Strict read only mode

persistence/persistence/src/main/java/one/microstream/persistence/exceptions/PersistenceExceptionStoringDisabled.java

@@ -0,0 +1,32 @@
+package one.microstream.persistence.exceptions;
+
+/*-
+ * #%L
+ * MicroStream Persistence
+ * %%
+ * Copyright (C) 2019 - 2022 MicroStream Software
+ * %%
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License 2.0 which is available at
+ * http://www.eclipse.org/legal/epl-2.0.
+ * 
+ * This Source Code may also be made available under the following Secondary
+ * Licenses when the conditions for such availability set forth in the Eclipse
+ * Public License, v. 2.0 are satisfied: GNU General Public License, version 2
+ * with the GNU Classpath Exception which is
+ * available at https://www.gnu.org/software/classpath/license.html.
+ * 
+ * SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
+ * #L%
+ */
+
+public class PersistenceExceptionStoringDisabled extends PersistenceException
+{
+	@Override
+	public String getMessage()
+	{
+		return "Storing is not enabled! " +
+			(super.getMessage() != null ? " Details: " + super.getMessage() : "");
+	}
+
+}

persistence/persistence/src/main/java/one/microstream/persistence/types/PersistenceWriteController.java

@@ -23,7 +23,7 @@
 import static one.microstream.X.notNull;
 
 import one.microstream.afs.types.WriteController;
-import one.microstream.persistence.exceptions.PersistenceException;
+import one.microstream.persistence.exceptions.PersistenceExceptionStoringDisabled;
 
 
 @FunctionalInterface
@@ -36,7 +36,7 @@ public default void validateIsStoringEnabled()
 			return;
 		}
 
-		throw new PersistenceException("Storing is not enabled.");
+		throw new PersistenceExceptionStoringDisabled();
 	}
 
 	public default boolean isStoringEnabled()

storage/storage/src/main/java/one/microstream/storage/types/StorageWriteControllerReadOnlyMode.java

@@ -0,0 +1,149 @@
+package one.microstream.storage.types;
+
+/*-
+ * #%L
+ * MicroStream Storage
+ * %%
+ * Copyright (C) 2019 - 2022 MicroStream Software
+ * %%
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License 2.0 which is available at
+ * http://www.eclipse.org/legal/epl-2.0.
+ * 
+ * This Source Code may also be made available under the following Secondary
+ * Licenses when the conditions for such availability set forth in the Eclipse
+ * Public License, v. 2.0 are satisfied: GNU General Public License, version 2
+ * with the GNU Classpath Exception which is
+ * available at https://www.gnu.org/software/classpath/license.html.
+ * 
+ * SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
+ * #L%
+ */
+
+import org.slf4j.Logger;
+
+import one.microstream.afs.types.WriteController;
+import one.microstream.util.logging.Logging;
+
+/**
+ * {@link StorageWriteController} implementation that
+ * allows to switch between the supplied and a read only
+ * StorageWriteController. If the read only mode is disabled
+ * the supplied StorageWriteController will be used.
+ * 
+ * <br><br>
+ * Setup:
+ * 
+ * <pre> {@code
+ *
+ * final EmbeddedStorageFoundation<?> foundation = EmbeddedStorage.Foundation();
+ *
+ * final StorageWriteControllerReadOnlyMode storageWriteController =
+ *	new StorageWriteControllerReadOnlyMode(foundation.getWriteController());
+ *
+ * foundation.setWriteController(storageWriteController);
+ *
+ * final EmbeddedStorageManager storage = foundation.start();
+ * }
+ * </pre>
+ *
+ */
+public class StorageWriteControllerReadOnlyMode implements StorageWriteController
+{
+	private final static Logger logger = Logging.getLogger(StorageWriteController.class);
+
+	///////////////////////////////////////////////////////////////////////////
+	// instance fields //
+	////////////////////
+
+	private WriteController writeController;
+	private final WriteController defaultController;
+	private final WriteController readOnlyController;
+
+
+	///////////////////////////////////////////////////////////////////////////
+	// constructors //
+	/////////////////
+
+	/**
+	 * Create a new instance of a StorageWriteControllerReadOnlyMode.
+	 * The constructed instance will have the read only mode ENABLED.
+	 * 
+	 * @param writeController the {@link StorageWriteController} instance
+	 * that is used if the read only mode is disabled.
+	 */
+	public StorageWriteControllerReadOnlyMode(final WriteController writeController)
+	{
+		super();
+		this.defaultController = writeController;
+		this.readOnlyController = WriteController.Disabled();
+		this.writeController = this.readOnlyController;
+
+		logger.info("Created SwitchableStorageWriteController with Storage read-only mode enabled: {}!",
+			this.writeController == this.readOnlyController
+		);
+	}
+
+
+	///////////////////////////////////////////////////////////////////////////
+	// methods //
+	////////////
+
+	public void enableReadOnly(final boolean enableReadOnly)
+	{
+		if(enableReadOnly)
+		{
+			this.writeController = this.readOnlyController;
+		}
+		else
+		{
+			this.writeController = this.defaultController;
+		}
+
+		logger.info("Read-only mode enabled: {}", this.writeController == this.readOnlyController);
+	}
+
+	public boolean readOnlyEnabled()
+	{
+		return this.writeController == this.readOnlyController;
+	}
+
+	@Override
+	public void validateIsWritable()
+	{
+		this.writeController.validateIsWritable();
+	}
+
+	@Override
+	public boolean isWritable()
+	{
+		return this.writeController.isWritable();
+	}
+
+	@Override
+	public boolean isFileCleanupEnabled()
+	{
+		return this.writeController.isWritable();
+	}
+
+	@Override
+	public boolean isBackupEnabled()
+	{
+		//must return true to start the backup handler even if writing
+		//is not enabled during startup!
+		return this.defaultController.isWritable();
+	}
+
+	@Override
+	public boolean isDeletionDirectoryEnabled()
+	{
+		return this.writeController.isWritable();
+	}
+
+	@Override
+	public boolean isFileDeletionEnabled()
+	{
+		return this.writeController.isWritable();
+	}
+
+}