refactor: extract common config functionality and introduce add config

flow-server/src/main/java/com/vaadin/flow/function/DeploymentConfiguration.java

@@ -23,14 +23,14 @@
 import java.util.function.Function;
 import java.util.stream.Collectors;
 
+import com.vaadin.flow.server.AbstractConfiguration;
 import com.vaadin.flow.server.Constants;
 import com.vaadin.flow.server.InitParameters;
 import com.vaadin.flow.server.WrappedSession;
 import com.vaadin.flow.shared.communication.PushMode;
 
 import static com.vaadin.flow.server.Constants.POLYFILLS_DEFAULT_VALUE;
 import static com.vaadin.flow.server.InitParameters.SERVLET_PARAMETER_POLYFILLS;
-import static com.vaadin.flow.server.InitParameters.SERVLET_PARAMETER_USE_V14_BOOTSTRAP;
 
 /**
  * A collection of properties configured at deploy time as well as a way of
@@ -39,23 +39,8 @@
  * @author Vaadin Ltd
  * @since 1.0
  */
-public interface DeploymentConfiguration extends Serializable {
-
-    /**
-     * Returns whether Vaadin is in production mode.
-     *
-     * @return true if in production mode, false otherwise.
-     */
-    boolean isProductionMode();
-
-    /**
-     * Returns whether Vaadin is running in useDeprecatedV14Bootstrapping.
-     *
-     * @return true if in useDeprecatedV14Bootstrapping, false otherwise.
-     */
-    default boolean useV14Bootstrap() {
-        return getBooleanProperty(SERVLET_PARAMETER_USE_V14_BOOTSTRAP, false);
-    }
+public interface DeploymentConfiguration
+        extends AbstractConfiguration, Serializable {
 
     /**
      * Returns whether the server provides timing info to the client.
@@ -195,6 +180,7 @@ <T> T getApplicationOrSystemProperty(String propertyName, T defaultValue,
      * @return the property value, or the passed default value if no property
      *         value is found
      */
+    @Override
     default String getStringProperty(String propertyName, String defaultValue) {
         return getApplicationOrSystemProperty(propertyName, defaultValue,
                 Function.identity());
@@ -224,6 +210,7 @@ default String getStringProperty(String propertyName, String defaultValue) {
      * @throws IllegalArgumentException
      *             if property value string is not a boolean value
      */
+    @Override
     default boolean getBooleanProperty(String propertyName,
             boolean defaultValue) throws IllegalArgumentException {
         String booleanString = getStringProperty(propertyName, null);
@@ -283,7 +270,8 @@ default boolean disableAutomaticServletRegistration() {
      *         <code>false</code> to not serve Brotli files.
      */
     default boolean isBrotli() {
-        return getBooleanProperty(InitParameters.SERVLET_PARAMETER_BROTLI, false);
+        return getBooleanProperty(InitParameters.SERVLET_PARAMETER_BROTLI,
+                false);
     }
 
     default String getCompiledWebComponentsPath() {
@@ -295,8 +283,8 @@ default String getCompiledWebComponentsPath() {
      * Returns an array with polyfills to be loaded when the app is loaded.
      *
      * The default value is empty, but it can be changed by setting the
-     * {@link InitParameters#SERVLET_PARAMETER_POLYFILLS} as a comma separated list
-     * of JS files to load.
+     * {@link InitParameters#SERVLET_PARAMETER_POLYFILLS} as a comma separated
+     * list of JS files to load.
      *
      * @return polyfills to load
      */
@@ -308,16 +296,6 @@ default List<String> getPolyfills() {
                 .collect(Collectors.toList());
     }
 
-    /**
-     * Get if the dev server should be enabled. True by default
-     *
-     * @return true if dev server should be used
-     */
-    default boolean enableDevServer() {
-        return getBooleanProperty(InitParameters.SERVLET_PARAMETER_ENABLE_DEV_SERVER,
-                true);
-    }
-
     /**
      * Get if the dev server should be reused on each reload. True by default,
      * set it to false in tests so as dev server is not kept as a daemon after
@@ -326,8 +304,8 @@ default boolean enableDevServer() {
      * @return true if dev server should be reused
      */
     default boolean reuseDevServer() {
-        return getBooleanProperty(InitParameters.SERVLET_PARAMETER_REUSE_DEV_SERVER,
-                true);
+        return getBooleanProperty(
+                InitParameters.SERVLET_PARAMETER_REUSE_DEV_SERVER, true);
     }
 
     /**
@@ -377,18 +355,9 @@ default boolean isEagerServerLoad() {
     /**
      * Checks if dev mode live reload is enabled or not.
      *
-     * @return {@code true} if dev mode live reload is enabled, {@code false} otherwise
+     * @return {@code true} if dev mode live reload is enabled, {@code false}
+     *         otherwise
      */
     boolean isDevModeLiveReloadEnabled();
 
-    /**
-     * Returns whether pnpm is enabled or not.
-     *
-     * @return {@code true} if enabled, {@code false} if not
-     * @since 2.2
-     */
-    default boolean isPnpmEnabled() {
-        return getBooleanProperty(InitParameters.SERVLET_PARAMETER_ENABLE_PNPM,
-                Boolean.valueOf(Constants.ENABLE_PNPM_DEFAULT_STRING));
-    }
 }

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

@@ -0,0 +1,97 @@
+/*
+ * Copyright 2000-2020 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.server;
+
+import java.io.Serializable;
+
+import static com.vaadin.flow.server.InitParameters.SERVLET_PARAMETER_USE_V14_BOOTSTRAP;
+
+/**
+ * Defines a base contract for configuration (e.g. on an application level,
+ * servlet level,...).
+ * 
+ * @author Vaadin Ltd
+ * @since
+ *
+ */
+public interface AbstractConfiguration extends Serializable {
+    /**
+     * Returns whether Vaadin is in production mode.
+     *
+     * @return true if in production mode, false otherwise.
+     */
+    boolean isProductionMode();
+
+    /**
+     * Get if the dev server should be enabled. True by default
+     *
+     * @return true if dev server should be used
+     */
+    default boolean enableDevServer() {
+        return getBooleanProperty(
+                InitParameters.SERVLET_PARAMETER_ENABLE_DEV_SERVER, true);
+    }
+
+    /**
+     * Returns whether Vaadin is running in useDeprecatedV14Bootstrapping.
+     *
+     * @return true if in useDeprecatedV14Bootstrapping, false otherwise.
+     */
+    default boolean useV14Bootstrap() {
+        return getBooleanProperty(SERVLET_PARAMETER_USE_V14_BOOTSTRAP, false);
+    }
+
+    /**
+     * Gets a configured property as a string.
+     *
+     * @param name
+     *            The simple of the property, in some contexts, lookup might be
+     *            performed using variations of the provided name.
+     * @param defaultValue
+     *            the default value that should be used if no value has been
+     *            defined
+     * @return the property value, or the passed default value if no property
+     *         value is found
+     */
+    String getStringProperty(String name, String defaultValue);
+
+    /**
+     * Gets a configured property as a boolean.
+     *
+     *
+     * @param name
+     *            The simple of the property, in some contexts, lookup might be
+     *            performed using variations of the provided name.
+     * @param defaultValue
+     *            the default value that should be used if no value has been
+     *            defined
+     * @return the property value, or the passed default value if no property
+     *         value is found
+     *
+     */
+    boolean getBooleanProperty(String name, boolean defaultValue);
+
+    /**
+     * Returns whether pnpm is enabled or not.
+     *
+     * @return {@code true} if enabled, {@code false} if not
+     */
+    default boolean isPnpmEnabled() {
+        return getBooleanProperty(InitParameters.SERVLET_PARAMETER_ENABLE_PNPM,
+                Boolean.valueOf(Constants.ENABLE_PNPM_DEFAULT_STRING));
+    }
+
+}

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

@@ -15,6 +15,8 @@
  */
 package com.vaadin.flow.server;
 
+import java.util.Map;
+
 import com.vaadin.flow.component.UI;
 import com.vaadin.flow.function.DeploymentConfiguration;
 
@@ -26,8 +28,18 @@
  * @author Vaadin Ltd
  * @since 1.0
  */
-public abstract class AbstractDeploymentConfiguration
-        implements DeploymentConfiguration {
+public abstract class AbstractDeploymentConfiguration extends
+        AbstractPropertyConfiguration implements DeploymentConfiguration {
+
+    /**
+     * Creates a new configuration based on {@code properties}.
+     * 
+     * @param properties
+     *            configuration properties
+     */
+    protected AbstractDeploymentConfiguration(Map<String, String> properties) {
+        super(properties);
+    }
 
     @Override
     public String getUIClassName() {