// Adding a clone method to PhoneNumber - page 55
package org.effectivejava.examples.chapter03.item11;
import java.util.HashMap;
import java.util.Map;
public final class PhoneNumber implements Cloneable {
private final short areaCode;
private final short prefix;
private final short lineNumber;
public PhoneNumber(int areaCode, int prefix, int lineNumber) {
rangeCheck(areaCode, 999, "area code");
rangeCheck(prefix, 999, "prefix");
rangeCheck(lineNumber, 9999, "line number");
this.areaCode = (short) areaCode;
this.prefix = (short) prefix;
this.lineNumber = (short) lineNumber;
}
private static void rangeCheck(int arg, int max, String name) {
if (arg < 0 || arg > max)
throw new IllegalArgumentException(name + ": " + arg);
}
@Override
public boolean equals(Object o) {
if (o == this)
return true;
if (!(o instanceof PhoneNumber))
return false;
PhoneNumber pn = (PhoneNumber) o;
return pn.lineNumber == lineNumber && pn.prefix == prefix
&& pn.areaCode == areaCode;
}
@Override
public int hashCode() {
int result = 17;
result = 31 * result + areaCode;
result = 31 * result + prefix;
result = 31 * result + lineNumber;
return result;
}
/**
* Returns the string representation of this phone number. The string
* consists of fourteen characters whose format is "(XXX) YYY-ZZZZ", where
* XXX is the area code, YYY is the prefix, and ZZZZ is the line number.
* (Each of the capital letters represents a single decimal digit.)
*
* If any of the three parts of this phone number is too small to fill up
* its field, the field is padded with leading zeros. For example, if the
* value of the line number is 123, the last four characters of the string
* representation will be "0123".
*
* Note that there is a single space separating the closing parenthesis
* after the area code from the first digit of the prefix.
*/
@Override
public String toString() {
return String.format("(%03d) %03d-%04d", areaCode, prefix, lineNumber);
}
@Override
public PhoneNumber clone() {
try {
return (PhoneNumber) super.clone();
} catch (CloneNotSupportedException e) {
throw new AssertionError(); // Can't happen
}
}
public static void main(String[] args) {
PhoneNumber pn = new PhoneNumber(707, 867, 5309);
Map<PhoneNumber, String> m = new HashMap<PhoneNumber, String>();
m.put(pn, "Jenny");
System.out.println(m.get(pn.clone()));
}
}