| /* |
| * 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; |
| |
| import java.util.Collections; |
| import java.util.Map; |
| |
| import org.apache.samza.Partition; |
| import org.apache.samza.SamzaException; |
| |
| /** |
| * SystemAdmins use this class to return useful metadata about a stream's offset |
| * and partition information. |
| */ |
| public class SystemStreamMetadata { |
| private final String streamName; |
| private final Map<Partition, SystemStreamPartitionMetadata> partitionMetadata; |
| |
| public SystemStreamMetadata(String streamName, Map<Partition, SystemStreamPartitionMetadata> partitionMetadata) { |
| this.streamName = streamName; |
| this.partitionMetadata = partitionMetadata; |
| } |
| |
| /** |
| * @return The stream name that's associated with the metadata contained in an |
| * instance of this class. |
| */ |
| public String getStreamName() { |
| return streamName; |
| } |
| |
| /** |
| * @return A map of SystemStreamPartitionMetadata that includes offset |
| * information for each partition. |
| */ |
| public Map<Partition, SystemStreamPartitionMetadata> getSystemStreamPartitionMetadata() { |
| return Collections.unmodifiableMap(partitionMetadata); |
| } |
| |
| @Override |
| public int hashCode() { |
| final int prime = 31; |
| int result = 1; |
| result = prime * result + ((partitionMetadata == null) ? 0 : partitionMetadata.hashCode()); |
| result = prime * result + ((streamName == null) ? 0 : streamName.hashCode()); |
| return result; |
| } |
| |
| @Override |
| public boolean equals(Object obj) { |
| if (this == obj) |
| return true; |
| if (obj == null) |
| return false; |
| if (getClass() != obj.getClass()) |
| return false; |
| SystemStreamMetadata other = (SystemStreamMetadata) obj; |
| if (partitionMetadata == null) { |
| if (other.partitionMetadata != null) |
| return false; |
| } else if (!partitionMetadata.equals(other.partitionMetadata)) |
| return false; |
| if (streamName == null) { |
| if (other.streamName != null) |
| return false; |
| } else if (!streamName.equals(other.streamName)) |
| return false; |
| return true; |
| } |
| |
| @Override |
| public String toString() { |
| return "SystemStreamMetadata [streamName=" + streamName + ", partitionMetadata=" + partitionMetadata + "]"; |
| } |
| |
| /** |
| * Provides offset information for a given SystemStreamPartition. This |
| * currently only includes offset information. |
| */ |
| public static class SystemStreamPartitionMetadata { |
| private final String oldestOffset; |
| private final String newestOffset; |
| private final String upcomingOffset; |
| |
| public SystemStreamPartitionMetadata(String oldestOffset, String newestOffset, String upcomingOffset) { |
| this.oldestOffset = oldestOffset; |
| this.newestOffset = newestOffset; |
| this.upcomingOffset = upcomingOffset; |
| } |
| |
| /** |
| * @return The oldest offset that still exists in the stream for the |
| * partition given. If a partition has two messages with offsets 0 |
| * and 1, respectively, then this method would return 0 for the |
| * oldest offset. This offset is useful when one wishes to read all |
| * messages in a stream from the very beginning. A null value means |
| * the stream is empty. |
| */ |
| public String getOldestOffset() { |
| return oldestOffset; |
| } |
| |
| /** |
| * @return The newest offset that exists in the stream for the partition |
| * given. If a partition has two messages with offsets 0 and 1, |
| * respectively, then this method would return 1 for the newest |
| * offset. This offset is useful when one wishes to see if all |
| * messages have been read from a stream (offset of last message |
| * read == newest offset). A null value means the stream is empty. |
| */ |
| public String getNewestOffset() { |
| return newestOffset; |
| } |
| |
| /** |
| * @return The offset that represents the next message to be written in the |
| * stream for the partition given. If a partition has two messages |
| * with offsets 0 and 1, respectively, then this method would return |
| * 2 for the upcoming offset. This offset is useful when one wishes |
| * to pick up reading at the very end of a stream. A null value |
| * means the stream is empty. |
| */ |
| public String getUpcomingOffset() { |
| return upcomingOffset; |
| } |
| |
| /** |
| * @param offsetType |
| * The type of offset to get. Either oldest, newest, or upcoming. |
| * @return The corresponding offset for the offset type requested. |
| */ |
| public String getOffset(OffsetType offsetType) { |
| if (offsetType.equals(OffsetType.OLDEST)) { |
| return getOldestOffset(); |
| } else if (offsetType.equals(OffsetType.NEWEST)) { |
| return getNewestOffset(); |
| } else if (offsetType.equals(OffsetType.UPCOMING)) { |
| return getUpcomingOffset(); |
| } else { |
| throw new SamzaException("Invalid offset type defined " + offsetType + "."); |
| } |
| } |
| |
| @Override |
| public int hashCode() { |
| final int prime = 31; |
| int result = 1; |
| result = prime * result + ((newestOffset == null) ? 0 : newestOffset.hashCode()); |
| result = prime * result + ((oldestOffset == null) ? 0 : oldestOffset.hashCode()); |
| result = prime * result + ((upcomingOffset == null) ? 0 : upcomingOffset.hashCode()); |
| return result; |
| } |
| |
| @Override |
| public boolean equals(Object obj) { |
| if (this == obj) |
| return true; |
| if (obj == null) |
| return false; |
| if (getClass() != obj.getClass()) |
| return false; |
| SystemStreamPartitionMetadata other = (SystemStreamPartitionMetadata) obj; |
| if (newestOffset == null) { |
| if (other.newestOffset != null) |
| return false; |
| } else if (!newestOffset.equals(other.newestOffset)) |
| return false; |
| if (oldestOffset == null) { |
| if (other.oldestOffset != null) |
| return false; |
| } else if (!oldestOffset.equals(other.oldestOffset)) |
| return false; |
| if (upcomingOffset == null) { |
| if (other.upcomingOffset != null) |
| return false; |
| } else if (!upcomingOffset.equals(other.upcomingOffset)) |
| return false; |
| return true; |
| } |
| |
| @Override |
| public String toString() { |
| return "SystemStreamPartitionMetadata [oldestOffset=" + oldestOffset + ", newestOffset=" + newestOffset + ", upcomingOffset=" + upcomingOffset + "]"; |
| } |
| } |
| |
| /** |
| * OffsetType is an enum used to define which offset should be used when |
| * reading from a SystemStreamPartition for the first time. |
| */ |
| public enum OffsetType { |
| |
| /** |
| * Signals the offset of the oldest message in a SystemStreamPartition. |
| */ |
| OLDEST("oldest"), |
| |
| /** |
| * Signals the offset of the newest message in a SystemStreamPartition. |
| */ |
| NEWEST("newest"), |
| |
| /** |
| * Signals the offset of the next message to be written into a |
| * SystemStreamPartition. If the offset of the most recent message written |
| * to a SystemStreamPartition is 7, then upcoming would signal offset 8 |
| * (assuming the offsets were incremental). |
| */ |
| UPCOMING("upcoming"); |
| |
| private final String offsetType; |
| |
| private OffsetType(String offsetType) { |
| this.offsetType = offsetType; |
| } |
| } |
| } |