PrettyJsonWriter

For this homework, you will create a class that outputs various collections as "pretty" JSON objects or arrays to file. Use 2 space characters for each level of indentation and use line separators between elements. For example, a "pretty" JSON array looks like:

[
  1,
  2,
  3
]

Note that there is no comma after the last element in the array. Objects look like:

{
  "ant": 1,
  "bat": 2,
  "cat": 3
}

Note that strings and keys are always in " quotation marks, but numbers are not. A nested object looks like:

{
  "ant": [
    1
  ],
  "bat": [
    1,
    2
  ],
  "cat": [
    1,
    2,
    3
  ]
}

The examples here happen to be sorted, but that is not necessary for JSON output.

Use UTF8 when writing your files. See the Javadoc comments in the template code for additional details.

Design

It is possible to pass the tests with a less-than ideal implementation. Focus first on passing the tests by the deadline. AFTER you have working implementations, try to improve your solution as follows:

• Do not use String replacement or concatenation. Use iteration instead.

• Reuse methods as much as possible. You should be able to use asArray within your asNestedArray method.

• Try to avoid needing extra logic within your loops. For example, avoid testing every element to see if it is the last one.

• Try to reduce repeated code. If you notice you had to copy and paste a chunk of code, it might be a good to use move that logic into a method.

The above does not need to be completed by the homework deadline, but will be required to pass code reviews for similar functionality in the projects.

Hints

Below are some hints that may help with this homework assignment:

• Eclipse has built-in file comparison functionality. It can show you exactly how your file output differs from the expected output (even if its just a trailing space at the end of a line).

• The general form of each method takes an indentation level, which allows for reusing these methods when creating nested output. The indentation level should be not be applied to the first bracket or brace. Instead, output the inner elements by one more than the provided level, and output the final bracket or brace at the original indentation level.

• If you directly call write() an int or Integer, it will often be seen as a character code. For example, 65 is the character code for A. If you want to actually write the digits 65 to file, convert to a String object first. For example, try running this:

  PrintWriter writer = new PrintWriter(System.out);
  Integer i = 65;
  writer.write(i);
  writer.flush();

  Compare that output to:

  PrintWriter writer = new PrintWriter(System.out);
  Integer i = 65;
  writer.write(i.toString());
  writer.flush();

  Note this is not a problem for most print() and println() methods, so it depends on what you use to write to file.

• The official JSON documentation can be a little difficult to parse. There are many other tutorials out there.

These hints are optional. There may be multiple approaches to solving this homework.

Instructions

Use the "Tasks" view in Eclipse to find the TODO comments for what need to be implemented and the "Javadoc" view to see additional details.

The tests are provided in the src/test/ directory; do not modify any of the files in that directory. Check the run details on GitHub Actions for how many points each test group is worth.

See the Homework Guides for additional details on homework requirements and submission.