WordCount | Different programs

WordCount is a Java library. WordCount has no bugs, it has no vulnerabilities and it has low support. However WordCount build file is not available. You can download it from GitHub.

a. OneWordCount.java This is the driver class. In the driver class, a Job instance in initialized and is configured. Various facets of the job, such as the input/output paths (passed via the command line), key/value types, input/output formats etc. are configured in the Job Configuration. It then calls the waitForCompletion to submit the job and monitor its progress. b. OneWordMapper.java This class is the mapper class. It receives a key and single line as value in input. The line is then tokenized into words and for each word a key/value pair of the form is set in the Job Context. c. SumReducer.java This class is the reducer class. It receives a key- a single word and a list of counts for that word. It will then sum up the counts to produce the final output key/value pair as . a. DoubleWordCount.java This program is same as OneWordCount.java which is the driver class for the Double Word Count Job. b. DoubleWordMapper.java This class is the mapper class for Double Word Count Job. It differs from One Word Mapper in that it outputs a key/value pair of the form . The previous token is initialized before the while loop to the first word for the line. For every next word in the while loop, we form a new key – ‘previous token space current token’. And this key is set with the value 1 in the context. The current token now becomes the previous token. c. SumReducer.java This class is similar to One Word Count Job reducer class and it just sums up the counts for the double word pairs. a. WordCount.java This is the main class. It implements Tool interface to handle custom arguments to the program. The run method is called by the ToolRunner with the command-line arguments. The run method loops through the commandline arguments to find the location for the small word list file. It then sets this file for distributed caching in the job context by calling addCacheFile method on the job instance. b. WordMapper.java This class is the mapper class. In the setup method of the Mapper, the location of the cached file in the local disk of the task node is fetched using the method getLocalCacheFiles on the context object. The file is read from this location by the parseSearchFile method and a list of words present in the file is stored in an array. The map method then uses this list of words to output count of only those words present in this list. c. SumReducer.java This is the reducer class and is similar to the One Word Count Job class.