org.apache.sis.util.collection

## Class TreeTableFormat

- Object
- - Format
  - - CompoundFormat<T>
    - - TabularFormat<TreeTable>
      - - TreeTableFormat

- All Implemented Interfaces:
    Serializable, Cloneable, Localized

      public class TreeTableFormat
      extends TabularFormat<TreeTable>

  A parser and formatter for `TreeTable` instances. This formatter is given an arbitrary number of `TableColumn`s to use during the formatting. The first column is taken as the node label. If a `TreeTable` is formatted with only that column, then the `String` result is like the following example:

      Node #1
        ├─Node #2
        │   └─Node #4
        └─Node #3

  If the same `TreeTable` is formatted with two columns, then the `String` result is like the following example:

      Node #1……………………… More #1
        ├─Node #2…………… More #2
        │   └─Node #4… More #4
        └─Node #3…………… More #3

  This representation can be printed to the console output (for example) if the stream uses a monospaced font and supports Unicode characters.
  Customization
  Some formatting characteristics (indentation width, column where to draw the vertical line below nodes) can be modified by calls to the setter methods defined in this formatter. In particular, the dots joining the node labels to their values can be specified by the column separator pattern. The default pattern is `"?……[…] "`, which means "If the next value is non-null, then insert the `"……"` string, repeat the `'…'` character as many time as needed (may be zero), and finally insert a space".
  Safety against infinite recursivity
  Some `TreeTable` implementations generate the nodes dynamically as wrappers around Java objects. Such Java objects may contain cyclic associations (A contains B contains C contains A), which result in a tree of infinite depth. Some examples can been found in ISO 19115 metadata. This `TreeTableFormat` class contains a safety against such cycles. The algorithm is based on the assumption that for each node, the values and children are fully determined by the user object, if non-null. Consequently for each node C to be formatted, if the user object of that node is the same instance (in the sense of the `==` operator) than the user object of a parent node A, then the children of the C node will not be formatted.
  Since:
    0.3
  See Also:
    Serialized Form

  Defined in the `sis-utility` module

- - ### Nested Class Summary

    - ### Nested classes/interfaces inherited from class Format

      `Format​.Field`

  - ### Field Summary

    - ### Fields inherited from class TabularFormat

      `beforeFill, columnSeparator, fillCharacter, lineSeparator, omitTrailingNulls`

  - ### Constructor Summary

    Constructors
    Constructor and Description
    `TreeTableFormat(Locale locale, TimeZone timezone)` Creates a new tree table format.

  - ### Method Summary

    All Methods Instance Methods Concrete Methods
    Modifier and Type | Method and Description
    --- | ---
    `TreeTableFormat` | `clone()` Returns a clone of this format.
    `void` | `format(TreeTable tree, Appendable toAppendTo)` Writes a graphical representation of the specified tree table in the given stream or buffer.
    `TableColumn<?>[]` | `getColumns()` Returns the table columns to parse and format, or `null` for the default list of columns.
    `int` | `getIndentation()` Returns the number of spaces to add on the left margin for each indentation level.
    `Class<TreeTable>` | `getValueType()` Returns the type of objects formatted by this class.
    `int` | `getVerticalLinePosition()` Returns the position of the vertical line, relative to the position of the root label.
    `TreeTable` | `parse(CharSequence text, ParsePosition pos)` Creates a tree from the given character sequence, or returns `null` if the given text does not look like a tree for this method.
    `void` | `setColumns(TableColumn<?>... columns)` Sets the table columns to parse and format.
    `void` | `setIndentation(int indentation)` Sets the number of spaces to add on the left margin for each indentation level.
    `void` | `setVerticalLinePosition(int verticalLinePosition)` Sets the position of the vertical line, relative to the position of the root label.

    - ### Methods inherited from class TabularFormat

      `getColumnSeparatorMatcher, getColumnSeparatorPattern, getLineSeparator, setColumnSeparatorPattern, setLineSeparator`

    - ### Methods inherited from class CompoundFormat

      `createFormat, format, getFormat, getLocale, getLocale, getTimeZone, parseObject, parseObject`

    - ### Methods inherited from class Format

      `format, formatToCharacterIterator`

    - ### Methods inherited from class Object

      `equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

- - ### Constructor Detail

    - #### TreeTableFormat

          public TreeTableFormat(Locale locale,
                                 TimeZone timezone)

      Creates a new tree table format.
      Parameters:
        `locale` - the locale to use for numbers, dates and angles formatting, or `null` for the root locale.
        `timezone` - the timezone, or `null` for UTC.

  - ### Method Detail

    - #### getValueType

          public final Class<TreeTable> getValueType()

      Returns the type of objects formatted by this class.
      Specified by:
        `getValueType` in class `CompoundFormat<TreeTable>`
      Returns:
        `TreeTable​.class`

    - #### getColumns

          public TableColumn<?>[] getColumns()

      Returns the table columns to parse and format, or `null` for the default list of columns. The default is:
      - On parsing, a single column containing the node label as a `String`.
      - On formatting, all `TreeTable` columns.
      Returns:
        the table columns to parse and format, or `null` for the default.

    - #### setColumns

          public void setColumns(TableColumn<?>... columns)
                          throws IllegalArgumentException

      Sets the table columns to parse and format. A `null` value means to use the default list of columns, as defined in the `getColumns()` method.
      Parameters:
        `columns` - the table columns to parse and format, or `null` for the default.
      Throws:
        `IllegalArgumentException` - if the given array is empty, contains a null element or a duplicated value.

    - #### getIndentation

          public int getIndentation()

      Returns the number of spaces to add on the left margin for each indentation level. The default value is 4.
      Returns:
        the current indentation.

    - #### setIndentation

          public void setIndentation(int indentation)
                              throws IllegalArgumentException

      Sets the number of spaces to add on the left margin for each indentation level. If the new indentation is smaller than the vertical line position, then the later is also set to the given indentation value.
      Parameters:
        `indentation` - the new indentation.
      Throws:
        `IllegalArgumentException` - if the given value is negative.

    - #### getVerticalLinePosition

          public int getVerticalLinePosition()

      Returns the position of the vertical line, relative to the position of the root label. The default value is 2, which means that the vertical line is drawn below the third letter of the root label.
      Returns:
        the current vertical line position.

    - #### setVerticalLinePosition

          public void setVerticalLinePosition(int verticalLinePosition)
                                       throws IllegalArgumentException

      Sets the position of the vertical line, relative to the position of the root label. The given value can not be greater than the indentation.
      Parameters:
        `verticalLinePosition` - the new vertical line position.
      Throws:
        `IllegalArgumentException` - if the given value is negative or greater than the indentation.

    - #### parse

          public TreeTable parse(CharSequence text,
                                 ParsePosition pos)
                          throws ParseException

      Creates a tree from the given character sequence, or returns `null` if the given text does not look like a tree for this method. This method can parse the trees created by the `format(…)` methods defined in this class.
      Parsing rules
      - Each node shall be represented by a single line made of two parts, in that order:
        1. white spaces and tree drawing characters (`'│'`, `'├'`, `'└'` or `'─'`);
        2. string representations of node values, separated by the colunm separator.
      - The number of spaces and drawing characters before the node values determines the node indentation. This indentation does not need to be a factor of the `getIndentation()` value, but must be consistent across all the parsed tree.
      - The indentation determines the parent of each node.
      - Parsing stops at first empty line (ignoring whitespaces), or at the end of the given text.
      Error index
      If the given text does not seem to be a tree table, then this method returns `null`. Otherwise if parsing started but failed, then:
      - `ParsePosition​.getErrorIndex()` will give the index at the beginning of line or beginning of cell where the error occurred, and
      - `ParseException​.getErrorOffset()` will give either the same value, or a slightly more accurate value inside the cell.
      Specified by:
        `parse` in class `CompoundFormat<TreeTable>`
      Parameters:
        `text` - the character sequence for the tree to parse.
        `pos` - the position where to start the parsing.
      Returns:
        the parsed tree, or `null` if the given character sequence can not be parsed.
      Throws:
        `ParseException` - if an error occurred while parsing a node value.

    - #### format

          public void format(TreeTable tree,
                             Appendable toAppendTo)
                      throws IOException

      Writes a graphical representation of the specified tree table in the given stream or buffer. This method iterates recursively over all children. For each column to format in each node, this method gets a textual representation of the value in that column using the formatter obtained by a call to `CompoundFormat​.getFormat(Class)`.
      Specified by:
        `format` in class `CompoundFormat<TreeTable>`
      Parameters:
        `tree` - the tree to format.
        `toAppendTo` - where to format the tree.
      Throws:
        `IOException` - if an error occurred while writing to the given appendable.
      See Also:
        `TreeTables​.toString(TreeTable)`

    - #### clone

          public TreeTableFormat clone()

      Returns a clone of this format.
      Overrides:
        `clone` in class `TabularFormat<TreeTable>`
      Returns:
        a clone of this format.

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