| /* |
| * 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.samza.system.descriptors; |
| |
| import com.google.common.base.Preconditions; |
| |
| import java.util.Collections; |
| import java.util.HashMap; |
| import java.util.Map; |
| import java.util.Optional; |
| import java.util.regex.Pattern; |
| import org.apache.commons.lang3.StringUtils; |
| import org.apache.samza.serializers.Serde; |
| |
| /** |
| * A {@link StreamDescriptor} can be used for specifying Samza and system-specific properties of input/output streams. |
| * <p> |
| * Stream properties provided in configuration override corresponding properties specified using a descriptors. |
| * <p> |
| * This is the base descriptor for an input/output stream. Use a system-specific input/output descriptor |
| * (e.g. KafkaInputDescriptor) obtained from its system descriptor (e.g. KafkaSystemDescriptor) if one is available. |
| * Otherwise use the {@link GenericInputDescriptor} and {@link GenericOutputDescriptor} obtained from a |
| * {@link GenericSystemDescriptor}. |
| * |
| * @param <StreamMessageType> type of messages in this stream. |
| * @param <SubClass> type of the concrete sub-class |
| */ |
| public abstract class StreamDescriptor<StreamMessageType, SubClass extends StreamDescriptor<StreamMessageType, SubClass>> { |
| private static final String SYSTEM_CONFIG_KEY = "streams.%s.samza.system"; |
| private static final String PHYSICAL_NAME_CONFIG_KEY = "streams.%s.samza.physical.name"; |
| private static final String STREAM_CONFIGS_CONFIG_KEY = "streams.%s.%s"; |
| private static final Pattern STREAM_ID_PATTERN = Pattern.compile("[\\d\\w-_]+"); |
| |
| private final String streamId; |
| private final Serde serde; |
| private final SystemDescriptor systemDescriptor; |
| |
| private final Map<String, String> streamConfigs = new HashMap<>(); |
| private Optional<String> physicalNameOptional = Optional.empty(); |
| |
| /** |
| * Constructs a {@link StreamDescriptor} instance. |
| * |
| * @param streamId id of the stream |
| * @param serde serde for messages in the stream |
| * @param systemDescriptor system descriptor this stream descriptor was obtained from |
| */ |
| StreamDescriptor(String streamId, Serde serde, SystemDescriptor systemDescriptor) { |
| Preconditions.checkArgument(systemDescriptor != null, |
| String.format("SystemDescriptor must not be null. streamId: %s", streamId)); |
| String systemName = systemDescriptor.getSystemName(); |
| Preconditions.checkState(isValidStreamId(streamId), |
| String.format("streamId must be non-empty and must not contain spaces or special characters. " + |
| "streamId: %s, systemName: %s", streamId, systemName)); |
| Preconditions.checkArgument(serde != null, |
| String.format("Serde must not be null. streamId: %s systemName: %s", streamId, systemName)); |
| this.streamId = streamId; |
| this.serde = serde; |
| this.systemDescriptor = systemDescriptor; |
| } |
| |
| /** |
| * The physical name of the stream on the system on which this stream will be accessed. |
| * This is opposed to the {@code streamId} which is the logical name that Samza uses to identify the stream. |
| * <p> |
| * A physical name could be a Kafka topic name, an HDFS file URN, or any other system-specific identifier. |
| * <p> |
| * If not provided, the logical {@code streamId} is used as the physical name. |
| * |
| * @param physicalName physical name for this stream. |
| * @return this stream descriptor. |
| */ |
| public SubClass withPhysicalName(String physicalName) { |
| this.physicalNameOptional = Optional.ofNullable(physicalName); |
| return (SubClass) this; |
| } |
| |
| /** |
| * Additional system-specific properties for this stream. |
| * <p> |
| * These properties are added under the {@code streams.stream-id.*} scope. |
| * |
| * @param streamConfigs system-specific properties for this stream |
| * @return this stream descriptor |
| */ |
| public SubClass withStreamConfigs(Map<String, String> streamConfigs) { |
| this.streamConfigs.putAll(streamConfigs); |
| return (SubClass) this; |
| } |
| |
| public String getStreamId() { |
| return this.streamId; |
| } |
| |
| public String getSystemName() { |
| return this.systemDescriptor.getSystemName(); |
| } |
| |
| public Serde getSerde() { |
| return this.serde; |
| } |
| |
| public SystemDescriptor getSystemDescriptor() { |
| return this.systemDescriptor; |
| } |
| |
| public Optional<String> getPhysicalName() { |
| return physicalNameOptional; |
| } |
| |
| private boolean isValidStreamId(String id) { |
| return StringUtils.isNotBlank(id) && STREAM_ID_PATTERN.matcher(id).matches(); |
| } |
| |
| public Map<String, String> toConfig() { |
| HashMap<String, String> configs = new HashMap<>(); |
| configs.put(String.format(SYSTEM_CONFIG_KEY, streamId), getSystemName()); |
| this.physicalNameOptional.ifPresent(physicalName -> |
| configs.put(String.format(PHYSICAL_NAME_CONFIG_KEY, streamId), physicalName)); |
| this.streamConfigs.forEach((key, value) -> |
| configs.put(String.format(STREAM_CONFIGS_CONFIG_KEY, streamId, key), value)); |
| return Collections.unmodifiableMap(configs); |
| } |
| } |