storm-compatibility/src/java/org/apache/storm/tuple/Tuple.java

/**
 * 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.storm.tuple;

import java.util.List;

/**
 * The tuple is the main data structure in Storm. A tuple is a named list of values,
 * where each value can be any type. Tuples are dynamically typed -- the types of the fields
 * do not need to be declared. Tuples have helper methods like getInteger and getString
 * to get field values without having to cast the result.
 * <p>
 * Storm needs to know how to serialize all the values in a tuple. By default, Storm
 * knows how to serialize the primitive types, strings, and byte arrays. If you want to
 * use another type, you'll need to implement and register a serializer for that type.
 * @see <a href="https://storm.apache.org/documentation/Serialization.html">Storm serialization</a>
 */
public interface Tuple {

  /**
   * Returns the number of fields in this tuple.
   */
  int size();

  /**
   * Returns true if this tuple contains the specified name of the field.
   */
  boolean contains(String field);

  /**
   * Gets the names of the fields in this tuple.
   */
  Fields getFields();

  /**
   *  Returns the position of the specified field in this tuple.
   *
   * @throws IllegalArgumentException - if field does not exist
   */
  int fieldIndex(String field);

  /**
   * Returns a subset of the tuple based on the fields selector.
   */
  List<Object> select(Fields selector);

  /**
   * Gets the field at position i in the tuple. Returns object since tuples are dynamically typed.
   *
   * @throws IndexOutOfBoundsException - if the index is out of range `(index &lt; 0 || index &gt;= size())`
   */
  Object getValue(int i);

  /**
   * Returns the String at position i in the tuple.
   *
   * @throws ClassCastException If that field is not a String
   * @throws IndexOutOfBoundsException - if the index is out of range `(index &lt; 0 || index &gt;= size())`
   */
  String getString(int i);

  /**
   * Returns the Integer at position i in the tuple.
   *
   * @throws ClassCastException If that field is not a Integer
   * @throws IndexOutOfBoundsException - if the index is out of range `(index &lt; 0 || index &gt;= size())`
   */
  Integer getInteger(int i);

  /**
   * Returns the Long at position i in the tuple.
   *
   * @throws ClassCastException If that field is not a Long
   * @throws IndexOutOfBoundsException - if the index is out of range `(index &lt; 0 || index &gt;= size())`
   */
  Long getLong(int i);

  /**
   * Returns the Boolean at position i in the tuple.
   *
   * @throws ClassCastException If that field is not a Boolean
   * @throws IndexOutOfBoundsException - if the index is out of range `(index &lt; 0 || index &gt;= size())`
   */
  Boolean getBoolean(int i);

  /**
   * Returns the Short at position i in the tuple.
   *
   * @throws ClassCastException If that field is not a Short
   * @throws IndexOutOfBoundsException - if the index is out of range `(index &lt; 0 || index &gt;= size())`
   */
  Short getShort(int i);

  /**
   * Returns the Byte at position i in the tuple.
   *
   * @throws ClassCastException If that field is not a Byte
   * @throws IndexOutOfBoundsException - if the index is out of range `(index &lt; 0 || index &gt;= size())`
   */
  Byte getByte(int i);

  /**
   * Returns the Double at position i in the tuple.
   *
   * @throws ClassCastException If that field is not a Double
   * @throws IndexOutOfBoundsException - if the index is out of range `(index &lt; 0 || index &gt;= size())`
   */
  Double getDouble(int i);

  /**
   * Returns the Float at position i in the tuple.
   *
   * @throws ClassCastException If that field is not a Float
   * @throws IndexOutOfBoundsException - if the index is out of range `(index &lt; 0 || index &gt;= size())`
   */
  Float getFloat(int i);

  /**
   * Returns the byte array at position i in the tuple.
   *
   * @throws ClassCastException If that field is not a byte array
   * @throws IndexOutOfBoundsException - if the index is out of range `(index &lt; 0 || index &gt;= size())`
   */
  byte[] getBinary(int i);

  /**
   * Gets the field with a specific name. Returns object since tuples are dynamically typed.
   *
   * @throws IllegalArgumentException - if field does not exist
   */
  Object getValueByField(String field);

  /**
   * Gets the String field with a specific name.
   *
   * @throws ClassCastException If that field is not a String
   * @throws IllegalArgumentException - if field does not exist
   */
  String getStringByField(String field);

  /**
   * Gets the Integer field with a specific name.
   *
   * @throws ClassCastException If that field is not an Integer
   * @throws IllegalArgumentException - if field does not exist
   */
  Integer getIntegerByField(String field);

  /**
   * Gets the Long field with a specific name.
   *
   * @throws ClassCastException If that field is not a Long
   * @throws IllegalArgumentException - if field does not exist
   */
  Long getLongByField(String field);

  /**
   * Gets the Boolean field with a specific name.
   *
   * @throws ClassCastException If that field is not a Boolean
   * @throws IllegalArgumentException - if field does not exist
   */
  Boolean getBooleanByField(String field);

  /**
   * Gets the Short field with a specific name.
   *
   * @throws ClassCastException If that field is not a Short
   * @throws IllegalArgumentException - if field does not exist
   */
  Short getShortByField(String field);

  /**
   * Gets the Byte field with a specific name.
   *
   * @throws ClassCastException If that field is not a Byte
   * @throws IllegalArgumentException - if field does not exist
   */
  Byte getByteByField(String field);

  /**
   * Gets the Double field with a specific name.
   *
   * @throws ClassCastException If that field is not a Double
   * @throws IllegalArgumentException - if field does not exist
   */
  Double getDoubleByField(String field);

  /**
   * Gets the Float field with a specific name.
   *
   * @throws ClassCastException If that field is not a Float
   * @throws IllegalArgumentException - if field does not exist
   */
  Float getFloatByField(String field);

  /**
   * Gets the Byte array field with a specific name.
   *
   * @throws ClassCastException If that field is not a byte array
   * @throws IllegalArgumentException - if field does not exist
   */
  byte[] getBinaryByField(String field);

  /**
   * Gets all the values in this tuple.
   */
  List<Object> getValues();


  /**
   * Returns the global stream id (component + stream) of this tuple.
   */
    /*
    TODO:- One can get this using getSourceStreamId and getSourceComponent
     GlobalStreamId getSourceGlobalStreamid();
    */

  /**
   * Gets the id of the component that created this tuple.
   */
  String getSourceComponent();

  /**
   * Gets the id of the task that created this tuple.
   */
  int getSourceTask();

  /**
   * Gets the id of the stream that this tuple was emitted to.
   */
  String getSourceStreamId();

  /**
   * Gets the message id that associated with this tuple.
   */
    /*
    TODO:- does anyone use this
     MessageId getMessageId();
    */

  /**
   * Resets the tuple values to null
   * TODO:- Is this needed
   */
  void resetValues();
}