org.apache.storm.tuple.Tuple Maven / Gradle / Ivy
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* 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.
*
* 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 Storm serialization
*/
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