Move Request and Response to loadbalancer package. Fixes gh-772. (#773)

* Move Request and Response to loadbalancer package. Fixes gh-772.

* Fix checkstyle.

* Inherit and reference repackaged classes.

* Revert "Inherit and reference repackaged classes."

This reverts commit 02808c5.

* Fix Status enums.

* Make old classes extend the new ones.

Author: OlgaMaciaszek

spring-cloud-commons/src/main/java/org/springframework/cloud/client/loadbalancer/CompletionContext.java

@@ -0,0 +1,70 @@
+/*
+ * Copyright 2012-2020 the original author or authors.
+ *
+ * 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
+ *
+ *      https://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 org.springframework.cloud.client.loadbalancer;
+
+import org.springframework.core.style.ToStringCreator;
+
+/**
+ * @author Spencer Gibb
+ */
+// TODO: add metrics
+public class CompletionContext {
+
+	private final Status status;
+
+	private final Throwable throwable;
+
+	public CompletionContext(Status status) {
+		this(status, null);
+	}
+
+	public CompletionContext(Status status, Throwable throwable) {
+		this.status = status;
+		this.throwable = throwable;
+	}
+
+	public Status status() {
+		return this.status;
+	}
+
+	public Throwable getThrowable() {
+		return this.throwable;
+	}
+
+	@Override
+	public String toString() {
+		ToStringCreator to = new ToStringCreator(this);
+		to.append("status", this.status);
+		to.append("throwable", this.throwable);
+		return to.toString();
+	}
+
+	/**
+	 * Request status state.
+	 */
+	public enum Status {
+
+		/** Request was handled successfully. */
+		SUCCESS,
+		/** Request reached the server but failed due to timeout or internal error. */
+		FAILED,
+		/** Request did not go off box and should not be counted for statistics. */
+		DISCARD,
+
+	}
+
+}

spring-cloud-commons/src/main/java/org/springframework/cloud/client/loadbalancer/DefaultRequest.java

@@ -0,0 +1,46 @@
+/*
+ * Copyright 2012-2020 the original author or authors.
+ *
+ * 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
+ *
+ *      https://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 org.springframework.cloud.client.loadbalancer;
+
+/**
+ * A default implementation of {@link Request}.
+ *
+ * @author Spencer Gibb
+ * @author Olga Maciaszek-Sharma
+ */
+public class DefaultRequest<T> implements Request<T> {
+
+	private T context;
+
+	public DefaultRequest() {
+		new DefaultRequestContext();
+	}
+
+	public DefaultRequest(T context) {
+		this.context = context;
+	}
+
+	@Override
+	public T getContext() {
+		return context;
+	}
+
+	public void setContext(T context) {
+		this.context = context;
+	}
+
+}

spring-cloud-commons/src/main/java/org/springframework/cloud/client/loadbalancer/DefaultRequestContext.java

@@ -0,0 +1,47 @@
+/*
+ * Copyright 2012-2020 the original author or authors.
+ *
+ * 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
+ *
+ *      https://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 org.springframework.cloud.client.loadbalancer;
+
+/**
+ * Contains information relevant to the request.
+ *
+ * @author Olga Maciaszek-Sharma
+ */
+public class DefaultRequestContext {
+
+	/**
+	 * A {@link String} value of hint that can be used to choose the correct service
+	 * instance.
+	 */
+	private String hint = "default";
+
+	public DefaultRequestContext() {
+	}
+
+	public DefaultRequestContext(String hint) {
+		this.hint = hint;
+	}
+
+	public String getHint() {
+		return hint;
+	}
+
+	public void setHint(String hint) {
+		this.hint = hint;
+	}
+
+}

spring-cloud-commons/src/main/java/org/springframework/cloud/client/loadbalancer/DefaultResponse.java

@@ -0,0 +1,47 @@
+/*
+ * Copyright 2012-2020 the original author or authors.
+ *
+ * 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
+ *
+ *      https://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 org.springframework.cloud.client.loadbalancer;
+
+import org.springframework.cloud.client.ServiceInstance;
+
+/**
+ * @author Spencer Gibb
+ */
+public class DefaultResponse implements Response<ServiceInstance> {
+
+	private final ServiceInstance serviceInstance;
+
+	public DefaultResponse(ServiceInstance serviceInstance) {
+		this.serviceInstance = serviceInstance;
+	}
+
+	@Override
+	public boolean hasServer() {
+		return this.serviceInstance != null;
+	}
+
+	@Override
+	public ServiceInstance getServer() {
+		return this.serviceInstance;
+	}
+
+	@Override
+	public void onComplete(CompletionContext completionContext) {
+		// TODO: implement
+	}
+
+}

spring-cloud-commons/src/main/java/org/springframework/cloud/client/loadbalancer/EmptyResponse.java

@@ -0,0 +1,41 @@
+/*
+ * Copyright 2012-2020 the original author or authors.
+ *
+ * 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
+ *
+ *      https://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 org.springframework.cloud.client.loadbalancer;
+
+import org.springframework.cloud.client.ServiceInstance;
+
+/**
+ * @author Spencer Gibb
+ */
+public class EmptyResponse implements Response<ServiceInstance> {
+
+	@Override
+	public boolean hasServer() {
+		return false;
+	}
+
+	@Override
+	public ServiceInstance getServer() {
+		return null;
+	}
+
+	@Override
+	public void onComplete(CompletionContext completionContext) {
+		// TODO: implement
+	}
+
+}

spring-cloud-commons/src/main/java/org/springframework/cloud/client/loadbalancer/Request.java

@@ -0,0 +1,34 @@
+/*
+ * Copyright 2012-2020 the original author or authors.
+ *
+ * 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
+ *
+ *      https://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 org.springframework.cloud.client.loadbalancer;
+
+/**
+ * Marker interface for a request.
+ *
+ * @author Spencer Gibb
+ * @author Olga Maciaszek-Sharma
+ */
+public interface Request<C> {
+
+	// Avoid breaking backward compatibility
+	default C getContext() {
+		return null;
+	}
+
+	// TODO: define contents
+
+}

spring-cloud-commons/src/main/java/org/springframework/cloud/client/loadbalancer/Response.java

@@ -0,0 +1,40 @@
+/*
+ * Copyright 2012-2020 the original author or authors.
+ *
+ * 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
+ *
+ *      https://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 org.springframework.cloud.client.loadbalancer;
+
+/**
+ * Response created for each request.
+ *
+ * @param <T> type of the server
+ * @author Spencer Gibb
+ */
+public interface Response<T> {
+
+	boolean hasServer();
+
+	T getServer();
+
+	/**
+	 * Notification that the request completed.
+	 * @deprecated <code>onComplete</code> callbacks for load-balanced calls are being
+	 * moved to a separate interface
+	 * @param completionContext - completion context
+	 */
+	@Deprecated
+	void onComplete(CompletionContext completionContext);
+
+}

spring-cloud-commons/src/main/java/org/springframework/cloud/client/loadbalancer/reactive/CompletionContext.java

@@ -16,46 +16,46 @@
 
 package org.springframework.cloud.client.loadbalancer.reactive;
 
-import org.springframework.core.style.ToStringCreator;
-
 /**
+ * @deprecated in favour of
+ * {@link org.springframework.cloud.client.loadbalancer.CompletionContext}
  * @author Spencer Gibb
  */
 // TODO: add metrics
-public class CompletionContext {
+@Deprecated
+public class CompletionContext
+		extends org.springframework.cloud.client.loadbalancer.CompletionContext {
 
 	private final Status status;
 
-	private final Throwable throwable;
-
 	public CompletionContext(Status status) {
 		this(status, null);
 	}
 
 	public CompletionContext(Status status, Throwable throwable) {
+		super(resolveStatus(status), throwable);
 		this.status = status;
-		this.throwable = throwable;
 	}
 
 	public Status getStatus() {
 		return this.status;
 	}
 
-	public Throwable getThrowable() {
-		return this.throwable;
-	}
-
-	@Override
-	public String toString() {
-		ToStringCreator to = new ToStringCreator(this);
-		to.append("status", this.status);
-		to.append("throwable", this.throwable);
-		return to.toString();
+	private static org.springframework.cloud.client.loadbalancer.CompletionContext.Status resolveStatus(
+			Status status) {
+		if (Status.SUCCESSS.equals(status)) {
+			return org.springframework.cloud.client.loadbalancer.CompletionContext.Status.SUCCESS;
+		}
+		return org.springframework.cloud.client.loadbalancer.CompletionContext.Status
+				.valueOf(status.name());
 	}
 
 	/**
 	 * Request status state.
+	 * @deprecated in favour of
+	 * {@link org.springframework.cloud.client.loadbalancer.CompletionContext.Status}
 	 */
+	@Deprecated
 	public enum Status {
 
 		/** Request was handled successfully. */