72 lines
2.6 KiB
Java
72 lines
2.6 KiB
Java
package com.iluwatar.tolerantreader;
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import java.io.FileInputStream;
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import java.io.FileOutputStream;
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import java.io.IOException;
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import java.io.ObjectInputStream;
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import java.io.ObjectOutputStream;
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import java.util.HashMap;
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import java.util.Map;
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/**
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*
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* RainbowFishSerializer provides methods for reading and writing {@link RainbowFish} objects to
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* file. Tolerant Reader pattern is implemented here by serializing maps instead of
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* {@link RainbowFish} objects. This way the reader does not break even though new properties are
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* added to the schema.
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*
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*/
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public class RainbowFishSerializer {
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private RainbowFishSerializer() {
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}
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/**
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* Write V1 RainbowFish to file
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*/
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public static void writeV1(RainbowFish rainbowFish, String filename) throws IOException {
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Map<String, String> map = new HashMap<>();
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map.put("name", rainbowFish.getName());
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map.put("age", String.format("%d", rainbowFish.getAge()));
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map.put("lengthMeters", String.format("%d", rainbowFish.getLengthMeters()));
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map.put("weightTons", String.format("%d", rainbowFish.getWeightTons()));
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FileOutputStream fileOut = new FileOutputStream(filename);
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ObjectOutputStream objOut = new ObjectOutputStream(fileOut);
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objOut.writeObject(map);
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objOut.close();
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fileOut.close();
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}
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/**
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* Write V2 RainbowFish to file
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*/
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public static void writeV2(RainbowFishV2 rainbowFish, String filename) throws IOException {
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Map<String, String> map = new HashMap<>();
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map.put("name", rainbowFish.getName());
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map.put("age", String.format("%d", rainbowFish.getAge()));
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map.put("lengthMeters", String.format("%d", rainbowFish.getLengthMeters()));
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map.put("weightTons", String.format("%d", rainbowFish.getWeightTons()));
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map.put("angry", Boolean.toString(rainbowFish.getAngry()));
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map.put("hungry", Boolean.toString(rainbowFish.getHungry()));
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map.put("sleeping", Boolean.toString(rainbowFish.getSleeping()));
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FileOutputStream fileOut = new FileOutputStream(filename);
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ObjectOutputStream objOut = new ObjectOutputStream(fileOut);
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objOut.writeObject(map);
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objOut.close();
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fileOut.close();
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}
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/**
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* Read V1 RainbowFish from file
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*/
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public static RainbowFish readV1(String filename) throws IOException, ClassNotFoundException {
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FileInputStream fileIn = new FileInputStream(filename);
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ObjectInputStream objIn = new ObjectInputStream(fileIn);
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Map<String, String> map = (Map<String, String>) objIn.readObject();
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objIn.close();
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fileIn.close();
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return new RainbowFish(map.get("name"), Integer.parseInt(map.get("age")), Integer.parseInt(map
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.get("lengthMeters")), Integer.parseInt(map.get("weightTons")));
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}
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}
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