ConsoleTable

Sometimes one needs to display tabular data from a console java app. The Clojure guys have print-table (https://clojuredocs.org/clojure.pprint/print-table). Now you have one in Java too.

As of today the class supports: lists or arrays of scalars (Strings, ints...), Maps, Lists or arrays of Objects It was developed in a couple of hours for a q&d project, reusing old code of mine, take it as-is.

It requires Java 8 but could easily be retrofitted for Java 7 or 6.

How it works

ConsoleTable is a simple class remotely inspired by Swing's Tables which enables you to display the contents of tabular data in a log or on the console.

SimpleConsoleTable is one implementation that uses introspection on the input data. You may add more implementations.

The #toString() method triggers rendering, so you may directly use a ConsoleTable instance in a Logger or System.out/err

Output

List of Objects discovered via introspection.

Column headers are the objects actual property names.
Default renderer is String.ValueOf()
Default alignment is right and null values are printed as empty Strings also by default.

|=======================================================|
|  BirthDate |     FirstName |  LastName | UsingWindows |
|=======================================================|
| 1969-11-15 |       Lisa T. |        Su |         true |
|-------------------------------------------------------|
|            |               |           |              |
|-------------------------------------------------------|
| 1955-10-28 | William Henry | Gates III |         true |
|-------------------------------------------------------|
| 1955-02-24 |        Steven |      Jobs |        false |
|=======================================================|

Custom table based on above objects

"First Name "and "Last Name" are right-aligned and null values should be printed as "-"
"Birth Date" is left-aligned, format is dd MMM yyyy in the current locale and null values should be printed as "N/A"
"Born during Fall" is centered, format is "Yes"/"No" and null values become "?"

|==============================================================|
|    First Name | Last Name | Birth Date    | Born during Fall |
|==============================================================|
|       Lisa T. |        Su | 15 nov. 1969  |       Yes        |
|--------------------------------------------------------------|
|             - |         - | N/A           |        ?         |
|--------------------------------------------------------------|
| William Henry | Gates III | 28 oct. 1955  |       Yes        |
|--------------------------------------------------------------|
|        Steven |      Jobs | 24 févr. 1955 |        No        |
|==============================================================|

List<String>

{"Hello", "how", "are", null, "you"}
Default column header is the scalar's simple class name

|========|
| String |
|========|
|  Hello |
|--------|
|    how |
|--------|
|    are |
|--------|
|        |
|--------|
|   you? |
|========|

Array of int/Integers

{null, 123, 456, 789}

|=========|
| Integer |
|=========|
|         |
|---------|
|     123 |
|---------|
|     456 |
|---------|
|     789 |
|=========|

Map<String, Integer>

Default column headers are found via introspection.

|=======================|
|           Key | Value |
|=======================|
|       Lisa T. |    47 |
|-----------------------|
| William Henry |    61 |
|-----------------------|
|        Steven |       |
|=======================|

Object[][]

No header to infer.
"N/A" should be printed for null values.

|==========================================|
|       Lisa T. |        Su | 1969 |  true |
|------------------------------------------|
| William Henry | Gates III |  N/A |   N/A |
|------------------------------------------|
|        Steven |      Jobs | 1955 | false |
|==========================================|

Note the table can manage with arrays of different sizes.

Empty List/Array

|==|
|==|

TODO

• configurable table borders