| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you 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 org.apache.cassandra.schema; |
| |
| import java.time.Duration; |
| import java.util.UUID; |
| import java.util.function.BiConsumer; |
| |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| |
| import org.apache.cassandra.schema.SchemaTransformation.SchemaTransformationResult; |
| import org.apache.cassandra.utils.ByteArrayUtil; |
| import org.apache.cassandra.utils.concurrent.Awaitable; |
| import org.apache.cassandra.utils.concurrent.ImmediateFuture; |
| |
| /** |
| * Update handler which works only in memory. It does not load or save the schema anywhere. It is used in client mode |
| * applications. |
| */ |
| public class OfflineSchemaUpdateHandler implements SchemaUpdateHandler |
| { |
| private static final Logger logger = LoggerFactory.getLogger(OfflineSchemaUpdateHandler.class); |
| |
| private final BiConsumer<SchemaTransformationResult, Boolean> updateCallback; |
| |
| private volatile DistributedSchema schema = DistributedSchema.EMPTY; |
| |
| public OfflineSchemaUpdateHandler(BiConsumer<SchemaTransformationResult, Boolean> updateCallback) |
| { |
| this.updateCallback = updateCallback; |
| } |
| |
| @Override |
| public void start() |
| { |
| // no-op |
| } |
| |
| @Override |
| public boolean waitUntilReady(Duration timeout) |
| { |
| return true; |
| } |
| |
| @Override |
| public synchronized SchemaTransformationResult apply(SchemaTransformation transformation, boolean local) |
| { |
| DistributedSchema before = schema; |
| Keyspaces afterKeyspaces = transformation.apply(before.getKeyspaces()); |
| Keyspaces.KeyspacesDiff diff = Keyspaces.diff(before.getKeyspaces(), afterKeyspaces); |
| |
| if (diff.isEmpty()) |
| return new SchemaTransformationResult(before, before, diff); |
| |
| DistributedSchema after = new DistributedSchema(afterKeyspaces, UUID.nameUUIDFromBytes(ByteArrayUtil.bytes(afterKeyspaces.hashCode()))); |
| SchemaTransformationResult update = new SchemaTransformationResult(before, after, diff); |
| this.schema = after; |
| logger.debug("Schema updated: {}", update); |
| updateCallback.accept(update, true); |
| |
| return update; |
| } |
| |
| @Override |
| public void reset(boolean local) |
| { |
| if (!local) |
| throw new UnsupportedOperationException(); |
| |
| apply(ignored -> SchemaKeyspace.fetchNonSystemKeyspaces(), local); |
| } |
| |
| @Override |
| public synchronized Awaitable clear() |
| { |
| this.schema = DistributedSchema.EMPTY; |
| return ImmediateFuture.success(true); |
| } |
| } |