1 files changed, 118 insertions, 0 deletions
diff --git a/src/main/java/design/persistence/JSONPersonalDatabase.java b/src/main/java/design/persistence/JSONPersonalDatabase.java
new file mode 100644
index 0000000..0efa362
--- /dev/null
+++ b/src/main/java/design/persistence/JSONPersonalDatabase.java
@@ -0,0 +1,118 @@
+package design.persistence;
+
+import com.fasterxml.jackson.annotation.JsonAutoDetect;
+import com.fasterxml.jackson.annotation.JsonCreator;
+import com.fasterxml.jackson.annotation.PropertyAccessor;
+import com.fasterxml.jackson.core.JsonGenerator;
+import com.fasterxml.jackson.core.JsonParser;
+import com.fasterxml.jackson.core.util.DefaultIndenter;
+import com.fasterxml.jackson.core.util.DefaultPrettyPrinter;
+import com.fasterxml.jackson.databind.*;
+import com.fasterxml.jackson.databind.module.SimpleModule;
+import com.fasterxml.jackson.datatype.jsr310.JavaTimeModule;
+import com.fasterxml.jackson.module.paramnames.ParameterNamesModule;
+import design.model.Course;
+import design.model.Golfer;
+
+import java.io.File;
+import java.io.IOException;
+import java.util.HashMap;
+import java.util.Map;
+
+public class JSONPersonalDatabase implements PersonalDatabase {
+
+    private final Map<String, Golfer> cache;
+    private final ObjectMapper mapper;
+    private final File file;
+
+    public JSONPersonalDatabase(String filename) {
+        this.file = new File(filename);
+        this.cache = new HashMap<>();
+        this.mapper = new ObjectMapper();
+
+        SimpleModule module = new SimpleModule();
+        module.addDeserializer(Course.class, new CourseIdDeserializer());
+        module.addSerializer(Course.class, new CourseIdSerializer());
+        mapper.registerModule(module);
+        mapper.setVisibility(PropertyAccessor.FIELD, JsonAutoDetect.Visibility.ANY);
+        mapper.registerModule(new ParameterNamesModule(JsonCreator.Mode.PROPERTIES));
+        mapper.registerModule(new JavaTimeModule());
+
+        try {
+            load();
+        } catch (IOException ex) {
+            throw new RuntimeException(ex);
+        }
+    }
+
+    private void load() throws IOException {
+        Golfer[] data = mapper.readValue(file, Golfer[].class);
+        cache.clear();
+        for (Golfer i : data) {
+            cache.put(i.getUsername(), i);
+        }
+    }
+
+    private void save() throws IOException {
+        Golfer[] data = cache.values().toArray(Golfer[]::new);
+        mapper.writer(new CustomPrettyPrinter()).writeValue(file, data);
+    }
+
+    @Override
+    public Golfer[] getGolfers() {
+        return new Golfer[0];
+    }
+
+    @Override
+    public Golfer getGolfer(String username) {
+        return cache.get(username);
+    }
+
+    @Override
+    public void addGolfer(Golfer golfer) throws IOException {
+        cache.put(golfer.getUsername(), golfer);
+        save();
+    }
+
+    @Override
+    public void removeGolfer(Golfer golfer) throws IOException {
+        cache.remove(golfer.getUsername());
+        save();
+    }
+
+    @Override
+    public void updateGolfer(Golfer golfer) throws IOException {
+        cache.put(golfer.getUsername(), golfer);
+        save();
+    }
+
+    private static class CourseIdSerializer extends JsonSerializer<Course> {
+        @Override
+        public void serialize(Course course, JsonGenerator gen, SerializerProvider serializers) throws IOException {
+            gen.writeNumber(course.getId());
+        }
+    }
+
+    private static class CourseIdDeserializer extends JsonDeserializer<Course> {
+        MasterDatabase masterDB = MasterDatabase.INSTANCE;
+
+        @Override
+        public Course deserialize(JsonParser p, DeserializationContext context) throws IOException {
+            int id = p.getValueAsInt();
+            return masterDB.getCourse(id);
+        }
+    }
+
+    private static class CustomPrettyPrinter extends DefaultPrettyPrinter {
+        public CustomPrettyPrinter() {
+            super._arrayIndenter = new DefaultIndenter();
+            super._objectFieldValueSeparatorWithSpaces = _separators.getObjectFieldValueSeparator() + " ";
+            super._arrayEmptySeparator = "";
+        }
+
+        @Override
+        public CustomPrettyPrinter createInstance() {
+            return new CustomPrettyPrinter();
+        }
+    }
+}