71 lines
1.7 KiB
Java
71 lines
1.7 KiB
Java
//: io/Blips.java
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// ©2015 MindView LLC: see Copyright.txt
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// Simple use of Externalizable & a pitfall.
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import java.io.*;
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import static com.mindviewinc.util.Print.*;
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class Blip1 implements Externalizable {
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public Blip1() {
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print("Blip1 Constructor");
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}
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@Override
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public void writeExternal(ObjectOutput out)
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throws IOException {
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print("Blip1.writeExternal");
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}
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@Override
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public void readExternal(ObjectInput in)
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throws IOException, ClassNotFoundException {
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print("Blip1.readExternal");
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}
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}
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class Blip2 implements Externalizable {
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Blip2() {
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print("Blip2 Constructor");
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}
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@Override
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public void writeExternal(ObjectOutput out)
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throws IOException {
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print("Blip2.writeExternal");
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}
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@Override
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public void readExternal(ObjectInput in)
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throws IOException, ClassNotFoundException {
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print("Blip2.readExternal");
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}
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}
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public class Blips {
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public static void main(String[] args)
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throws IOException, ClassNotFoundException {
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print("Constructing objects:");
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Blip1 b1 = new Blip1();
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Blip2 b2 = new Blip2();
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try(ObjectOutputStream o = new ObjectOutputStream(
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new FileOutputStream("Blips.out"))) {
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print("Saving objects:");
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o.writeObject(b1);
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o.writeObject(b2);
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}
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// Now get them back:
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ObjectInputStream in = new ObjectInputStream(
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new FileInputStream("Blips.out"));
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print("Recovering b1:");
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b1 = (Blip1)in.readObject();
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// OOPS! Throws an exception:
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//! print("Recovering b2:");
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//! b2 = (Blip2)in.readObject();
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}
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} /* Output:
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Constructing objects:
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Blip1 Constructor
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Blip2 Constructor
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Saving objects:
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Blip1.writeExternal
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Blip2.writeExternal
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Recovering b1:
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Blip1 Constructor
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Blip1.readExternal
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*///:~
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