hirondelle.stocks.portfolio
Class RegexInputVerifier

Object
  InputVerifier
      RegexInputVerifier

final class RegexInputVerifier
extends InputVerifier

Verifies user input into a JTextComponent versus a regular expression.

This class is likely useful for a wide number of simple input needs. See the Pattern class for details regarding regular expressions.

The main(java.lang.String...) method is provided as a developer tool for testing regular expressions versus user input, but the principal use of this class is to be passed to JComponent.setInputVerifier(javax.swing.InputVerifier).

Upon detection of invalid input, this class takes the following actions :

• emit a beep
• overwrite the JTextComponent to display the following: INVALID: " (input data) "
• optionally, append the tooltip text to the content of the INVALID message ; this is useful only if the tooltip contains helpful information regarding input. Warning : appending the tooltip text may cause the error text to be too long for the corresponding text field.

The user of this class is encouraged to always place conditions on data entry in the tooltip for the corresponding field.

Nested Class Summary

(package private) static class

RegexInputVerifier.UseToolTip Enumeration compels the caller to use a style which reads clearly.

Field Summary

(package private) static String	ERROR_MESSAGE_START The text which begins all error messages.
(package private) static RegexInputVerifier	FLOATING_POINT Convenience object for input of decimals numbers, eg -23.23321, 100.25.
(package private) static RegexInputVerifier	INTEGER Convenience object for input of integers: ...-2,-1,0,1,2...
(package private) static RegexInputVerifier	MONEY Convenience object for input of money values, eg -23, 100.25.
(package private) static RegexInputVerifier	NON_NEGATIVE_FLOATING_POINT Convenience object for input of non-negative decimals numbers, eg 23.23321, 100.25.
(package private) static RegexInputVerifier	NON_NEGATIVE_INTEGER Convenience object for input of these integers: 0,1,2...
(package private) static RegexInputVerifier	NON_NEGATIVE_MONEY Convenience object for input of non-negative money values, eg 23, 100.25.
(package private) static RegexInputVerifier	TEXT Convenience object for input of short amounts of text.

Constructor Summary

RegexInputVerifier(Pattern aPattern, RegexInputVerifier.UseToolTip aUseToolTip)
Constructor.

Method Summary

static void	main(String... aArgs) Developer test harness for verifying a regular expression, using a simple graphical interface and a RegexInputVerifier.
boolean	shouldYieldFocus(JComponent aComponent) Always returns true, in this implementation, such that focus can always transfer to another component whenever the validation fails.
boolean	verify(JComponent aComponent) Return true only if the untrimmed user input matches the regular expression provided to the constructor.

Methods inherited from class Object

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

Field Detail

ERROR_MESSAGE_START

static final String ERROR_MESSAGE_START

The text which begins all error messages. The caller may examine their text fields for the presence of ERROR_MESSAGE_START, before processing input.

See Also:

Constant Field Values

INTEGER

static final RegexInputVerifier INTEGER

Convenience object for input of integers: ...-2,-1,0,1,2...

From 1 to 9 digits, possibly preceded by a minus sign. Corresponds approximately to the spec of Integer.parseInt. The limit on the number of digits is related to size of Integer.MAX_VALUE and Integer.MIN_VALUE.

NON_NEGATIVE_INTEGER

static final RegexInputVerifier NON_NEGATIVE_INTEGER

Convenience object for input of these integers: 0,1,2...

As in INTEGER, but with no leading minus sign.

TEXT

static final RegexInputVerifier TEXT

Convenience object for input of short amounts of text.

Text contains from 1 to 75 non-whitespace characters.

FLOATING_POINT

static final RegexInputVerifier FLOATING_POINT

Convenience object for input of decimals numbers, eg -23.23321, 100.25.

Possible leading minus sign, 1 to 10 digits before the decimal, and 1 to 10 digits after the decimal.

NON_NEGATIVE_FLOATING_POINT

static final RegexInputVerifier NON_NEGATIVE_FLOATING_POINT

Convenience object for input of non-negative decimals numbers, eg 23.23321, 100.25.

As in FLOATING_POINT, but no leading minus sign.

MONEY

static final RegexInputVerifier MONEY

Convenience object for input of money values, eg -23, 100.25.

Possible leading minus sign, from 1 to 15 leading digits, and optionally a decimal place and two decimals.

NON_NEGATIVE_MONEY

static final RegexInputVerifier NON_NEGATIVE_MONEY

Convenience object for input of non-negative money values, eg 23, 100.25.

As in MONEY, except no leading minus sign

Constructor Detail

RegexInputVerifier

RegexInputVerifier(Pattern aPattern,
                   RegexInputVerifier.UseToolTip aUseToolTip)

Constructor.

Parameters:

aPattern - regular expression against which all user input will be verified; aPattern.pattern satisfies Util.textHasContent(java.lang.String).

aUseToolTip - indicates if the tooltip text should be appended to error messages displayed to the user.

Method Detail

shouldYieldFocus

public boolean shouldYieldFocus(JComponent aComponent)

Always returns true, in this implementation, such that focus can always transfer to another component whenever the validation fails.

If super.shouldYieldFocus returns false, then notify the user of an error.

Overrides:

shouldYieldFocus in class InputVerifier

Parameters:

aComponent - is a JTextComponent.

verify

public boolean verify(JComponent aComponent)

Return true only if the untrimmed user input matches the regular expression provided to the constructor.

Specified by:

verify in class InputVerifier

Parameters:

aComponent - must be a JTextComponent.

main

public static void main(String... aArgs)

Developer test harness for verifying a regular expression, using a simple graphical interface and a RegexInputVerifier.

Use of the GUI is straightforward :

• Enter a regular expression (regex).
• Hit the Set Regex button to begin testing input versus the regex.
• Enter text into the Text Input field.
• When focus moves out of the Text Input field, then the input is verified versus the regex.
• To try out another regex, simply enter a new one and hit the Set Regex button.
• Tooltips offer simple reminders as well.

(For running this test harness, RegexInputVerifier needs to be a public class; after testing is finished, it is probably a good idea to change the scope to package-private, since the services of this class are used only by the user interface layer.)