content: /*
   * 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.kafka.streams.kstream.internals.foreignkeyjoin;
  
  import org.apache.kafka.common.errors.UnsupportedVersionException;
  
  import java.util.Arrays;
  import java.util.Objects;
  
  public class SubscriptionWrapper<KLeft> {
      static final byte VERSION_0 = 0;
      static final byte VERSION_1 = 1;
  
      static final byte CURRENT_VERSION = VERSION_1;
  
      // v0 fields:
      private final long[] hash;
      private final Instruction instruction;
      private final byte version;
      private final KLeft primaryKey;
      // v1 fields:
      private final Integer primaryPartition;
  
      public enum Instruction {
          //Send nothing. Do not propagate.
          DELETE_KEY_NO_PROPAGATE((byte) 0x00),
  
          //Send (k, null)
          DELETE_KEY_AND_PROPAGATE((byte) 0x01),
  
          //(changing foreign key, but FK+Val may not exist)
          //Send (k, fk-val) OR
          //Send (k, null) if fk-val does not exist
          PROPAGATE_NULL_IF_NO_FK_VAL_AVAILABLE((byte) 0x02),
  
          //(first time ever sending key)
          //Send (k, fk-val) only if fk-val exists.
          PROPAGATE_ONLY_IF_FK_VAL_AVAILABLE((byte) 0x03);
  
          private final byte value;
          Instruction(final byte value) {
              this.value = value;
          }
  
          public byte value() {
              return value;
          }
  
          public static Instruction fromValue(final byte value) {
              for (final Instruction i: values()) {
                  if (i.value == value) {
                      return i;
                  }
              }
              throw new IllegalArgumentException("Unknown instruction byte value = " + value);
          }
      }
  
      public SubscriptionWrapper(final long[] hash, final Instruction instruction, final KLeft primaryKey, final Integer primaryPartition) {
          this(hash, instruction, primaryKey, CURRENT_VERSION, primaryPartition);
      }
  
      public SubscriptionWrapper(final long[] hash, final Instruction instruction, final KLeft primaryKey, final byte version, final Integer primaryPartition) {
          Objects.requireNonNull(instruction, "instruction cannot be null. Required by downstream processor.");
          Objects.requireNonNull(primaryKey, "primaryKey cannot be null. Required by downstream processor.");
          if (version < 0 || version > CURRENT_VERSION) {
              throw new UnsupportedVersionException("SubscriptionWrapper does not support version " + version);
          }
  
          this.instruction = instruction;
          this.hash = hash;
          this.primaryKey = primaryKey;
          this.version = version;
          this.primaryPartition = primaryPartition;
      }
  
      public Instruction instruction() {
          return instruction;
      }
  
      public long[] hash() {
          return hash;
      }
  
      public KLeft primaryKey() {
          return primaryKey;
      }
  
      public byte version() {
          return version;
      }
  
      public Integer primaryPartition() {
          return primaryPartition;
      }
  
      @Override
      public String toString() {
          return "SubscriptionWrapper{" +
              "version=" + version +
              ", primaryKey=" + primaryKey +
              ", instruction=" + instruction +
              ", hash=" + Arrays.toString(hash) +
              ", primaryPartition=" + primaryPartition +
              '}';
      }
  
      @Override
      public boolean equals(final Object o) {
          if (this == o) {
              return true;
          }
          if (o == null || getClass() != o.getClass()) {
              return false;
          }
          final SubscriptionWrapper<?> that = (SubscriptionWrapper<?>) o;
          return version == that.version && Arrays.equals(hash, that.hash)
              && instruction == that.instruction && Objects.equals(primaryKey, that.primaryKey)
              && Objects.equals(primaryPartition, that.primaryPartition);
      }
  
      @Override
      public int hashCode() {
          int result = Objects.hash(instruction, version, primaryKey, primaryPartition);
          result = 31 * result + Arrays.hashCode(hash);
          return result;
      }
  }
  