ej.bon

Class Constants

java.lang.Object

ej.bon.Constants

public class Constants
extends Object

This class provides access to compile-time constants. A constant is retrieved from its name, and is replaced by its value using the desired getXXX method depending on the expected type.

The constant name must be resolved by the compiler as a String literal at the location where the getXXX method is called. Constant Expressions are specified in section 15.28 Constant Expressions of the Java Language Specification.

The following usages are allowed:

 // Name is a String Literal
 boolean value = Constants.getBoolean("MyConstant")
 

 // Name is a Field Access to a static final field declaration
 // of type String, and initialized with a Constant Expression
 static final String MY_CONSTANT = "My" + "Constant";
 boolean value = Constants.getBoolean(MY_CONSTANT)
 

The following usages are not allowed:

 // Name is a String Object
 boolean value = Constants.getBoolean(new String("MyConstant"))
 

 // Name is a Field Access to a static final field declaration
 // of type String, but not initialized with a Constant Expression
 static final String MY_CONSTANT = getMyConstantName();
 boolean value = Constants.getBoolean(MY_CONSTANT)
 

Method Summary

Modifier and Type	Method and Description
static boolean	getBoolean(String name) Gets a boolean constant.
static byte	getByte(String name) Gets a byte constant.
static char	getChar(String name) Gets a char constant.
static Class<?>	getClass(String name) Gets a Class constant.
static double	getDouble(String name) Gets a double constant.
static float	getFloat(String name) Gets a float constant.
static int	getInt(String name) Gets an int constant.
static long	getLong(String name) Gets a long constant.
static short	getShort(String name) Gets a short constant.
static String	getString(String name) Gets a String constant.

Methods inherited from class java.lang.Object

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

Method Detail

getBoolean

public static boolean getBoolean(String name)

Gets a boolean constant.

The constant is resolved to true if its value is equals to "true", false if its value is equals to "false".

Parameters:

name - the constant name

Returns:

the boolean constant

getByte

public static byte getByte(String name)

Gets a byte constant.

The constant is resolved to a byte if its value is resolved to an int included into the range [-128,127].

Parameters:

name - the constant name

Returns:

the byte constant

See Also:

getInt(String)

getChar

public static char getChar(String name)

Gets a char constant.

The constant is resolved to a char if its value is resolved to an int included into the range [0,65535].

Parameters:

name - the constant name

Returns:

the char constant

See Also:

getInt(String)

getClass

public static Class<?> getClass(String name)

Gets a Class constant.

The constant is resolved to a Class if its value describes the fully qualified name of a Class that can be loaded from the classpath.

Parameters:

name - the constant name

Returns:

the Class constant

getDouble

public static double getDouble(String name)

Gets a double constant.

The constant is resolved to a double if its value can be loaded by Double.valueOf(String).

Parameters:

name - the constant name

Returns:

the short constant

getFloat

public static float getFloat(String name)

Gets a float constant.

The constant is resolved to a float if its value can be loaded by Float.valueOf(String).

Parameters:

name - the constant name

Returns:

the float constant

getInt

public static int getInt(String name)

Gets an int constant.

The constant is resolved to an int if its String value:

• is a valid argument for Integer.decode(String)
• is an unsigned integer written in hexadecimal format such as 0xFFFFFFFF. In this latter case, the constant is resolved to -1.

Parameters:

name - the constant name

Returns:

the int constant

getLong

public static long getLong(String name)

Gets a long constant.

The constant is resolved to a long if its String value:

• is a valid argument for Long.decode(String)
• if an unsigned long written in hexadecimal format such as 0xFFFFFFFFFFFFFFFF. In this latter case, the constant is resolved to -1.

Parameters:

name - the constant name

Returns:

the long constant

getShort

public static short getShort(String name)

Gets a short constant.

The constant is resolved to a short if its value is resolved to an int included into the range [-32768,32767].

Parameters:

name - the constant name

Returns:

the short constant

See Also:

getInt(String)

getString

public static String getString(String name)

Gets a String constant.

Parameters:

name - the constant name

Returns:

the String constant