XCOMMONS-2921: Add support for overwritting the configuration from the execution context

xwiki-commons-core/xwiki-commons-configuration/xwiki-commons-configuration-api/pom.xml

@@ -32,7 +32,7 @@
   <packaging>jar</packaging>
   <description>Provides the infrastructure for components needing configuration data</description>
   <properties>
-    <xwiki.jacoco.instructionRatio>0.00</xwiki.jacoco.instructionRatio>
+    <xwiki.jacoco.instructionRatio>0.54</xwiki.jacoco.instructionRatio>
     <!-- Name to display by the Extension Manager -->
     <xwiki.extension.name>Configuration API</xwiki.extension.name>
     <!-- Category to display in the Extension Manager -->
@@ -44,10 +44,21 @@
       <artifactId>xwiki-commons-component-api</artifactId>
       <version>${project.version}</version>
     </dependency>
+    <dependency>
+      <groupId>org.xwiki.commons</groupId>
+      <artifactId>xwiki-commons-context</artifactId>
+      <version>${project.version}</version>
+    </dependency>
     <dependency>
       <groupId>commons-beanutils</groupId>
       <artifactId>commons-beanutils</artifactId>
     </dependency>
+    <!-- Test dependencies -->
+    <dependency>
+      <groupId>org.xwiki.commons</groupId>
+      <artifactId>xwiki-commons-tool-test-component</artifactId>
+      <version>${project.version}</version>
+      <scope>test</scope>
+    </dependency>
   </dependencies>
-</project>
-
+</project>

xwiki-commons-core/xwiki-commons-configuration/xwiki-commons-configuration-api/src/main/java/org/xwiki/configuration/ConfigurationSource.java

@@ -23,6 +23,7 @@
 import java.util.Map;
 
 import org.xwiki.component.annotation.Role;
+import org.xwiki.stability.Unstable;
 
 /**
  * @version $Id$
@@ -96,10 +97,12 @@ default <T> T getProperty(String key, Class<T> valueClass, T defaultValue)
     boolean isEmpty();
 
     /**
-     * Set a property, this will replace any previously set values.
+     * Sets the value of a property, replacing any previously set values. Note that setting a property to {@code null}
+     * doesn't necessarily remove it from the configuration source. If you want to remove a property, use
+     * {@link #removeProperty(String)} instead.
      *
-     * @param key The key of the property to change
-     * @param value The new value
+     * @param key the key of the property to change
+     * @param value the new value
      * @throws ConfigurationSaveException when an error occurs during persistence
      * @since 15.9
      * @since 15.5.4
@@ -119,4 +122,21 @@ default void setProperties(Map<String, Object> properties) throws ConfigurationS
     {
         throw new UnsupportedOperationException("Modifying properties of this configuration source is not allowed");
     }
+
+    /**
+     * Removes a property from the configuration source. Calling {@link #containsKey()} on the same key after this
+     * method is executed successfully should return {@code false}.
+     * 
+     * @param key the key of the property to remove
+     * @param <T> the property value type
+     * @return the value of the removed property or {@code null} if the property wasn't set
+     * @throws ConfigurationSaveException when an error occurs during persistence
+     * @since 16.1.0RC1
+     * @since 15.10.6
+     */
+    @Unstable
+    default <T> T removeProperty(String key) throws ConfigurationSaveException
+    {
+        throw new UnsupportedOperationException("Removing a property of this configuration source is not allowed");
+    }
 }

xwiki-commons-core/xwiki-commons-configuration/xwiki-commons-configuration-api/src/main/java/org/xwiki/configuration/TemporaryConfigurationExecutor.java

@@ -0,0 +1,50 @@
+/*
+ * See the NOTICE file distributed with this work for additional
+ * information regarding copyright ownership.
+ *
+ * This 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 2.1 of
+ * the License, or (at your option) any later version.
+ *
+ * This software 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 software; if not, write to the Free
+ * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
+ * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
+ */
+package org.xwiki.configuration;
+
+import java.util.Map;
+import java.util.concurrent.Callable;
+
+import org.xwiki.component.annotation.Role;
+import org.xwiki.stability.Unstable;
+
+/**
+ * Executes a {@link Callable} using a temporary configuration.
+ * 
+ * @version $Id$
+ * @since 16.1.0RC1
+ * @since 15.10.6
+ */
+@Role
+@Unstable
+public interface TemporaryConfigurationExecutor
+{
+    /**
+     * Executes the passed {@link Callable} using the given temporary configuration.
+     *
+     * @param sourceHint indicates the configuration source that should receive the temporary configuration
+     * @param temporaryConfiguration the temporary configuration to use while executing the passed {@link Callable}
+     * @param callable the code to execute
+     * @param <V> the type of value returned by the passed {@link Callable}
+     * @return the value returned by the passed {@link Callable}
+     * @throws Exception if the passed {@link Callable} throws an exception
+     */
+    <V> V call(String sourceHint, Map<String, Object> temporaryConfiguration, Callable<V> callable) throws Exception;
+}

xwiki-commons-core/xwiki-commons-configuration/xwiki-commons-configuration-api/src/main/java/org/xwiki/configuration/internal/AbstractMemoryConfigurationSource.java

@@ -0,0 +1,122 @@
+/*
+ * See the NOTICE file distributed with this work for additional
+ * information regarding copyright ownership.
+ *
+ * This 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 2.1 of
+ * the License, or (at your option) any later version.
+ *
+ * This software 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 software; if not, write to the Free
+ * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
+ * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
+ */
+package org.xwiki.configuration.internal;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Map;
+
+import org.apache.commons.beanutils.ConvertUtils;
+
+/**
+ * Base class for configuration sources that store the configuration in memory.
+ * 
+ * @version $Id$
+ * @since 16.1.0RC1
+ * @since 15.10.6
+ */
+public abstract class AbstractMemoryConfigurationSource extends AbstractConfigurationSource
+{
+    protected abstract Map<String, Object> getProperties();
+
+    @Override
+    public void setProperties(Map<String, Object> newProperties)
+    {
+        Map<String, Object> currentProperties = getProperties();
+        currentProperties.clear();
+        currentProperties.putAll(newProperties);
+    }
+
+    @Override
+    public void setProperty(String key, Object value)
+    {
+        getProperties().put(key, value);
+    }
+
+    @SuppressWarnings("unchecked")
+    @Override
+    public <T> T removeProperty(String key)
+    {
+        return (T) getProperties().remove(key);
+    }
+
+    @SuppressWarnings("unchecked")
+    @Override
+    public <T> T getProperty(String key, T defaultValue)
+    {
+        T result;
+
+        if (getProperties().containsKey(key)) {
+            Object value = getProperties().get(key);
+            if (value != null && defaultValue != null && !defaultValue.getClass().isInstance(value)) {
+                value = ConvertUtils.convert(value, defaultValue.getClass());
+            }
+            result = (T) value;
+        } else {
+            result = defaultValue;
+        }
+
+        return result;
+    }
+
+    @SuppressWarnings("unchecked")
+    @Override
+    public <T> T getProperty(String key, Class<T> valueClass)
+    {
+        T result;
+
+        if (getProperties().containsKey(key)) {
+            Object value = getProperties().get(key);
+            if (value != null && valueClass != null && !valueClass.isInstance(value)) {
+                value = ConvertUtils.convert(value, valueClass);
+            }
+            result = (T) value;
+        } else {
+            result = getDefault(valueClass);
+        }
+
+        return result;
+    }
+
+    @SuppressWarnings("unchecked")
+    @Override
+    public <T> T getProperty(String key)
+    {
+        return (T) getProperties().get(key);
+    }
+
+    @Override
+    public List<String> getKeys()
+    {
+        return new ArrayList<>(getProperties().keySet());
+    }
+
+    @Override
+    public boolean containsKey(String key)
+    {
+        return getProperties().containsKey(key);
+    }
+
+    @Override
+    public boolean isEmpty()
+    {
+        return getProperties().isEmpty();
+    }
+}

xwiki-commons-core/xwiki-commons-configuration/xwiki-commons-configuration-api/src/main/java/org/xwiki/configuration/internal/DefaultTemporaryConfigurationExecutor.java

@@ -0,0 +1,99 @@
+/*
+ * See the NOTICE file distributed with this work for additional
+ * information regarding copyright ownership.
+ *
+ * This 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 2.1 of
+ * the License, or (at your option) any later version.
+ *
+ * This software 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 software; if not, write to the Free
+ * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
+ * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
+ */
+package org.xwiki.configuration.internal;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.concurrent.Callable;
+
+import javax.inject.Inject;
+import javax.inject.Named;
+import javax.inject.Provider;
+import javax.inject.Singleton;
+
+import org.apache.commons.lang3.tuple.ImmutablePair;
+import org.apache.commons.lang3.tuple.Pair;
+import org.xwiki.component.annotation.Component;
+import org.xwiki.component.manager.ComponentLookupException;
+import org.xwiki.component.manager.ComponentManager;
+import org.xwiki.configuration.ConfigurationSaveException;
+import org.xwiki.configuration.ConfigurationSource;
+import org.xwiki.configuration.TemporaryConfigurationExecutor;
+
+/**
+ * Default implementation of {@link TemporaryConfigurationExecutor}.
+ * 
+ * @version $Id$
+ * @since 16.1.0RC1
+ * @since 15.10.6
+ */
+@Component
+@Singleton
+public class DefaultTemporaryConfigurationExecutor implements TemporaryConfigurationExecutor
+{
+    @Inject
+    @Named("context")
+    private Provider<ComponentManager> componentManagerProvider;
+
+    @Override
+    public <V> V call(String sourceHint, Map<String, Object> temporaryConfiguration, Callable<V> callable)
+        throws Exception
+    {
+        ConfigurationSource configurationSource = getConfigurationSource(sourceHint);
+        Map<String, Pair<Boolean, Object>> backup = setConfiguration(configurationSource, temporaryConfiguration);
+        try {
+            return callable.call();
+        } finally {
+            restoreConfiguration(configurationSource, backup);
+        }
+    }
+
+    private ConfigurationSource getConfigurationSource(String sourceHint) throws ComponentLookupException
+    {
+        ComponentManager componentManager = this.componentManagerProvider.get();
+        return componentManager.getInstance(ConfigurationSource.class, sourceHint);
+    }
+
+    private Map<String, Pair<Boolean, Object>> setConfiguration(ConfigurationSource configurationSource,
+        Map<String, Object> temporaryConfiguration) throws ConfigurationSaveException
+    {
+        Map<String, Pair<Boolean, Object>> backup = new HashMap<>();
+        for (Map.Entry<String, Object> entry : temporaryConfiguration.entrySet()) {
+            backup.put(entry.getKey(), new ImmutablePair<>(configurationSource.containsKey(entry.getKey()),
+                configurationSource.getProperty(entry.getKey())));
+            configurationSource.setProperty(entry.getKey(), entry.getValue());
+        }
+        return backup;
+    }
+
+    private void restoreConfiguration(ConfigurationSource configurationSource,
+        Map<String, Pair<Boolean, Object>> backup) throws ConfigurationSaveException
+    {
+        for (Map.Entry<String, Pair<Boolean, Object>> entry : backup.entrySet()) {
+            if (Boolean.TRUE.equals(entry.getValue().getLeft())) {
+                // The property existed before, restore its previous value.
+                configurationSource.setProperty(entry.getKey(), entry.getValue().getRight());
+            } else {
+                // The property didn't exist before, remove it.
+                configurationSource.removeProperty(entry.getKey());
+            }
+        }
+    }
+}