13.5 The wrapper classes > 13.5.3 How to get primitive values from the wrapper objects?

13.5.3 How to get primitive values from the wrapper objects?

All wrapper class has a typeValue() method which returns the value of the corresponding primitive type. For example,

Boolean boolObject = new Boolean(true);

if(boolObject.booleanValue())

    System.out.println(“It’s true!”);   // printed

The Boolean wrapper class has a booleanValue() method that return boolean value wrapped by the object. Table 13.5 summarizes the typeValue()method signatures and which wrapper classes define these methods.

Table 13.5 The typeValue() methods and the wrapper classes

The six wrapper classes for numeric types (Byte, Short, Integer, Long, Float and Double) have the typeValue() methods that return a primitive values to any of the six numeric types. Therefore these numeric wrapper classes have six typeValue() methods: - byteValue(), shortValue(), intValue(), longValue, floatValue() and doubleValue(). These six methods make it possible to get any numeric primitive value from a wrapper object of any of the six numeric types.

Integer intObj = new Integer(45); // make a new wrapper object

byte b = intObj.byteValue(); //assigns a byte value 45 to b

short s = intObj.shortValue(); // assigns a short value 45 to s

int i = intObj.intValue(); // assigns a int value 45 to i

long l = intObj.longValue(); // assigns a long value 45L to l

float f = intObj.floatValue(); // assigns a float value 45.0 to f

double d = intObj.doubleValue(); // assigns a double value 45.0 to d

Besides the six typeValue() methods for numeric types, Table 13.5 shows two more methods. The booleanValue() method is defined only in the Boolean wrapper class. Similarly the charValue() method is defined only in the Character wrapper class. Boolean and Character class do not have any other typeValue() method.