Class Histogram

java.lang.Object
  |
  +--Histogram

public class Histogram

extends java.lang.Object

Environment-Based Applications:
The Histogram class constructs a histogram of a set of integer values.

Version:

1 December 2002

Constructor Summary

Histogram(java.lang.String title, int[] values, int maxValue)
Constructs a histogram for the specified values and displays it.

Histogram(java.lang.String title, int numValues, int maxValue)
Constructs a histogram for a certain number of values.

Method Summary

void	display() Displays the histogram.
void	labelColumns() Label the "x-axis" of the histogram with the values represented by each column.
void	labelColumns(int periodicity) Label the "x-axis" of the histogram with the values represented by the columns; which columns are labeled depends on the periodicity.
void	plot(int row, int value) Plots a row in the histogram; assumes that the histogram was created with the first constructor.
void	plot(java.lang.String label, int row, int value) Plots a labeled row in the histogram; assumes that the histogram was created with the first constructor.

Methods inherited from class java.lang.Object

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

Constructor Detail

Histogram

public Histogram(java.lang.String title,
                 int numValues,
                 int maxValue)

Constructs a histogram for a certain number of values. (Precondition: numValues < 20.)

Parameters:

title - title for top of window displaying histogram

numValues - the number of values to plot

maxValue - the maximum value that could be plotted; the histogram is scaled so that a full row represents this value

Histogram

public Histogram(java.lang.String title,
                 int[] values,
                 int maxValue)

Constructs a histogram for the specified values and displays it. (Precondition: values.length < 20 and every value in values is less than or equal to maxValue.)

Parameters:

title - title for top of window displaying histogram

values - the list of values to plot

maxValue - the maximum value that could be plotted; the histogram is scaled so that a full row represents this value

Method Detail

plot

public void plot(int row,
                 int value)

Plots a row in the histogram; assumes that the histogram was created with the first constructor. (Precondition: 0 <= row < numValues and 0 <= value <= maxValue, where numValues and maxValue are the values specified when the histogram was constructed.)

Parameters:

row - the row in which a value is to be plotted (0 represents the first row, 1 represents the second row, and so forth)

value - the value to be plotted

plot

public void plot(java.lang.String label,
                 int row,
                 int value)

Plots a labeled row in the histogram; assumes that the histogram was created with the first constructor. (Precondition: 0 <= row < numValues and 0 <= value <= maxValue, where numValues and maxValue are the values specified when the histogram was constructed. Also, label is a short enough string to be displayed in a single cell in the histogram grid.)

Parameters:

label - the label for the row

row - the row in which a value is to be plotted

value - the value to be plotted

labelColumns

public void labelColumns()

Label the "x-axis" of the histogram with the values represented by each column.

labelColumns

public void labelColumns(int periodicity)

Label the "x-axis" of the histogram with the values represented by the columns; which columns are labeled depends on the periodicity. If the periodicity is 1 then every column is labeled; if the periodicity is 2 then every other column is labeled; it it's 3 then every third column is labeled; etc. The first and last columns, however, are always labeled, regardless of the periodicity.

display

public void display()

Displays the histogram.