Overview

In Order to get a consistent string representation of the classes used in a project, we can

• use a toString generator, e.g eclipse ‘Generate toString()…’
• use a builder mechanism in the toString() implementation.

From ToStringBuilder javadoc

• allowing field names
• handling all types consistently
• handling nulls consistently
• outputting arrays and multi-dimensional arrays
• enabling the detail level to be controlled for Objects and Collections
• handling class hierarchies

How to use

1. Create new ToStringBuilder with the current object: new ToStringBuilder(this)
2. Append items with append(...) methods
3. use toString()

class Person {
        String name ="Joe";
        int age = 22;
        boolean smoker= true;

        @Override
        public String toString() {
            return new ToStringBuilder(this)
                    .append("name", name)
                    .append("age", age)
                    .append("smoker", smoker).toString();
        }
    }

outputs

Person@d2cc05a[name=Joe,age=22,smoker=true]

The ToStringStyle class

The ToStringStyle class controls String formatting for ToStringBuilder. There are some predefined styles as constants in the ToStringStyle class:

• DEFAULT_STYLE
• MULTI_LINE_STYLE
• NO_FIELD_NAMES_STYLE
• SHORT_PREFIX_STYLE
• SIMPLE_STYLE

By subclassing the ToStringStyle class one can define custom styles.

References

http://commons.apache.org/proper/commons-lang/javadocs/api-release/org/apache/commons/lang3/builder/ToStringBuilder.html