Typical Application Scenario

Updated on 2022-09-14 GMT+08:00

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A typical scenario can help you quickly learn and master the Storm topology structure and Spout/Bolt development process.

Scenario Description

Service processing of a dynamic word counting system is described as follows. The data source is a logical unit that produces random text continuously.

The data source continuously sends random text, such as "apple orange apple", to the text splitting logic.
The word splitting logic splits each text entry sent by the data source by space, such as "apple", "orange", "apple", and then sends each word to the word counting logic.
The word counting logic increases the number of times that a specific word occurs by one when receiving the word, and prints the real-time results. For example:
- apple: 1
- orange: 1
- apple: 2

Function Description

Table 1 describes the procedure for a user to develop an application to calculate the number of times that each word appears in random text.

**Table 1** Functions to be developed
No.	Step	Sample Code
1	Create a Spout to generate random text.	For details, see Creating a Spout.
2	Create a Bolt to split the random text into words.	For details, see Creating a Bolt.
3	Create a Blot to calculate the number of times that each word appears.	For details, see Creating a Bolt.
4	Create a topology.	For details, see Creating a Topology.

For details about certain code, see Creating a Spout, Creating a Bolt, and Creating a Topology. For details about complete code, see the Storm-examples project.

Parent topic: Application Development

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