Use BufferedReader::lines

Description

Java 8 introduced BufferedReader::lines (opens new window) to generate a stream of elements representing lines in the BufferedReader. This rule, replaces While-Loops and For-Loops that are using BufferedReader::readLine to iterate through lines of a file by a stream generated with BufferedReader::lines.

Benefits

Using streams instead of loops improves the readability and makes the code more compact.

Tags

Tags

Java 8, Lambda, Loop, Old Language Constructs, IO Operations, Marker

Code Changes

While Loops

Pre

try (BufferedReader bufferedReader = new BufferedReader(new FileReader("file.name.txt"))) {			
    String line;
    while((line = bufferedReader.readLine()) != null) {
        consume(line);
    }
}

Post

try (BufferedReader bufferedReader = new BufferedReader(new FileReader("file.name.txt"))) {			
    bufferedReader.lines().forEach(line -> {
        consume(line);
    });
}

For Loops with initializer

Pre

try (BufferedReader bufferedReader = new BufferedReader(new FileReader("file.name.txt"))) {			
    for(String line; (line = bufferedReader.readLine()) != null;) {
        consume(line);
    }
}

Post

try (BufferedReader bufferedReader = new BufferedReader(new FileReader("file.name.txt"))) {			
    bufferedReader.lines().forEach(line -> {
        consume(line);
    });
}

For Loops without initializer

Pre

try (BufferedReader bufferedReader = new BufferedReader(new FileReader("file.name.txt"))) {			
    String line;
    for(; (line = bufferedReader.readLine()) != null;) {
        consume(line);
    }
}

Post

try (BufferedReader bufferedReader = new BufferedReader(new FileReader("file.name.txt"))) {			
    bufferedReader.lines().forEach(line -> {
        consume(line);
    });
}

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Properties

Property	Value
Rule ID	BufferedReaderLines
First seen in jSparrow version	3.3.0
Minimum Java version	8
Remediation cost	5 min