Java Reference
In-Depth Information
3.1. An Extended Class
To demonstrate subclassing, we start with a basic attribute class de-
signed to store namevalue pairs. Attribute names are human-readable
strings, such as "color" or "location." Attribute values are determined by
the kind of attribute; for example, a "location" may have a string value
representing a street address, or it may be a set of integer values rep-
resenting latitude and longitude.
public class Attr {
private final String name;
private Object value = null;
public Attr(String name) {
this.name = name;
}
public Attr(String name, Object value) {
this.name = name;
this.value = value;
}
public String getName() {
return name;
}
public Object getValue() {
return value;
}
public Object setValue(Object newValue) {
Object oldVal = value;
value = newValue;
return oldVal;
}
public String toString() {
return name + "='" + value + "'";
