+     */
+    public abstract static class Builder<B extends Builder<B, T, X>, T extends ApiEntityResponse, X>
+            extends ApiResponse.Builder<B, T>
+            implements ResponseBuilder<B, T, X> {
+        private X entity;
+
+        /**
+         * Create a new builder instance.
+         */
+        protected Builder() {
+        }
+
+        /**
+         * This method is invoked by {@link io.helidon.integrations.common.rest.RestApi} when an entity
+         * is received.
+         *
+         * @param entity entity
+         * @return updated builder
+         */
+        public B entity(X entity) {
+            this.entity = entity;
+            return me();
+        }
+
+        /**
+         * Accessor to entity that can be used in subclasses of {@link io.helidon.integrations.common.rest.ApiEntityResponse}
+         *  to set up fields.
+         *
+         * @return received entity
+         */
+        public X entity() {
+            return entity;
+        }
+    }
+}

integrations/common/rest/src/main/java/io/helidon/integrations/common/rest/ApiException.java

@@ -0,0 +1,57 @@
+/*
+ * Copyright (c) 2021 Oracle 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.helidon.integrations.common.rest;
+
+/**
+ * API exception that is not related to processing of a response.
+ *
+ * @see io.helidon.integrations.common.rest.RestException
+ */
+public class ApiException extends RuntimeException {
+    /**
+     * New exception without a cause and message.
+     */
+    public ApiException() {
+    }
+
+    /**
+     * New exception with a message and without a cause.
+     * @param message message to use
+     */
+    public ApiException(String message) {
+        super(message);
+    }
+
+    /**
+     * New exception with a cause and message.
+     *
+     * @param message message to use
+     * @param cause throwable that caused this exception
+     */
+    public ApiException(String message, Throwable cause) {
+        super(message, cause);
+    }
+
+    /**
+     * New exception with a cause and without a message.
+     *
+     * @param cause throwable that caused this exception
+     */
+    public ApiException(Throwable cause) {
+        super(cause);
+    }
+}