Mega Code Archive
Cloning a composed object
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// : appendixa:DeepCopy.java
// Cloning a composed object.
// {Depends: junit.jar}
// From 'Thinking in Java, 3rd ed.' (c) Bruce Eckel 2002
// www.BruceEckel.com. See copyright notice in CopyRight.txt.
import junit.framework.*;
class DepthReading implements Cloneable {
private double depth;
public DepthReading(double depth) {
this.depth = depth;
}
public Object clone() {
Object o = null;
try {
o = super.clone();
} catch (CloneNotSupportedException e) {
e.printStackTrace();
}
return o;
}
public double getDepth() {
return depth;
}
public void setDepth(double depth) {
this.depth = depth;
}
public String toString() {
return String.valueOf(depth);
}
}
class TemperatureReading implements Cloneable {
private long time;
private double temperature;
public TemperatureReading(double temperature) {
time = System.currentTimeMillis();
this.temperature = temperature;
}
public Object clone() {
Object o = null;
try {
o = super.clone();
} catch (CloneNotSupportedException e) {
e.printStackTrace();
}
return o;
}
public double getTemperature() {
return temperature;
}
public void setTemperature(double temperature) {
this.temperature = temperature;
}
public String toString() {
return String.valueOf(temperature);
}
}
class OceanReading implements Cloneable {
private DepthReading depth;
private TemperatureReading temperature;
public OceanReading(double tdata, double ddata) {
temperature = new TemperatureReading(tdata);
depth = new DepthReading(ddata);
}
public Object clone() {
OceanReading o = null;
try {
o = (OceanReading) super.clone();
} catch (CloneNotSupportedException e) {
e.printStackTrace();
}
// Must clone references:
o.depth = (DepthReading) o.depth.clone();
o.temperature = (TemperatureReading) o.temperature.clone();
return o; // Upcasts back to Object
}
public TemperatureReading getTemperatureReading() {
return temperature;
}
public void setTemperatureReading(TemperatureReading tr) {
temperature = tr;
}
public DepthReading getDepthReading() {
return depth;
}
public void setDepthReading(DepthReading dr) {
this.depth = dr;
}
public String toString() {
return "temperature: " + temperature + ", depth: " + depth;
}
}
public class DeepCopy extends TestCase {
public DeepCopy(String name) {
super(name);
}
public void testClone() {
OceanReading reading = new OceanReading(33.9, 100.5);
// Now clone it:
OceanReading clone = (OceanReading) reading.clone();
TemperatureReading tr = clone.getTemperatureReading();
tr.setTemperature(tr.getTemperature() + 1);
clone.setTemperatureReading(tr);
DepthReading dr = clone.getDepthReading();
dr.setDepth(dr.getDepth() + 1);
clone.setDepthReading(dr);
assertEquals(reading.toString(), "temperature: 33.9, depth: 100.5");
assertEquals(clone.toString(), "temperature: 34.9, depth: 101.5");
}
public static void main(String[] args) {
junit.textui.TestRunner.run(DeepCopy.class);
}
} ///:~
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