Coding guidelines

Suggested coding guidelines

1. Indentation: suggest to use 4 spaces; 2 spaces works as well – but be consistent! No tabs please!
2. Spaces:
1. a single space before “(“, “{“
2. a single space after “)”
3. a single space around operators
4. Example: “if (a == b && x != y) {“; avoid “if(a==b&&x!=y){“
3. Blocks: “{“, at the end of the line that starts the block, end the block with “}” in a separate line
4. Statements: earlier restrictions on line length (of 80/132) were likely for printing of the code on paper. Most of us shouldn’t be printing source code on paper now. So, a statement need not be broken into multiple lines – even if it is few hundred characters long.
5. Class member declaration in the following order:

1. static members: public, protected, private; within each accessor, ‘final’ members precede non-final
2. instance members: public, protected, private; within each accessor, ‘final’ members precede non-final
3. Vertically align start of: typeName, variableName, assignment operator
4. methods: public, protected, private; within each accessor, static methods precede non-static
5. methods: all constructors immediately after ‘public static’ methods
6. methods: all getters/setters immediately after constructors
7. methods: all @Override methods immediately after getter/setters
8. methods: use a consistent name for variable holding the return value. Suggested name ‘ret’
9. methods: use a single return for each method (as much as possible)
10. methods: avoid methods with large number of lines; suggested length 24 (from good old days!)
11. Blank line before and after each ‘for/while/do/if-else’ block
12. Blank line after each variable declaration block
13. Separate assignment lines from the rest

Here is a sample code to demonstrate above guidelines:

class MyClass {
    public static final String CONFIG_INDEX_TYPE           = "index.type";
    public static final String CONFIG_INDEX_TYPE_DEF_VALUE = "solr";

    private static final Logger LOG = LoggerFactory.getLogger(MyClass.class);

    protected final String id;

    protected       String updatedBy;

    private final String name;

    private       int    count;

    public static void main(String[] args) {

        // ...

    }

    public MyClass(String name) {

        this.name = name;

        init();

    }

    public String getId() { return id; }

    public String getUpdatedBy() { return updatedBy; }

    public void setUpdatedBy(String updatedBy) { this.updatedBy = updatedBy; }

    public boolean doWork() {

        boolean ret = true;

        for (int i = 0; i < count; i++) {

            if (count > 0 && count % 1000) {

                LOG.info(...);

            }

            test();

        }

        return ret;

    }

    private void init() {

        this.count = 0;

        test();

        // ...

    }
}