SONAR-9478 Deprecate Settings and introduce new Configuration interface

22 files changed, 344 insertions, 97 deletions

diff --git a/sonar-plugin-api/src/main/java/org/sonar/api/Properties.java b/sonar-plugin-api/src/main/java/org/sonar/api/Properties.java
index 9efca22299a..c38f1ecc257 100644
--- a/sonar-plugin-api/src/main/java/org/sonar/api/Properties.java
+++ b/sonar-plugin-api/src/main/java/org/sonar/api/Properties.java
@@ -21,6 +21,7 @@ package org.sonar.api;
 
 import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
+import org.sonar.api.config.Configuration;
 
 /**
  * Plugin properties. This annotation is only used on classes implementing org.sonar.api.Plugin.
@@ -28,7 +29,7 @@ import java.lang.annotation.RetentionPolicy;
  * Note that {@link org.sonar.api.config.PropertyDefinition} is an alternative, programmatic and recommended approach
  * to declare properties.
  * <br>
- * Effective property values are accessible at runtime through the component {@link org.sonar.api.config.Settings}
+ * Effective property values are accessible at runtime through the component {@link Configuration}
  *
  * @since 1.10
  */
diff --git a/sonar-plugin-api/src/main/java/org/sonar/api/batch/bootstrap/ProjectDefinition.java b/sonar-plugin-api/src/main/java/org/sonar/api/batch/bootstrap/ProjectDefinition.java
index 74cad4f2ae6..9bf8eef05b4 100644
--- a/sonar-plugin-api/src/main/java/org/sonar/api/batch/bootstrap/ProjectDefinition.java
+++ b/sonar-plugin-api/src/main/java/org/sonar/api/batch/bootstrap/ProjectDefinition.java
@@ -186,7 +186,7 @@ public class ProjectDefinition {
     }
     return null;
   }
-  
+
   @CheckForNull
   public String getOriginalVersion() {
     return properties.get(CoreProperties.PROJECT_VERSION_PROPERTY);
@@ -199,7 +199,7 @@ public class ProjectDefinition {
     }
     return version;
   }
-  
+
   @CheckForNull
   public String getOriginalName() {
     return properties.get(CoreProperties.PROJECT_NAME_PROPERTY);
@@ -320,6 +320,7 @@ public class ProjectDefinition {
     return this;
   }
 
+  @CheckForNull
   public ProjectDefinition getParent() {
     return parent;
   }
diff --git a/sonar-plugin-api/src/main/java/org/sonar/api/batch/debt/DebtRemediationFunction.java b/sonar-plugin-api/src/main/java/org/sonar/api/batch/debt/DebtRemediationFunction.java
index 44917519e72..96ff255364c 100644
--- a/sonar-plugin-api/src/main/java/org/sonar/api/batch/debt/DebtRemediationFunction.java
+++ b/sonar-plugin-api/src/main/java/org/sonar/api/batch/debt/DebtRemediationFunction.java
@@ -25,6 +25,7 @@ import org.sonar.api.utils.Duration;
 
 /**
  * @since 4.3
+ * @deprecated since 6.5 debt model will soon be unavailable on batch side
  */
 public class DebtRemediationFunction {
 
diff --git a/sonar-plugin-api/src/main/java/org/sonar/api/batch/postjob/PostJobContext.java b/sonar-plugin-api/src/main/java/org/sonar/api/batch/postjob/PostJobContext.java
index 2baa34478d2..cfe881f2866 100644
--- a/sonar-plugin-api/src/main/java/org/sonar/api/batch/postjob/PostJobContext.java
+++ b/sonar-plugin-api/src/main/java/org/sonar/api/batch/postjob/PostJobContext.java
@@ -21,6 +21,7 @@ package org.sonar.api.batch.postjob;
 
 import org.sonar.api.batch.AnalysisMode;
 import org.sonar.api.batch.postjob.issue.PostJobIssue;
+import org.sonar.api.config.Configuration;
 import org.sonar.api.config.Settings;
 
 /**
@@ -30,10 +31,16 @@ import org.sonar.api.config.Settings;
 public interface PostJobContext {
 
   /**
-   * Get settings of the current project.
+   * @deprecated since 6.5 use {@link PostJobContext#config()}
    */
   Settings settings();
 
+  /**
+   * Get configuration of the current project.
+   * @since 6.5
+   */
+  Configuration config();
+
   AnalysisMode analysisMode();
 
   // ----------- Only available in preview mode --------------
diff --git a/sonar-plugin-api/src/main/java/org/sonar/api/batch/sensor/SensorContext.java b/sonar-plugin-api/src/main/java/org/sonar/api/batch/sensor/SensorContext.java
index f47c408ccf0..8da60fb974e 100644
--- a/sonar-plugin-api/src/main/java/org/sonar/api/batch/sensor/SensorContext.java
+++ b/sonar-plugin-api/src/main/java/org/sonar/api/batch/sensor/SensorContext.java
@@ -24,6 +24,7 @@ import org.sonar.api.SonarRuntime;
 import org.sonar.api.batch.fs.FileSystem;
 import org.sonar.api.batch.fs.InputFile;
 import org.sonar.api.batch.fs.InputModule;
+import org.sonar.api.batch.postjob.PostJobContext;
 import org.sonar.api.batch.rule.ActiveRules;
 import org.sonar.api.batch.sensor.coverage.NewCoverage;
 import org.sonar.api.batch.sensor.cpd.NewCpdTokens;
@@ -36,6 +37,7 @@ import org.sonar.api.batch.sensor.measure.Measure;
 import org.sonar.api.batch.sensor.measure.NewMeasure;
 import org.sonar.api.batch.sensor.symbol.NewSymbolTable;
 import org.sonar.api.config.Settings;
+import org.sonar.api.config.Configuration;
 import org.sonar.api.utils.Version;
 
 /**
@@ -46,11 +48,17 @@ import org.sonar.api.utils.Version;
 public interface SensorContext {
 
   /**
-   * Get settings of the current module.
+   * @deprecated since 6.5 use {@link PostJobContext#config()}
    */
   Settings settings();
 
   /**
+   * Get settings of the current module, or of the project for a global Sensor.
+   * @since 6.5
+   */
+  Configuration config();
+
+  /**
    * Get filesystem of the current module.
    */
   FileSystem fileSystem();
diff --git a/sonar-plugin-api/src/main/java/org/sonar/api/batch/sensor/cpd/internal/DefaultCpdTokens.java b/sonar-plugin-api/src/main/java/org/sonar/api/batch/sensor/cpd/internal/DefaultCpdTokens.java
index 3ff672988da..abdb03c9ecc 100644
--- a/sonar-plugin-api/src/main/java/org/sonar/api/batch/sensor/cpd/internal/DefaultCpdTokens.java
+++ b/sonar-plugin-api/src/main/java/org/sonar/api/batch/sensor/cpd/internal/DefaultCpdTokens.java
@@ -28,7 +28,7 @@ import org.sonar.api.batch.fs.internal.PathPattern;
 import org.sonar.api.batch.sensor.cpd.NewCpdTokens;
 import org.sonar.api.batch.sensor.internal.DefaultStorable;
 import org.sonar.api.batch.sensor.internal.SensorStorage;
-import org.sonar.api.config.Settings;
+import org.sonar.api.config.Configuration;
 import org.sonar.duplications.internal.pmd.TokensLine;
 
 import static com.google.common.base.Preconditions.checkState;
@@ -37,7 +37,7 @@ import static java.util.Objects.requireNonNull;
 
 public class DefaultCpdTokens extends DefaultStorable implements NewCpdTokens {
 
-  private final Settings settings;
+  private final Configuration config;
   private final ArrayList<TokensLine> result = new ArrayList<>();
   private InputFile inputFile;
   private int startLine = Integer.MIN_VALUE;
@@ -47,15 +47,15 @@ public class DefaultCpdTokens extends DefaultStorable implements NewCpdTokens {
   private TextRange lastRange;
   private boolean excluded;
 
-  public DefaultCpdTokens(Settings settings, SensorStorage storage) {
+  public DefaultCpdTokens(Configuration config, SensorStorage storage) {
     super(storage);
-    this.settings = settings;
+    this.config = config;
   }
 
   @Override
   public DefaultCpdTokens onFile(InputFile inputFile) {
     this.inputFile = requireNonNull(inputFile, "file can't be null");
-    String[] cpdExclusions = settings.getStringArray(CoreProperties.CPD_EXCLUSIONS);
+    String[] cpdExclusions = config.getStringArray(CoreProperties.CPD_EXCLUSIONS);
     for (PathPattern cpdExclusion : PathPattern.create(cpdExclusions)) {
       if (cpdExclusion.match(inputFile)) {
         this.excluded = true;
diff --git a/sonar-plugin-api/src/main/java/org/sonar/api/batch/sensor/internal/SensorContextTester.java b/sonar-plugin-api/src/main/java/org/sonar/api/batch/sensor/internal/SensorContextTester.java
index 4a3d60763ec..711821e7909 100644
--- a/sonar-plugin-api/src/main/java/org/sonar/api/batch/sensor/internal/SensorContextTester.java
+++ b/sonar-plugin-api/src/main/java/org/sonar/api/batch/sensor/internal/SensorContextTester.java
@@ -64,8 +64,10 @@ import org.sonar.api.batch.sensor.measure.NewMeasure;
 import org.sonar.api.batch.sensor.measure.internal.DefaultMeasure;
 import org.sonar.api.batch.sensor.symbol.NewSymbolTable;
 import org.sonar.api.batch.sensor.symbol.internal.DefaultSymbolTable;
-import org.sonar.api.config.MapSettings;
+import org.sonar.api.config.Configuration;
 import org.sonar.api.config.Settings;
+import org.sonar.api.config.internal.ConfigurationBridge;
+import org.sonar.api.config.internal.MapSettings;
 import org.sonar.api.internal.ApiVersion;
 import org.sonar.api.internal.SonarRuntimeImpl;
 import org.sonar.api.measures.Metric;
@@ -122,6 +124,11 @@ public class SensorContextTester implements SensorContext {
     return settings;
   }
 
+  @Override
+  public Configuration config() {
+    return new ConfigurationBridge(settings);
+  }
+
   public SensorContextTester setSettings(Settings settings) {
     this.settings = settings;
     return this;
@@ -269,7 +276,7 @@ public class SensorContextTester implements SensorContext {
 
   @Override
   public NewCpdTokens newCpdTokens() {
-    return new DefaultCpdTokens(settings, sensorStorage);
+    return new DefaultCpdTokens(config(), sensorStorage);
   }
 
   @Override
diff --git a/sonar-plugin-api/src/main/java/org/sonar/api/config/Configuration.java b/sonar-plugin-api/src/main/java/org/sonar/api/config/Configuration.java
new file mode 100644
index 00000000000..f91996a0734
--- /dev/null
+++ b/sonar-plugin-api/src/main/java/org/sonar/api/config/Configuration.java
@@ -0,0 +1,183 @@
+/*
+ * SonarQube
+ * Copyright (C) 2009-2017 SonarSource SA
+ * mailto:info AT sonarsource DOT com
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 3 of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+package org.sonar.api.config;
+
+import java.util.Optional;
+import org.sonar.api.batch.ScannerSide;
+import org.sonar.api.ce.ComputeEngineSide;
+import org.sonar.api.config.internal.MapSettings;
+import org.sonar.api.server.ServerSide;
+import org.sonarsource.api.sonarlint.SonarLintSide;
+
+/**
+ * Component to get effective configuration. Values of properties depend on the runtime environment:
+ * <ul>
+ *   <li>immutable project or module configuration in scanner.</li>
+ *   <li>global configuration in web server. It does not allow to get the settings overridden on projects.</li>
+ *   <li>project configuration in Compute Engine.</li>
+ * </ul>
+ *
+ * <h3>Usage</h3>
+ * <pre>
+ * public class MyExtension {
+ *
+ *   private final Configuration config;
+ *
+ *   public MyExtension(Configuration config) {
+ *     this.config = config;
+ *   }
+ *   public void doSomething() {
+ *     String fooValue = config.get("sonar.foo").orElse(null);
+ *     // ..
+ *   }
+ * }
+ * </pre>
+ *
+ * <h3>Scanner example</h3>
+ * Scanner sensor can get the reference on Configuration directly through SensorContext,
+ * without injecting the component into constructor.
+ *
+ * <pre>
+ * public class MySensor implements Sensor {
+ *   {@literal @}Override
+ *   public void execute(SensorContext context) {
+ *     String fooValue = context.config().get("sonar.foo").orElse(null);
+ *     // ..
+ *   }
+ * }
+ * </pre>
+ *
+ * <p>
+ * For testing, and only for testing, the in-memory implementation {@link MapSettings} can be used.
+ * <pre>
+ * {@literal @}Test
+ * public void my_test() {
+ *   MapSettings settings = new MapSettings();
+ *   settings.setProperty("foo", "bar");
+ *   MyExtension underTest = new MyExtension(settings.asConfig());
+ *   // ...
+ * }
+ * </pre>
+ *
+ * @see MapSettings
+ * @see PropertyDefinition
+ * @since 6.5
+ */
+@ScannerSide
+@ServerSide
+@ComputeEngineSide
+@SonarLintSide
+public interface Configuration {
+
+  /**
+   * The effective value of the specified property. Can return {@code Optional#empty()} if the property is not set and has no defined default value.
+   * <p>
+   * If the property is encrypted with a secret key, then the returned value is decrypted.
+   * </p>
+   *
+   * @throws IllegalStateException if value is encrypted but fails to be decrypted.
+   */
+  Optional<String> get(String key);
+
+  /**
+   * @return {@code true} if the property has a non-default value, else {@code false}.
+   */
+  boolean hasKey(String key);
+
+  /**
+   * Used to read multi-valued properties. 
+   * <p>
+   * See {@link PropertyDefinition.Builder#multiValues(boolean)}
+   * Multi-valued properties coming from scanner are parsed as CSV lines (ie comma separator and optional double quotes to escape values).
+   * Non quoted values are trimmed.
+   * <br>
+   * Examples :
+   * <ul>
+   * <li>"one,two,three " -&gt; ["one", "two", "three"]</li>
+   * <li>"  one, two, three " -&gt; ["one", "two", "three"]</li>
+   * <li>"one, , three" -&gt; ["one", "", "three"]</li>
+   * <li>"one,\"two,three\",\" four \"" -&gt; ["one", "two,three", " four "]</li>
+   * </ul>
+   */
+  String[] getStringArray(String key);
+
+  /**
+   * Effective value as boolean. It is {@code empty} if {@link #get(String)} is empty or if it
+   * does not return {@code "true"}, even if it's not a boolean representation.
+   * @return {@code true} if the effective value is {@code "true"}, {@code false} for any other non empty value. 
+   * If the property does not have value nor default value, then {@code empty} is returned.
+   */
+  default Optional<Boolean> getBoolean(String key) {
+    return get(key).map(Boolean::parseBoolean);
+  }
+
+  /**
+   * Effective value as {@code int}.
+   * @return the value as {@code int}. If the property does not have value nor default value, then {@code empty} is returned.
+   * @throws NumberFormatException if value is not empty and is not a parsable integer
+   */
+  default Optional<Integer> getInt(String key) {
+    try {
+      return get(key).map(Integer::parseInt);
+    } catch (NumberFormatException e) {
+      throw new IllegalStateException(String.format("The property '%s' is not an int value: %s", key, e.getMessage()));
+    }
+  }
+
+  /**
+   * Effective value as {@code long}.
+   * @return the value as {@code long}. If the property does not have value nor default value, then {@code empty} is returned.
+   * @throws NumberFormatException if value is not empty and is not a parsable {@code long}
+   */
+  default Optional<Long> getLong(String key) {
+    try {
+      return get(key).map(Long::parseLong);
+    } catch (NumberFormatException e) {
+      throw new IllegalStateException(String.format("The property '%s' is not an long value: %s", key, e.getMessage()));
+    }
+  }
+
+  /**
+   * Effective value as {@code Float}.
+   * @return the value as {@code Float}. If the property does not have value nor default value, then {@code empty} is returned.
+   * @throws NumberFormatException if value is not empty and is not a parsable number
+   */
+  default Optional<Float> getFloat(String key) {
+    try {
+      return get(key).map(Float::valueOf);
+    } catch (NumberFormatException e) {
+      throw new IllegalStateException(String.format("The property '%s' is not an float value: %s", key, e.getMessage()));
+    }
+  }
+
+  /**
+   * Effective value as {@code Double}.
+   * @return the value as {@code Double}. If the property does not have value nor default value, then {@code empty} is returned.
+   * @throws NumberFormatException if value is not empty and is not a parsable number
+   */
+  default Optional<Double> getDouble(String key) {
+    try {
+      return get(key).map(Double::valueOf);
+    } catch (NumberFormatException e) {
+      throw new IllegalStateException(String.format("The property '%s' is not an double value: %s", key, e.getMessage()));
+    }
+  }
+
+}
diff --git a/sonar-plugin-api/src/main/java/org/sonar/api/config/EmailSettings.java b/sonar-plugin-api/src/main/java/org/sonar/api/config/EmailSettings.java
index dc449884522..dae2594593a 100644
--- a/sonar-plugin-api/src/main/java/org/sonar/api/config/EmailSettings.java
+++ b/sonar-plugin-api/src/main/java/org/sonar/api/config/EmailSettings.java
@@ -21,7 +21,6 @@ package org.sonar.api.config;
 
 import java.util.List;
 import org.sonar.api.PropertyType;
-import org.sonar.api.batch.ScannerSide;
 import org.sonar.api.ce.ComputeEngineSide;
 import org.sonar.api.server.ServerSide;
 
@@ -34,11 +33,8 @@ import static org.sonar.api.PropertyType.INTEGER;
 import static org.sonar.api.PropertyType.SINGLE_SELECT_LIST;
 
 /**
- * If batch extensions use this component, then batch must be executed with administrator rights (see properties sonar.login and sonar.password)
- *
  * @since 3.2
  */
-@ScannerSide
 @ServerSide
 @ComputeEngineSide
 public class EmailSettings {
diff --git a/sonar-plugin-api/src/main/java/org/sonar/api/config/PropertyDefinition.java b/sonar-plugin-api/src/main/java/org/sonar/api/config/PropertyDefinition.java
index 02d64853e8e..13c407d000b 100644
--- a/sonar-plugin-api/src/main/java/org/sonar/api/config/PropertyDefinition.java
+++ b/sonar-plugin-api/src/main/java/org/sonar/api/config/PropertyDefinition.java
@@ -57,7 +57,7 @@ import static org.sonar.api.PropertyType.REGULAR_EXPRESSION;
 import static org.sonar.api.PropertyType.SINGLE_SELECT_LIST;
 
 /**
- * Declare a plugin property. Values are available at runtime through the component {@link Settings}.
+ * Declare a plugin property. Values are available at runtime through the components {@link Settings} or {@link org.sonar.api.Configuration.SettingsReader}.
  * <br>
  * It's the programmatic alternative to the annotation {@link org.sonar.api.Property}. It is more
  * testable and adds new features like sub-categories and ordering.
diff --git a/sonar-plugin-api/src/main/java/org/sonar/api/config/PropertyDefinitions.java b/sonar-plugin-api/src/main/java/org/sonar/api/config/PropertyDefinitions.java
index 9a0834b62be..b0e5275674f 100644
--- a/sonar-plugin-api/src/main/java/org/sonar/api/config/PropertyDefinitions.java
+++ b/sonar-plugin-api/src/main/java/org/sonar/api/config/PropertyDefinitions.java
@@ -165,6 +165,7 @@ public final class PropertyDefinitions {
     return byCategory;
   }
 
+  @CheckForNull
   public String getDefaultValue(String key) {
     PropertyDefinition def = get(key);
     if (def == null) {
diff --git a/sonar-plugin-api/src/main/java/org/sonar/api/config/Settings.java b/sonar-plugin-api/src/main/java/org/sonar/api/config/Settings.java
index 7e182dcd555..20fb15bff45 100644
--- a/sonar-plugin-api/src/main/java/org/sonar/api/config/Settings.java
+++ b/sonar-plugin-api/src/main/java/org/sonar/api/config/Settings.java
@@ -35,69 +35,19 @@ import org.sonar.api.batch.ScannerSide;
 import org.sonar.api.ce.ComputeEngineSide;
 import org.sonar.api.server.ServerSide;
 import org.sonar.api.utils.DateUtils;
+import org.sonarsource.api.sonarlint.SonarLintSide;
 
 import static java.util.Objects.requireNonNull;
 import static org.apache.commons.lang.StringUtils.trim;
 
 /**
- * Component to get effective settings. Values of properties depend on the runtime environment:
- * <ul>
- *   <li>project settings in scanner.</li>
- *   <li>global settings in web server. It does not allow to get the settings overridden on projects.</li>
- *   <li>project settings in Compute Engine.</li>
- * </ul>
- *
- * <h3>Usage</h3>
- * <pre>
- * public class MyExtension {
- *
- *   private final Settings settings;
- *
- *   public MyExtension(Settings settings) {
- *     this.settings = settings;
- *   }
- *   public void doSomething() {
- *     String fooValue = settings.getString("sonar.foo");
- *     // ..
- *   }
- * }
- * </pre>
- *
- * <h3>Scanner example</h3>
- * Scanner sensor can get the reference on Settings directly through SensorContext,
- * without injecting the component into constructor.
- *
- * <pre>
- * public class MySensor implements Sensor {
- *   {@literal @}Override
- *   public void execute(SensorContext context) {
- *     String fooValue = context.settings().getString("sonar.foo");
- *     // ..
- *   }
- * }
- * </pre>
- *
- * <p>
- * For testing, and only for testing, the in-memory implementation {@link MapSettings} can be used.
- * <pre>
- * {@literal @}Test
- * public void my_test() {
- *   Settings settings = new MapSettings();
- *   settings.setProperty("foo", "bar");
- *   MyExtension underTest = new MyExtension(settings);
- *   // ...
- * }
- * </pre>
- *
- * History - this class is abstract since 6.1.
- *
- * @see MapSettings
- * @see PropertyDefinition
- * @since 2.12
+ * @deprecated since 6.5 use {@link Configuration}
  */
-@ScannerSide
 @ServerSide
 @ComputeEngineSide
+@ScannerSide
+@SonarLintSide
+@Deprecated
 public abstract class Settings {
 
   private final PropertyDefinitions definitions;
diff --git a/sonar-plugin-api/src/main/java/org/sonar/api/config/internal/ConfigurationBridge.java b/sonar-plugin-api/src/main/java/org/sonar/api/config/internal/ConfigurationBridge.java
new file mode 100644
index 00000000000..4e8ef584fd3
--- /dev/null
+++ b/sonar-plugin-api/src/main/java/org/sonar/api/config/internal/ConfigurationBridge.java
@@ -0,0 +1,52 @@
+/*
+ * SonarQube
+ * Copyright (C) 2009-2017 SonarSource SA
+ * mailto:info AT sonarsource DOT com
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 3 of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+package org.sonar.api.config.internal;
+
+import java.util.Optional;
+import org.sonar.api.config.Settings;
+import org.sonar.api.config.Configuration;
+
+/**
+ * Used to help migration from {@link Settings} to {@link Configuration}
+ */
+public class ConfigurationBridge implements Configuration {
+
+  private final Settings settings;
+
+  public ConfigurationBridge(Settings settings) {
+    this.settings = settings;
+  }
+
+  @Override
+  public Optional<String> get(String key) {
+    return Optional.ofNullable(settings.getString(key));
+  }
+
+  @Override
+  public boolean hasKey(String key) {
+    return settings.hasKey(key);
+  }
+
+  @Override
+  public String[] getStringArray(String key) {
+    return settings.getStringArray(key);
+  }
+
+}
diff --git a/sonar-plugin-api/src/main/java/org/sonar/api/config/MapSettings.java b/sonar-plugin-api/src/main/java/org/sonar/api/config/internal/MapSettings.java
index 5a73567a808..6d45e12ddb6 100644
--- a/sonar-plugin-api/src/main/java/org/sonar/api/config/MapSettings.java
+++ b/sonar-plugin-api/src/main/java/org/sonar/api/config/internal/MapSettings.java
@@ -17,11 +17,15 @@
  * along with this program; if not, write to the Free Software Foundation,
  * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  */
-package org.sonar.api.config;
+package org.sonar.api.config.internal;
 
 import java.util.HashMap;
 import java.util.Map;
 import java.util.Optional;
+import org.sonar.api.config.Configuration;
+import org.sonar.api.config.Encryption;
+import org.sonar.api.config.PropertyDefinitions;
+import org.sonar.api.config.Settings;
 
 import static java.util.Collections.unmodifiableMap;
 
@@ -36,13 +40,15 @@ import static java.util.Collections.unmodifiableMap;
 public class MapSettings extends Settings {
 
   private final Map<String, String> props = new HashMap<>();
+  private final ConfigurationBridge configurationBridge;
 
   public MapSettings() {
-    super(new PropertyDefinitions(), new Encryption(null));
+    this(new PropertyDefinitions());
   }
 
   public MapSettings(PropertyDefinitions definitions) {
     super(definitions, new Encryption(null));
+    configurationBridge = new ConfigurationBridge(this);
   }
 
   @Override
@@ -72,4 +78,12 @@ public class MapSettings extends Settings {
     props.clear();
     return this;
   }
+
+  /**
+   * @return a {@link Configuration} proxy on top of this existing {@link Settings} implementation. Changes are reflected in the {@link Configuration} object.
+   * @since 6.5
+   */
+  public Configuration asConfig() {
+    return configurationBridge;
+  }
 }
diff --git a/sonar-plugin-api/src/main/java/org/sonar/api/config/internal/package-info.java b/sonar-plugin-api/src/main/java/org/sonar/api/config/internal/package-info.java
new file mode 100644
index 00000000000..4fb297e0a30
--- /dev/null
+++ b/sonar-plugin-api/src/main/java/org/sonar/api/config/internal/package-info.java
@@ -0,0 +1,23 @@
+/*
+ * SonarQube
+ * Copyright (C) 2009-2017 SonarSource SA
+ * mailto:info AT sonarsource DOT com
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 3 of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+@ParametersAreNonnullByDefault
+package org.sonar.api.config.internal;
+
+import javax.annotation.ParametersAreNonnullByDefault;
diff --git a/sonar-plugin-api/src/main/java/org/sonar/api/scan/filesystem/FileExclusions.java b/sonar-plugin-api/src/main/java/org/sonar/api/scan/filesystem/FileExclusions.java
index 1a071e62758..af7e9550b96 100644
--- a/sonar-plugin-api/src/main/java/org/sonar/api/scan/filesystem/FileExclusions.java
+++ b/sonar-plugin-api/src/main/java/org/sonar/api/scan/filesystem/FileExclusions.java
@@ -24,7 +24,7 @@ import java.util.stream.Stream;
 import org.apache.commons.lang.StringUtils;
 import org.sonar.api.CoreProperties;
 import org.sonar.api.batch.ScannerSide;
-import org.sonar.api.config.Settings;
+import org.sonar.api.config.Configuration;
 
 /**
  * Configuration of file inclusions and exclusions.
@@ -35,9 +35,9 @@ import org.sonar.api.config.Settings;
  */
 @ScannerSide
 public class FileExclusions {
-  private final Settings settings;
+  private final Configuration settings;
 
-  public FileExclusions(Settings settings) {
+  public FileExclusions(Configuration settings) {
     this.settings = settings;
   }
 
diff --git a/sonar-plugin-api/src/test/java/org/sonar/api/batch/bootstrap/ProjectBuilderTest.java b/sonar-plugin-api/src/test/java/org/sonar/api/batch/bootstrap/ProjectBuilderTest.java
index b8b08a4e4dc..72fd4a8539c 100644
--- a/sonar-plugin-api/src/test/java/org/sonar/api/batch/bootstrap/ProjectBuilderTest.java
+++ b/sonar-plugin-api/src/test/java/org/sonar/api/batch/bootstrap/ProjectBuilderTest.java
@@ -23,7 +23,7 @@ import java.io.File;
 import org.junit.Test;
 import org.sonar.api.batch.bootstrap.internal.ProjectBuilderContext;
 import org.sonar.api.config.Settings;
-import org.sonar.api.config.MapSettings;
+import org.sonar.api.config.internal.MapSettings;
 
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.hamcrest.core.Is.is;
diff --git a/sonar-plugin-api/src/test/java/org/sonar/api/batch/sensor/cpd/internal/DefaultCpdTokensTest.java b/sonar-plugin-api/src/test/java/org/sonar/api/batch/sensor/cpd/internal/DefaultCpdTokensTest.java
index 9b20b94d700..62a268f00f7 100644
--- a/sonar-plugin-api/src/test/java/org/sonar/api/batch/sensor/cpd/internal/DefaultCpdTokensTest.java
+++ b/sonar-plugin-api/src/test/java/org/sonar/api/batch/sensor/cpd/internal/DefaultCpdTokensTest.java
@@ -24,7 +24,7 @@ import org.sonar.api.batch.fs.InputFile;
 import org.sonar.api.batch.fs.internal.TestInputFileBuilder;
 import org.sonar.api.batch.sensor.internal.SensorStorage;
 import org.sonar.api.config.Settings;
-import org.sonar.api.config.MapSettings;
+import org.sonar.api.config.internal.MapSettings;
 
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.fail;
@@ -44,7 +44,7 @@ public class DefaultCpdTokensTest {
   @Test
   public void save_no_tokens() {
     SensorStorage sensorStorage = mock(SensorStorage.class);
-    DefaultCpdTokens tokens = new DefaultCpdTokens(new MapSettings(), sensorStorage)
+    DefaultCpdTokens tokens = new DefaultCpdTokens(new MapSettings().asConfig(), sensorStorage)
       .onFile(INPUT_FILE);
 
     tokens.save();
@@ -57,7 +57,7 @@ public class DefaultCpdTokensTest {
   @Test
   public void save_one_token() {
     SensorStorage sensorStorage = mock(SensorStorage.class);
-    DefaultCpdTokens tokens = new DefaultCpdTokens(new MapSettings(), sensorStorage)
+    DefaultCpdTokens tokens = new DefaultCpdTokens(new MapSettings().asConfig(), sensorStorage)
       .onFile(INPUT_FILE)
       .addToken(INPUT_FILE.newRange(1, 2, 1, 5), "foo");
 
@@ -71,9 +71,9 @@ public class DefaultCpdTokensTest {
   @Test
   public void handle_exclusions_by_pattern() {
     SensorStorage sensorStorage = mock(SensorStorage.class);
-    Settings settings = new MapSettings();
+    MapSettings settings = new MapSettings();
     settings.setProperty("sonar.cpd.exclusions", "src/Foo.java,another");
-    DefaultCpdTokens tokens = new DefaultCpdTokens(settings, sensorStorage)
+    DefaultCpdTokens tokens = new DefaultCpdTokens(settings.asConfig(), sensorStorage)
       .onFile(INPUT_FILE)
       .addToken(INPUT_FILE.newRange(1, 2, 1, 5), "foo");
 
@@ -87,7 +87,7 @@ public class DefaultCpdTokensTest {
   @Test
   public void save_many_tokens() {
     SensorStorage sensorStorage = mock(SensorStorage.class);
-    DefaultCpdTokens tokens = new DefaultCpdTokens(new MapSettings(), sensorStorage)
+    DefaultCpdTokens tokens = new DefaultCpdTokens(new MapSettings().asConfig(), sensorStorage)
       .onFile(INPUT_FILE)
       .addToken(INPUT_FILE.newRange(1, 2, 1, 5), "foo")
       .addToken(INPUT_FILE.newRange(1, 6, 1, 10), "bar")
@@ -108,7 +108,7 @@ public class DefaultCpdTokensTest {
   @Test
   public void basic_validation() {
     SensorStorage sensorStorage = mock(SensorStorage.class);
-    DefaultCpdTokens tokens = new DefaultCpdTokens(new MapSettings(), sensorStorage);
+    DefaultCpdTokens tokens = new DefaultCpdTokens(new MapSettings().asConfig(), sensorStorage);
     try {
       tokens.save();
       fail("Expected exception");
@@ -138,7 +138,7 @@ public class DefaultCpdTokensTest {
   @Test
   public void validate_tokens_order() {
     SensorStorage sensorStorage = mock(SensorStorage.class);
-    DefaultCpdTokens tokens = new DefaultCpdTokens(new MapSettings(), sensorStorage)
+    DefaultCpdTokens tokens = new DefaultCpdTokens(new MapSettings().asConfig(), sensorStorage)
       .onFile(INPUT_FILE)
       .addToken(INPUT_FILE.newRange(1, 6, 1, 10), "bar");
 
diff --git a/sonar-plugin-api/src/test/java/org/sonar/api/batch/sensor/internal/SensorContextTesterTest.java b/sonar-plugin-api/src/test/java/org/sonar/api/batch/sensor/internal/SensorContextTesterTest.java
index 4893f6fdd63..566facb4a1a 100644
--- a/sonar-plugin-api/src/test/java/org/sonar/api/batch/sensor/internal/SensorContextTesterTest.java
+++ b/sonar-plugin-api/src/test/java/org/sonar/api/batch/sensor/internal/SensorContextTesterTest.java
@@ -38,8 +38,8 @@ import org.sonar.api.batch.sensor.error.NewAnalysisError;
 import org.sonar.api.batch.sensor.highlighting.TypeOfText;
 import org.sonar.api.batch.sensor.issue.NewIssue;
 import org.sonar.api.batch.sensor.symbol.NewSymbolTable;
-import org.sonar.api.config.MapSettings;
 import org.sonar.api.config.Settings;
+import org.sonar.api.config.internal.MapSettings;
 import org.sonar.api.measures.CoreMetrics;
 import org.sonar.api.rule.RuleKey;
 import org.sonar.api.utils.SonarException;
diff --git a/sonar-plugin-api/src/test/java/org/sonar/api/config/EmailSettingsTest.java b/sonar-plugin-api/src/test/java/org/sonar/api/config/EmailSettingsTest.java
index b5504b5d2b3..507ab123b08 100644
--- a/sonar-plugin-api/src/test/java/org/sonar/api/config/EmailSettingsTest.java
+++ b/sonar-plugin-api/src/test/java/org/sonar/api/config/EmailSettingsTest.java
@@ -21,6 +21,7 @@ package org.sonar.api.config;
 
 import org.junit.Test;
 import org.sonar.api.CoreProperties;
+import org.sonar.api.config.internal.MapSettings;
 
 import static org.assertj.core.api.Assertions.assertThat;
 
diff --git a/sonar-plugin-api/src/test/java/org/sonar/api/config/MapSettingsTest.java b/sonar-plugin-api/src/test/java/org/sonar/api/config/internal/MapSettingsTest.java
index 284d35ea507..e28a73cdb9c 100644
--- a/sonar-plugin-api/src/test/java/org/sonar/api/config/MapSettingsTest.java
+++ b/sonar-plugin-api/src/test/java/org/sonar/api/config/internal/MapSettingsTest.java
@@ -17,7 +17,7 @@
  * along with this program; if not, write to the Free Software Foundation,
  * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  */
-package org.sonar.api.config;
+package org.sonar.api.config.internal;
 
 import java.util.Date;
 import org.assertj.core.data.Offset;
@@ -28,6 +28,9 @@ import org.junit.rules.ExpectedException;
 import org.sonar.api.Properties;
 import org.sonar.api.Property;
 import org.sonar.api.PropertyType;
+import org.sonar.api.config.PropertyDefinitions;
+import org.sonar.api.config.Settings;
+import org.sonar.api.config.internal.MapSettings;
 import org.sonar.api.utils.DateUtils;
 
 import static org.assertj.core.api.Assertions.assertThat;
diff --git a/sonar-plugin-api/src/test/java/org/sonar/api/scan/filesystem/FileExclusionsTest.java b/sonar-plugin-api/src/test/java/org/sonar/api/scan/filesystem/FileExclusionsTest.java
index bd98496fdf9..bd03eec7fed 100644
--- a/sonar-plugin-api/src/test/java/org/sonar/api/scan/filesystem/FileExclusionsTest.java
+++ b/sonar-plugin-api/src/test/java/org/sonar/api/scan/filesystem/FileExclusionsTest.java
@@ -21,27 +21,26 @@ package org.sonar.api.scan.filesystem;
 
 import org.junit.Test;
 import org.sonar.api.CoreProperties;
-import org.sonar.api.config.Settings;
-import org.sonar.api.config.MapSettings;
+import org.sonar.api.config.internal.MapSettings;
 
 import static org.assertj.core.api.Assertions.assertThat;
 
 public class FileExclusionsTest {
   @Test
   public void ignore_inclusion_of_world() {
-    Settings settings = new MapSettings();
+    MapSettings settings = new MapSettings();
     settings.setProperty(CoreProperties.PROJECT_INCLUSIONS_PROPERTY, "**/*");
     settings.setProperty(CoreProperties.PROJECT_TEST_INCLUSIONS_PROPERTY, "**/*");
-    assertThat(new FileExclusions(settings).sourceInclusions()).isEmpty();
-    assertThat(new FileExclusions(settings).testInclusions()).isEmpty();
+    assertThat(new FileExclusions(settings.asConfig()).sourceInclusions()).isEmpty();
+    assertThat(new FileExclusions(settings.asConfig()).testInclusions()).isEmpty();
   }
 
   @Test
   public void load_inclusions() {
-    Settings settings = new MapSettings();
+    MapSettings settings = new MapSettings();
     settings.setProperty(CoreProperties.PROJECT_INCLUSIONS_PROPERTY, "**/*Foo.java");
     settings.setProperty(CoreProperties.PROJECT_TEST_INCLUSIONS_PROPERTY, "**/*FooTest.java");
-    FileExclusions moduleExclusions = new FileExclusions(settings);
+    FileExclusions moduleExclusions = new FileExclusions(settings.asConfig());
 
     assertThat(moduleExclusions.sourceInclusions()).containsOnly("**/*Foo.java");
     assertThat(moduleExclusions.testInclusions()).containsOnly("**/*FooTest.java");
@@ -49,10 +48,10 @@ public class FileExclusionsTest {
 
   @Test
   public void load_exclusions() {
-    Settings settings = new MapSettings();
+    MapSettings settings = new MapSettings();
     settings.setProperty(CoreProperties.PROJECT_EXCLUSIONS_PROPERTY, "**/*Foo.java");
     settings.setProperty(CoreProperties.PROJECT_TEST_EXCLUSIONS_PROPERTY, "**/*FooTest.java");
-    FileExclusions moduleExclusions = new FileExclusions(settings);
+    FileExclusions moduleExclusions = new FileExclusions(settings.asConfig());
 
     assertThat(moduleExclusions.sourceInclusions()).isEmpty();
     assertThat(moduleExclusions.sourceExclusions()).containsOnly("**/*Foo.java");