DataTable (Student Library Documentation)

All Superinterfaces:

Iterable<DataTable.Row>

All Known Implementing Classes:

CSVDataTable
```
public interface DataTable
extends Iterable<DataTable.Row>
```
A database table or spreadsheet-like abstraction that consists of rows, each of which has an unordered collection of columns. Each row has a row number which, by default, is the primary key of the table. Each row's columns contain string values. Each row can be named as desired by the user. The default column names are "0", "1", "2", ....
A primary key for a table is a column where each value uniquely determines the row. For example, if you had a table of grades, the student's name would be the primary key column. The primary key can be set to whichever row is desired, but the column must uniquely identify each row in the table.

The purpose of this class is to actually pull data from the internet for use in the class, however, it also can be used as a table, where one adds, removes, and updates data on one's own. The table updates can be saved when desired.

The following invariants should be maintained for any implementation:
- At the end of each method, the getRow* methods can reference a row by its primary key on the next instruction.
- The table will have data from one data source at a time. In other words, setting the dataset to another source will wipe out the previously held data in the DataTable.
Version:

$Revision: 1.3 $, $Date: 2012/02/29 03:58:16 $

Author:

Matthew Thornton, Last changed by $Author: stedwar2 $

Nested Class Summary

Nested Classes
Modifier and Type	Interface and Description
`static class`	`DataTable.HashedRow` This is a default concrete implementation of the Row interface.
`static interface`	`DataTable.Row` This interface defines the model used for each row in the table.

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method and Description
`void`	`addColumn(String columnName)` This method adds a column to the table.
`void`	`addColumn(String columnName, String defaultValue)` This method adds a column to the table, setting this column to the specified default value in every row.
`void`	`addRow(DataTable.Row row)` This method adds a row to the table.
`double`	`avg(String column)` This method computes the average of a column that has numeric values.
`int`	`colCount()` This method returns the number of columns in the data table.
`void`	`copyRowsFrom(DataTable dataSet)` This method copies an existing DataTable's rows into the DataTable.
`int`	`count(String column, String value)` This method counts the number of rows in the specified column that have the value given by the value parameter.
`List<DataTable.Row>`	`getAllRows()` This method returns a representation of the Data Table.
`String`	`getCell(int row, int column)` This method returns the String value in the table at a specified row/column location.
`String`	`getCell(int row, String column)` This method returns the String value in the table at a specified row/column location.
`String`	`getCell(String row, int column)` This method returns the String value in the table at a specified row/column location.
`String`	`getCell(String row, String column)` This method returns the String value in the table at a specified row/column location.
`List<String>`	`getColumnNames()` This method returns a list of the names of all of the columns of the data table.
`double`	`getDoubleCell(int row, int column)` This method returns the double value in the table at a specified row/column location.
`double`	`getDoubleCell(int row, String column)` This method returns the double value in the table at a specified row/column location.
`double`	`getDoubleCell(String row, int column)` This method returns the double value in the table at a specified row/column location.
`double`	`getDoubleCell(String row, String column)` This method returns the double value in the table at a specified row/column location.
`int`	`getIntCell(int row, int column)` This method returns the int value in the table at a specified row/column location.
`int`	`getIntCell(int row, String column)` This method returns the int value in the table at a specified row/column location.
`int`	`getIntCell(String row, int column)` This method returns the int value in the table at a specified row/column location.
`int`	`getIntCell(String row, String column)` This method returns the int value in the table at a specified row/column location.
`String`	`getPrimaryKey()` This method returns the column name that acts as the primary key for the table.
`DataTable.Row`	`getRow(int row)` This method returns a map that represents the desired row (indicated by the primary key).
`DataTable.Row`	`getRow(String row)` This method returns a Map that represents the desired row.
`double`	`max(String column)` This method computes the maximum value of a column that has numeric values.
`double`	`min(String column)` This method computes the minimum value of a column that has numeric values.
`void`	`remapColumnNames(Map<String,String> columnMap)` This method replaces each column name in the table with a matching key in columnMap with the value of the mapping.
`DataTable.Row`	`removeRow(int row)` This method removes the row identified by row number.
`DataTable.Row`	`removeRow(String row)` This method removes the row (to be determined by the key).
`int`	`rowCount()` This method returns the number of rows in the data table.
`void`	`save(String filename)` This method saves the data table that has been generated/manipulated in the format desired for the implementation of the interface.
`void`	`setCell(int row, int column, double value)` This method allows you to update a desired row and column with new data as a double.
`void`	`setCell(int row, int column, int value)` This method allows you to update a desired row and column with new data as an int.
`void`	`setCell(int row, int column, String value)` This method allows you to update a desired row and column with new data as a String.
`void`	`setCell(int row, String column, double value)` This method allows you to update a desired row and column with new data as a double.
`void`	`setCell(int row, String column, int value)` This method allows you to update a desired row and column with new data as an int.
`void`	`setCell(int row, String column, String value)` This method allows you to update a desired row and column with new data as a String.
`void`	`setCell(String row, int column, double value)` This method allows you to update a desired row and column with new data as a double.
`void`	`setCell(String row, int column, int value)` This method allows you to update a desired row and column with new data as an int.
`void`	`setCell(String row, int column, String value)` This method allows you to update a desired row and column with new data as a String.
`void`	`setCell(String row, String column, double value)` This method allows you to update a desired row and column with new data as a double.
`void`	`setCell(String row, String column, int value)` This method allows you to update a desired row and column with new data as an int.
`void`	`setCell(String row, String column, String value)` This method allows you to update a desired row and column with new data as a String.
`void`	`setColumnNames(List<String> columnNames)` This method sets an arbitrary name for each of the columns in the table.
`void`	`setColumnNames(String... columnNames)` This method sets an arbitrary name for each of the columns in the table.
`void`	`setPrimaryKey(String key)` This method sets the column name that acts as the primary key for the table.

Methods inherited from interface java.lang.Iterable
forEach, iterator, spliterator

- Method Detail
  - rowCount
```
int rowCount()
```
    This method returns the number of rows in the data table.
    
    Returns:
    
    the number of rows in the data table.
  - colCount
```
int colCount()
```
    This method returns the number of columns in the data table.
    
    Returns:
    
    the number of columns in the data table.
  - getCell
```
String getCell(int row,
               String column)
```
    This method returns the String value in the table at a specified row/column location.
    
    Parameters:
    
    row - index of row to retrieve (starting at zero)
    
    column - the name of the desired column
    
    Returns:
    
    the value in that position as a String object
  - getCell
```
String getCell(int row,
               int column)
```
    This method returns the String value in the table at a specified row/column location.
    
    Parameters:
    
    row - index of row to retrieve (starting at zero)
    
    column - index of column to retrieve (starting at zero)
    
    Returns:
    
    the value in that position as a String object
  - getCell
```
String getCell(String row,
               String column)
```
    This method returns the String value in the table at a specified row/column location.
    
    Parameters:
    
    row - primary key of row
    
    column - the name of the desired column
    
    Returns:
    
    the value in that position as a String object
  - getCell
```
String getCell(String row,
               int column)
```
    This method returns the String value in the table at a specified row/column location.
    
    Parameters:
    
    row - primary key of row
    
    column - index of column to retrieve (starting at zero)
    
    Returns:
    
    the value in that position as a String object
  - getIntCell
```
int getIntCell(int row,
               String column)
        throws NumberFormatException
```
    This method returns the int value in the table at a specified row/column location.
    
    Parameters:
    
    row - index of row to retrieve (starting at zero)
    
    column - the name of the desired column
    
    Returns:
    
    the value in that position as an int
    
    Throws:
    
    NumberFormatException - if the cell does not contain an int value.
  - getIntCell
```
int getIntCell(int row,
               int column)
        throws NumberFormatException
```
    This method returns the int value in the table at a specified row/column location.
    
    Parameters:
    
    row - index of row to retrieve (starting at zero)
    
    column - index of column to retrieve (starting at zero)
    
    Returns:
    
    the value in that position as an int
    
    Throws:
    
    NumberFormatException - if the cell does not contain an int value.
  - getIntCell
```
int getIntCell(String row,
               String column)
        throws NumberFormatException
```
    This method returns the int value in the table at a specified row/column location.
    
    Parameters:
    
    row - primary key of row
    
    column - the name of the desired column
    
    Returns:
    
    the value in that position as an int
    
    Throws:
    
    NumberFormatException - if the cell does not contain an int value.
  - getIntCell
```
int getIntCell(String row,
               int column)
        throws NumberFormatException
```
    This method returns the int value in the table at a specified row/column location.
    
    Parameters:
    
    row - primary key of row
    
    column - index of column to retrieve (starting at zero)
    
    Returns:
    
    the value in that position as an int
    
    Throws:
    
    NumberFormatException - if the cell does not contain an int value.
  - getDoubleCell
```
double getDoubleCell(int row,
                     String column)
              throws NumberFormatException
```
    This method returns the double value in the table at a specified row/column location.
    
    Parameters:
    
    row - index of row to retrieve (starting at zero)
    
    column - the name of the desired column
    
    Returns:
    
    the value in that position as an int
    
    Throws:
    
    NumberFormatException - if the cell does not contain a double value.
  - getDoubleCell
```
double getDoubleCell(int row,
                     int column)
              throws NumberFormatException
```
    This method returns the double value in the table at a specified row/column location.
    
    Parameters:
    
    row - index of row to retrieve (starting at zero)
    
    column - index of column to retrieve (starting at zero)
    
    Returns:
    
    the value in that position as an int
    
    Throws:
    
    NumberFormatException - if the cell does not contain a double value.
  - getDoubleCell
```
double getDoubleCell(String row,
                     String column)
              throws NumberFormatException
```
    This method returns the double value in the table at a specified row/column location.
    
    Parameters:
    
    row - primary key of row
    
    column - the name of the desired column
    
    Returns:
    
    the value in that position as an int
    
    Throws:
    
    NumberFormatException - if the cell does not contain a double value.
  - getDoubleCell
```
double getDoubleCell(String row,
                     int column)
              throws NumberFormatException
```
    This method returns the double value in the table at a specified row/column location.
    
    Parameters:
    
    row - primary key of row
    
    column - index of column to retrieve (starting at zero)
    
    Returns:
    
    the value in that position as an int
    
    Throws:
    
    NumberFormatException - if the cell does not contain a double value.
  - getRow
```
DataTable.Row getRow(int row)
```
    This method returns a map that represents the desired row (indicated by the primary key).
    
    Parameters:
    
    row - index of row to retrieve (starting from zero)
    
    Returns:
    
    the Map representing the desired row.
  - getRow
```
DataTable.Row getRow(String row)
```
    This method returns a Map that represents the desired row. The map is a map of column names to values.
    
    Parameters:
    
    row - primary key of row to retrieve
    
    Returns:
    
    the Map representing the desired row.
  - setCell
```
void setCell(int row,
             String column,
             String value)
```
    This method allows you to update a desired row and column with new data as a String.
    
    Parameters:
    
    row - index of row to change (starting from zero)
    
    column - name of the column to change
    
    value - the value that is to replace the current value
  - setCell
```
void setCell(int row,
             String column,
             int value)
```
    This method allows you to update a desired row and column with new data as an int.
    
    Parameters:
    
    row - index of row to change (starting from zero)
    
    column - name of the column to change
    
    value - the value that is to replace the current value
  - setCell
```
void setCell(int row,
             String column,
             double value)
```
    This method allows you to update a desired row and column with new data as a double.
    
    Parameters:
    
    row - index of row to change (starting from zero)
    
    column - name of the column to change
    
    value - the value that is to replace the current value
  - setCell
```
void setCell(int row,
             int column,
             String value)
```
    This method allows you to update a desired row and column with new data as a String.
    
    Parameters:
    
    row - index of row to change (starting from zero)
    
    column - index of column to change (starting from zero)
    
    value - the value that is to replace the current value
  - setCell
```
void setCell(int row,
             int column,
             int value)
```
    This method allows you to update a desired row and column with new data as an int.
    
    Parameters:
    
    row - index of row to change (starting from zero)
    
    column - index of column to change (starting from zero)
    
    value - the value that is to replace the current value
  - setCell
```
void setCell(int row,
             int column,
             double value)
```
    This method allows you to update a desired row and column with new data as a double.
    
    Parameters:
    
    row - index of row to change (starting from zero)
    
    column - index of column to change (starting from zero)
    
    value - the value that is to replace the current value
  - setCell
```
void setCell(String row,
             String column,
             String value)
```
    This method allows you to update a desired row and column with new data as a String.
    
    Parameters:
    
    row - primary key of the row to change
    
    column - name of the column to change
    
    value - the value that is to replace the current value
  - setCell
```
void setCell(String row,
             String column,
             int value)
```
    This method allows you to update a desired row and column with new data as an int.
    
    Parameters:
    
    row - primary key of the row to change
    
    column - name of the column to change
    
    value - the value that is to replace the current value
  - setCell
```
void setCell(String row,
             String column,
             double value)
```
    This method allows you to update a desired row and column with new data as a double.
    
    Parameters:
    
    row - primary key of the row to change
    
    column - name of the column to change
    
    value - the value that is to replace the current value
  - setCell
```
void setCell(String row,
             int column,
             String value)
```
    This method allows you to update a desired row and column with new data as a String.
    
    Parameters:
    
    row - primary key of the row to change
    
    column - index of column to change (starting from zero)
    
    value - the value that is to replace the current value
  - setCell
```
void setCell(String row,
             int column,
             int value)
```
    This method allows you to update a desired row and column with new data as an int.
    
    Parameters:
    
    row - primary key of the row to change
    
    column - index of column to change (starting from zero)
    
    value - the value that is to replace the current value
  - setCell
```
void setCell(String row,
             int column,
             double value)
```
    This method allows you to update a desired row and column with new data as a double.
    
    Parameters:
    
    row - primary key of the row to change
    
    column - index of column to change (starting from zero)
    
    value - the value that is to replace the current value
  - removeRow
```
DataTable.Row removeRow(int row)
```
    This method removes the row identified by row number. The method permanently deletes the row from the table and when the table is queried the row will not be accessible either. As with in others, this is independent of the primary key and just the arbitrary ordering of the table. The method also renumbers the rows so that if the primary key remains the default, then the row numbers will be consistent between using the integer-based row numbers and their String equivalents.
    
    Parameters:
    
    row - table row to be deleted.
    
    Returns:
    
    the Map representing the Row that was removed from the table.
  - removeRow
```
DataTable.Row removeRow(String row)
```
    This method removes the row (to be determined by the key). The method permanently deletes the row from the table and when the table is queried the row will not be accessible either. The method also renumbers the rows so that if the primary key remains the default, then the row numbers will be consistent between using the integer-based row numbers and their String equivalents.
    
    Parameters:
    
    row - table row to be deleted.
    
    Returns:
    
    the Map representing the Row that was removed from the table.
  - addColumn
```
void addColumn(String columnName)
```
    This method adds a column to the table. For each row in the table, the column's value will be null.
    
    Parameters:
    
    columnName - the name of the column to be added.
  - addColumn
```
void addColumn(String columnName,
               String defaultValue)
```
    This method adds a column to the table, setting this column to the specified default value in every row.
    
    Parameters:
    
    columnName - the name of the column to be added.
    
    defaultValue - the default value to use for the column.
  - addRow
```
void addRow(DataTable.Row row)
```
    This method adds a row to the table. For each column, the Map should have a value for the column name. If not, that column value is null. The method also renumbers the rows so that if the primary key remains the default, then the row numbers will be consistent between using the integer-based row numbers and their String equivalents.
    
    Parameters:
    
    row - The row to add
  - setPrimaryKey
```
void setPrimaryKey(String key)
```
    This method sets the column name that acts as the primary key for the table. If the column name is not in the table, then the primary key stays as the current primary key. The method also renumbers the rows so that if the primary key remains the default, then the row numbers will be consistent between using the integer-based row numbers and their String equivalents.
    
    Parameters:
    
    key - the column name to be set as the primary key.
  - getPrimaryKey
```
String getPrimaryKey()
```
    This method returns the column name that acts as the primary key for the table.
    
    Returns:
    
    the column name that acts as the primary key. The default is the row number.
  - getColumnNames
```
List<String> getColumnNames()
```
    This method returns a list of the names of all of the columns of the data table. The column names are returned as an array list with each position representing one of the columns in the table.
    
    Returns:
    
    an array list with a reporting of all of the column names in the table.
  - setColumnNames
```
void setColumnNames(List<String> columnNames)
```
    This method sets an arbitrary name for each of the columns in the table.
    
    Parameters:
    
    columnNames - names of columns to be set in the table.
  - setColumnNames
```
void setColumnNames(String... columnNames)
```
    This method sets an arbitrary name for each of the columns in the table.
    
    Parameters:
    
    columnNames - names of columns to be set in the table.
  - remapColumnNames
```
void remapColumnNames(Map<String,String> columnMap)
```
    This method replaces each column name in the table with a matching key in columnMap with the value of the mapping.
    
    Parameters:
    
    columnMap - names of columns to be replaced with the associated value to replace it with.
  - getAllRows
```
List<DataTable.Row> getAllRows()
```
    This method returns a representation of the Data Table. The representation is an array list where each position represents a row. Each row is a map with an unordered collection of columns.
    
    Returns:
    
    an array list representing the data table.
  - copyRowsFrom
```
void copyRowsFrom(DataTable dataSet)
```
    This method copies an existing DataTable's rows into the DataTable. The primary key remains what it was before the copy and the incoming DataTable completely replaces the current DataTable.
    
    Parameters:
    
    dataSet - a DataTable object to copy into the current DataTable.
  - count
```
int count(String column,
          String value)
```
    This method counts the number of rows in the specified column that have the value given by the value parameter.
    
    Parameters:
    
    column - the desired column to count on.
    
    value - the desired value to count.
    
    Returns:
    
    the count of the number of rows that have the value given by the value parameter.
  - avg
```
double avg(String column)
    throws NumberFormatException
```
    This method computes the average of a column that has numeric values. Throws an exception if a non-number is found in the column.
    
    Parameters:
    
    column - the column to compute the average of.
    
    Returns:
    
    the average of the numerical values in the column.
    
    Throws:
    
    NumberFormatException - if the column has a string that cannot be parsed as a number.
  - max
```
double max(String column)
    throws NumberFormatException
```
    This method computes the maximum value of a column that has numeric values. Throws an exception if a non-number is found in the column.
    
    Parameters:
    
    column - the column to compute the max number of.
    
    Returns:
    
    the max of the numerical values in the column.
    
    Throws:
    
    NumberFormatException - if the column has a string that cannot be parsed as a number.
  - min
```
double min(String column)
    throws NumberFormatException
```
    This method computes the minimum value of a column that has numeric values. Throws an exception if a non-number is found in the column.
    
    Parameters:
    
    column - the column to compute the min number of.
    
    Returns:
    
    the min of the numerical values in the column.
    
    Throws:
    
    NumberFormatException - if the column has a string that cannot be parsed as a number.
  - save
```
void save(String filename)
```
    This method saves the data table that has been generated/manipulated in the format desired for the implementation of the interface.
    
    Parameters:
    
    filename - the path to the file that is to be written.

Interface DataTable

Nested Class Summary

Method Summary

Methods inherited from interface java.lang.Iterable

Method Detail

rowCount

colCount

getCell

getCell

getCell

getCell

getIntCell

getIntCell

getIntCell

getIntCell

getDoubleCell

getDoubleCell

getDoubleCell

getDoubleCell

getRow

getRow

setCell

setCell

setCell

setCell

setCell

setCell

setCell

setCell

setCell

setCell

setCell

setCell

removeRow

removeRow

addColumn

addColumn

addRow

setPrimaryKey

getPrimaryKey

getColumnNames

setColumnNames

setColumnNames

remapColumnNames

getAllRows

copyRowsFrom

count

avg

max

min

save