bradleyross.library.helpers

Class ServletHelpers

java.lang.Object

bradleyross.library.helpers.ServletHelpers

public class ServletHelpers
extends Object

General purpose helpers for use in creating servlets.

Author:

- Bradley Ross

Field Summary

Fields

Modifier and Type	Field and Description
protected DatabaseProperties	data

Constructor Summary

Constructors

Constructor and Description
ServletHelpers(DatabaseProperties dataValue)

Method Summary

Methods

Modifier and Type	Method and Description
static Date	buildDate(int year, int month, int day) Construct an SQL date using the year, month, and day
static Date	buildDate(String yearValue, String monthValue, String dayValue) Construct an SQL date using the year, month, and day
static String	doubleDoubleQuotes(String value) Replace occurrences of double quotes with two double quote characters.
static String	escapeDoubleQuotes(String value) Replace occurrences of double quotes with a back slash followed by a double quote.
static String	formatElapsedTime(long startTime) This method is intended to help in showing the elapsed time for generating a page.
static float	getFloatValue(ResultSet rs, String columnName) Return a floating point value from a result set, returning zero if the value in the result set was null.
static float	getFloatValue(ResultSet rs, String columnName, float defaultValue) Return a floating point value from the result set.
static String	getStringValue(ResultSet rs, String columnName) Return the contents of a character column in a result set as a String object.
static String	getStringValue(ResultSet rs, String columnName, String defaultValue) Return a character value from a result set as a String object.
static String	getStringValueEscaped(ResultSet rs, String columnName) Return the contents of a character column in a result set as a String object.
static String	getStringValueEscaped(ResultSet rs, String columnName, String defaultValue) Return a character value from a result set as a String object.
static void	main(String[] args) Test driver.
static void	setChar(PreparedStatement stmt, int position, ResultSet rs, String name) Set a CHAR column in a prepared statement.
static void	setChar(PreparedStatement stmt, int position, ResultSet rs, String name, boolean toUpperCase) Set a CHAR column in a prepared statement.
static void	setChar(PreparedStatement stmt, int position, String value) Set a CHAR column in a prepared statement.
static void	setChar(PreparedStatement stmt, int position, String value, boolean toUpperCase) Set a CHAR column in a prepared statement.
static void	setFloat(PreparedStatement stmt, int position, Float value) Set a FLOAT column in a prepared statement.
static void	setFloat(PreparedStatement stmt, int position, ResultSet rs, String name) Set a FLOAT column in a prepared statement.
static void	setInteger(PreparedStatement stmt, int position, Integer value) Set a INTEGER column in a prepared statement.
static void	setInteger(PreparedStatement stmt, int position, ResultSet rs, Integer name) Set a INTEGER column in a prepared statement.
static void	setVarchar(PreparedStatement stmt, int position, ResultSet rs, String name) Set a VARCHAR column in a prepared statement.
static void	setVarchar(PreparedStatement stmt, int position, ResultSet rs, String name, boolean toUpperCase) Set a VARCHAR column in a prepared statement.
static void	setVarchar(PreparedStatement stmt, int position, String value) Set a VARCHAR column in a prepared statement.
static void	setVarchar(PreparedStatement stmt, int position, String value, boolean toUpperCase) Set a VARCHAR column in a prepared statement.
static String	showParameters(HttpServletRequest request) Place information on the parameters in the body of the servlet.
static String	valueWithDefault(String value, String ifDefault) Returns a default value if the examined value is null.

Methods inherited from class java.lang.Object

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

Field Detail

data

protected DatabaseProperties data

Constructor Detail

ServletHelpers

public ServletHelpers(DatabaseProperties dataValue)

Method Detail

formatElapsedTime

public static String formatElapsedTime(long startTime)

This method is intended to help in showing the elapsed time for generating a page.

By using this method, you avoid the possibility of the value for milliseconds displaying with over a dozen digits due to round-off error.

Parameters:

startTime - Date (in milliseconds that was generated using a previous java.util.Date object.

Returns:

Formatted string containing the elapsed time in milliseconds

See Also:

Date, NumberFormat

valueWithDefault

public static String valueWithDefault(String value,
                      String ifDefault)

Returns a default value if the examined value is null.

Trying to run a number of String methods, such as equals or equalsIgnoreCase, result in exeptions being thrown if the object being examined has a value of null

Parameters:

value - String value to be examined

ifDefault - Default value to be used if value is null

Returns:

String containing either examined or default value

doubleDoubleQuotes

public static String doubleDoubleQuotes(String value)

Replace occurrences of double quotes with two double quote characters.

Parameters:

value - String to be processed

Returns:

Processed string

escapeDoubleQuotes

public static String escapeDoubleQuotes(String value)

Replace occurrences of double quotes with a back slash followed by a double quote.

Parameters:

value - String to be processed

Returns:

Processed string

getStringValue

public static String getStringValue(ResultSet rs,
                    String columnName,
                    String defaultValue)
                             throws SQLException

Return a character value from a result set as a String object.

Parameters:

rs - Result set to be used

columnName - Name of column to be read

defaultValue - Default value if column in result set has a value of null

Returns:

Character data

Throws:

SQLException

getStringValueEscaped

public static String getStringValueEscaped(ResultSet rs,
                           String columnName,
                           String defaultValue)
                                    throws SQLException

Return a character value from a result set as a String object.

Parameters:

rs - Result set to be read

columnName - Name of column to be read

defaultValue - Default value to be used in value in database is null

Returns:

Character data

Throws:

SQLException

getStringValue

public static String getStringValue(ResultSet rs,
                    String columnName)
                             throws SQLException

Return the contents of a character column in a result set as a String object.

Parameters:

rs - Result set to be read

columnName - Name of column to be read

Returns:

Character data from database

Throws:

SQLException

getStringValueEscaped

public static String getStringValueEscaped(ResultSet rs,
                           String columnName)
                                    throws SQLException

Return the contents of a character column in a result set as a String object.

This method escapes the character strings using the HTML character entity literals before returning the data to the calling program.

Parameters:

rs - Result set to be read

columnName - Name of column to be read

Returns:

Character data from database

Throws:

SQLException

getFloatValue

public static float getFloatValue(ResultSet rs,
                  String columnName,
                  float defaultValue)
                           throws SQLException

Return a floating point value from the result set.

Parameters:

rs - ResultSet object containing information

columnName - Name of column in result set

defaultValue - Value to be returned if value of column is null

Returns:

Value from result set

Throws:

SQLException

getFloatValue

public static float getFloatValue(ResultSet rs,
                  String columnName)
                           throws SQLException

Return a floating point value from a result set, returning zero if the value in the result set was null.

Parameters:

rs - Result set from which data is to be taken

columnName - Name of column in result set

Returns:

Floating point value from result set

Throws:

SQLException

setChar

public static void setChar(PreparedStatement stmt,
           int position,
           String value)
                    throws SQLException

Set a CHAR column in a prepared statement.

Parameters:

stmt - Prepared statement

position - Position in prepared statement

value - Value to be used for parameter

Throws:

SQLException

setChar

public static void setChar(PreparedStatement stmt,
           int position,
           String value,
           boolean toUpperCase)
                    throws SQLException

Set a CHAR column in a prepared statement.

Parameters:

stmt - Prepared statement

position - Position in prepared statement

value - Value to be used for parameter

toUpperCase - True means strings are converted to upper case

Throws:

SQLException

setChar

public static void setChar(PreparedStatement stmt,
           int position,
           ResultSet rs,
           String name)
                    throws SQLException

Set a CHAR column in a prepared statement.

Parameters:

stmt - Prepared statement

position - Position in prepared statement

rs - Result set containing value to be used for parameter

name - Name of column in result set

Throws:

SQLException

setChar

public static void setChar(PreparedStatement stmt,
           int position,
           ResultSet rs,
           String name,
           boolean toUpperCase)
                    throws SQLException

Set a CHAR column in a prepared statement.

Parameters:

stmt - Prepared statement

position - Position in prepared statement

rs - Result set containing value to be used for parameter

name - Name of column in result set

toUpperCase - True means strings are converted to upper case

Throws:

SQLException

setVarchar

public static void setVarchar(PreparedStatement stmt,
              int position,
              String value)
                       throws SQLException

Set a VARCHAR column in a prepared statement.

Parameters:

stmt - Prepared statement

position - Position in prepared statement

value - Value to be used for parameter

Throws:

SQLException

setVarchar

public static void setVarchar(PreparedStatement stmt,
              int position,
              String value,
              boolean toUpperCase)
                       throws SQLException

Set a VARCHAR column in a prepared statement.

Parameters:

stmt - Prepared statement

position - Position in prepared statement

value - Value to be used for parameter

toUpperCase - True means that strings are converted to upper case

Throws:

SQLException

setVarchar

public static void setVarchar(PreparedStatement stmt,
              int position,
              ResultSet rs,
              String name)
                       throws SQLException

Set a VARCHAR column in a prepared statement.

Parameters:

stmt - Prepared statement

position - Position in prepared statement

rs - Result set containing value to be used for parameter

name - Name of column in result set

Throws:

SQLException

setVarchar

public static void setVarchar(PreparedStatement stmt,
              int position,
              ResultSet rs,
              String name,
              boolean toUpperCase)
                       throws SQLException

Set a VARCHAR column in a prepared statement.

Parameters:

stmt - Prepared statement

position - Position in prepared statement

rs - Result set containing value to be used for parameter

name - Name of column in result set

toUpperCase - True means that strings are to be converted to upper case

Throws:

SQLException

setFloat

public static void setFloat(PreparedStatement stmt,
            int position,
            Float value)
                     throws SQLException

Set a FLOAT column in a prepared statement.

Parameters:

stmt - Prepared statement

position - Position in prepared statement

value - Value to be used for parameter

Throws:

SQLException

setFloat

public static void setFloat(PreparedStatement stmt,
            int position,
            ResultSet rs,
            String name)
                     throws SQLException

Set a FLOAT column in a prepared statement.

Parameters:

stmt - Prepared statement

position - Position in prepared statement

rs - Result set containing value to be used for parameter

name - Name of column in result set

Throws:

SQLException

setInteger

public static void setInteger(PreparedStatement stmt,
              int position,
              Integer value)
                       throws SQLException

Set a INTEGER column in a prepared statement.

Parameters:

stmt - Prepared statement

position - Position in prepared statement

value - Value to be used for parameter

Throws:

SQLException

setInteger

public static void setInteger(PreparedStatement stmt,
              int position,
              ResultSet rs,
              Integer name)
                       throws SQLException

Set a INTEGER column in a prepared statement.

Parameters:

stmt - Prepared statement

position - Position in prepared statement

rs - Result set containing value to be used for parameter

name - Name of column in result set

Throws:

SQLException

buildDate

public static Date buildDate(String yearValue,
             String monthValue,
             String dayValue)

Construct an SQL date using the year, month, and day

Parameters:

yearValue - Year (4 digit)

monthValue - Number of Month (January = 1)

dayValue - Day of month

Returns:

SQL date

buildDate

public static Date buildDate(int year,
             int month,
             int day)

Construct an SQL date using the year, month, and day

Parameters:

year - Year (4 digit)

month - Number of month (January = 1)

day - Day of month

Returns:

SQL date

showParameters

public static String showParameters(HttpServletRequest request)

Place information on the parameters in the body of the servlet.

This is intended for debugging purposes.

Parameters:

request - Request object

Returns:

Text to be included in HTML document

main

public static void main(String[] args)

Test driver.

Parameters:

args - Not used in this program