org.apache.velocity.tools.view.tools
Class ParameterParser

java.lang.Object
  org.apache.velocity.tools.view.tools.ParameterParser

All Implemented Interfaces:

ViewTool

public class ParameterParser

extends java.lang.Object

implements ViewTool

Utility class for easy parsing of ServletRequest parameters.

 Template example(s):
   $pp.foo                ->  bar
   $pp.getNumber('baz')   ->  12.6
   $pp.getInt('baz')      ->  12
   $pp.getNumbers('foo')  ->  [12.6]

 Toolbox configuration:
 <tool>
   <key>pp</key>
   <scope>request</scope>
   <class>org.apache.velocity.tools.view.tools.ParameterParser</class>
 </tool>
 

When used as a view tool, this should only be used in the request scope. This class is, however, quite useful in your application's controller, filter, or action code as well as in templates.

Version:

$Revision: 1.8.2.1 $ $Date: 2004/05/17 17:09:46 $

Author:

Nathan Bubna

Field Summary

private javax.servlet.ServletRequest

request

Constructor Summary

ParameterParser()
Constructs a new instance

ParameterParser(javax.servlet.ServletRequest request)
Constructs a new instance using the specified request.

Method Summary

boolean	exists(java.lang.String key) Convenience method for checking whether a certain parameter exists.
java.lang.String	get(java.lang.String key) Convenience method for use in Velocity templates.
java.lang.Boolean	getBoolean(java.lang.String key)
boolean	getBoolean(java.lang.String key, boolean alternate)
java.lang.Boolean	getBoolean(java.lang.String key, java.lang.Boolean alternate)
double	getDouble(java.lang.String key, double alternate)
double[]	getDoubles(java.lang.String key)
int	getInt(java.lang.String key, int alternate)
int[]	getInts(java.lang.String key)
java.lang.Number	getNumber(java.lang.String key)
java.lang.Number	getNumber(java.lang.String key, java.lang.Number alternate)
java.lang.Number[]	getNumbers(java.lang.String key)
protected javax.servlet.ServletRequest	getRequest() Returns the current ServletRequest for this instance.
java.lang.String	getString(java.lang.String key)
java.lang.String	getString(java.lang.String key, java.lang.String alternate)
java.lang.String[]	getStrings(java.lang.String key)
void	init(java.lang.Object obj) Initializes this instance.
protected java.lang.Number	parseNumber(java.lang.String value) Converts a parameter value into a Number This is used as the base for all numeric parsing methods.
protected void	setRequest(javax.servlet.ServletRequest request) Sets the current ServletRequest

Methods inherited from class java.lang.Object

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

Field Detail

request

private javax.servlet.ServletRequest request

Constructor Detail

ParameterParser

public ParameterParser()

Constructs a new instance

ParameterParser

public ParameterParser(javax.servlet.ServletRequest request)

Constructs a new instance using the specified request.

Parameters:

request - the ServletRequest to be parsed

Method Detail

init

public void init(java.lang.Object obj)

Initializes this instance.

Specified by:

init in interface ViewTool

Parameters:

obj - the current ViewContext or ServletRequest

Throws:

java.lang.IllegalArgumentException - if the param is not a ViewContext or ServletRequest

setRequest

protected void setRequest(javax.servlet.ServletRequest request)

Sets the current ServletRequest

Parameters:

request - the ServletRequest to be parsed

getRequest

protected javax.servlet.ServletRequest getRequest()

Returns the current ServletRequest for this instance.

Returns:

the current ServletRequest

Throws:

java.lang.UnsupportedOperationException - if the request is null

exists

public boolean exists(java.lang.String key)

Convenience method for checking whether a certain parameter exists.

Parameters:

key - the parameter's key

Returns:

true if a parameter exists for the specified key; otherwise, returns false.

get

public java.lang.String get(java.lang.String key)

Convenience method for use in Velocity templates. This allows for easy "dot" access to parameters. e.g. $params.foo instead of $params.getString('foo')

Parameters:

key - the parameter's key

Returns:

parameter matching the specified key or null if there is no matching parameter

getString

public java.lang.String getString(java.lang.String key)

Parameters:

key - the parameter's key

Returns:

parameter matching the specified key or null if there is no matching parameter

getString

public java.lang.String getString(java.lang.String key,
                                  java.lang.String alternate)

Parameters:

key - the desired parameter's key

alternate - The alternate value

Returns:

parameter matching the specified key or the specified alternate String if there is no matching parameter

getBoolean

public java.lang.Boolean getBoolean(java.lang.String key)

Parameters:

key - the desired parameter's key

Returns:

a Boolean object for the specified key or null if no matching parameter is found

getBoolean

public boolean getBoolean(java.lang.String key,
                          boolean alternate)

Parameters:

key - the desired parameter's key

alternate - The alternate boolean value

Returns:

boolean value for the specified key or the alternate boolean is no value is found

getBoolean

public java.lang.Boolean getBoolean(java.lang.String key,
                                    java.lang.Boolean alternate)

Parameters:

key - the desired parameter's key

alternate - the alternate Boolean

Returns:

a Boolean for the specified key or the specified alternate if no matching parameter is found

getNumber

public java.lang.Number getNumber(java.lang.String key)

Parameters:

key - the desired parameter's key

Returns:

a Number for the specified key or null if no matching parameter is found

getNumber

public java.lang.Number getNumber(java.lang.String key,
                                  java.lang.Number alternate)

Parameters:

key - the desired parameter's key

alternate - The alternate Number

Returns:

a Number for the specified key or the specified alternate if no matching parameter is found

getInt

public int getInt(java.lang.String key,
                  int alternate)

Parameters:

key - the desired parameter's key

alternate - The alternate int value

Returns:

the int value for the specified key or the specified alternate value if no matching parameter is found

getDouble

public double getDouble(java.lang.String key,
                        double alternate)

Parameters:

key - the desired parameter's key

alternate - The alternate double value

Returns:

the double value for the specified key or the specified alternate value if no matching parameter is found

getStrings

public java.lang.String[] getStrings(java.lang.String key)

Parameters:

key - the key for the desired parameter

Returns:

an array of String objects containing all of the values the given request parameter has, or null if the parameter does not exist

getNumbers

public java.lang.Number[] getNumbers(java.lang.String key)

Parameters:

key - the key for the desired parameter

Returns:

an array of Number objects for the specified key or null if the parameter does not exist or the parameter does not contain Numbers.

getInts

public int[] getInts(java.lang.String key)

Parameters:

key - the key for the desired parameter

Returns:

an array of int values for the specified key or null if the parameter does not exist or the parameter does not contain ints.

getDoubles

public double[] getDoubles(java.lang.String key)

Parameters:

key - the key for the desired parameter

Returns:

an array of double values for the specified key or null if the parameter does not exist or the parameter does not contain doubles.

parseNumber

protected java.lang.Number parseNumber(java.lang.String value)
                                throws java.lang.NumberFormatException

Converts a parameter value into a Number This is used as the base for all numeric parsing methods. So, sub-classes can override to allow for customized number parsing. (e.g. to handle fractions, compound numbers, etc.)

Parameters:

value - the string to be parsed

Returns:

the value as a Number

Throws:

java.lang.NumberFormatException