From a453a01ff9fe47e2b0146b6d8695595d17658b01 Mon Sep 17 00:00:00 2001
From: qvalentin <valentin.theodor@web.de>
Date: Fri, 22 Apr 2022 16:41:20 +0200
Subject: [PATCH] Add generic DAO with CSV implementation

---
 .../main/java/persistence/GenericCSVDAO.java  | 71 +++++++++++++++++++
 .../src/main/java/persistence/GenericDAO.java | 16 +++++
 .../java/persistence/csv/CSVSerializable.java | 10 +++
 3 files changed, 97 insertions(+)
 create mode 100644 0-Plugin/src/main/java/persistence/GenericCSVDAO.java
 create mode 100644 1-Adapter/src/main/java/persistence/GenericDAO.java
 create mode 100644 1-Adapter/src/main/java/persistence/csv/CSVSerializable.java

diff --git a/0-Plugin/src/main/java/persistence/GenericCSVDAO.java b/0-Plugin/src/main/java/persistence/GenericCSVDAO.java
new file mode 100644
index 0000000..6c02bfd
--- /dev/null
+++ b/0-Plugin/src/main/java/persistence/GenericCSVDAO.java
@@ -0,0 +1,71 @@
+package persistence;
+
+import persistence.csv.CSVSerializable;
+
+import java.io.BufferedReader;
+import java.io.BufferedWriter;
+import java.io.File;
+import java.io.FileReader;
+import java.io.FileWriter;
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Set;
+import java.util.function.Function;
+import java.util.stream.Collectors;
+
+public class GenericCSVDAO<T extends CSVSerializable> implements GenericDAO<T> {
+
+	private final File file;
+	private final Function<String[], T> constructor;
+
+	public GenericCSVDAO(File file, Function<String[], T> constructor) {
+		this.file = file;
+		this.constructor = constructor;
+	}
+
+	public Set<T> getALl() {
+		var lines = new ArrayList<String>();
+		try (BufferedReader br = new BufferedReader(new FileReader(this.file))) {
+			for (String line; (line = br.readLine()) != null; ) {
+				lines.add(line);
+			}
+		}
+		catch (IOException e) {
+			e.printStackTrace();
+		}
+
+		return lines
+				.stream()
+				.map(line -> constructor.apply(line.split(CSVSerializable.seperator)))
+				.collect(Collectors.toSet());
+	}
+
+	@Override
+	public void remove(T value) {
+		var allEntities = this.getALl();
+		this.removeAll();
+
+		allEntities.stream().filter(entity -> !entity.equals(value)).forEach(this::add);
+	}
+
+	@Override
+	public void add(T value) {
+		try (BufferedWriter bufferedWriter = new BufferedWriter(new FileWriter(this.file, true))) {
+			bufferedWriter.write(value.toCSVString());
+			bufferedWriter.newLine();
+		}
+		catch (IOException e) {
+			e.printStackTrace();
+		}
+	}
+
+	public void removeAll() {
+
+		try (BufferedWriter bufferedWriter = new BufferedWriter(new FileWriter(this.file, true))) {
+			bufferedWriter.write("");
+		}
+		catch (IOException e) {
+			e.printStackTrace();
+		}
+	}
+}
diff --git a/1-Adapter/src/main/java/persistence/GenericDAO.java b/1-Adapter/src/main/java/persistence/GenericDAO.java
new file mode 100644
index 0000000..8817996
--- /dev/null
+++ b/1-Adapter/src/main/java/persistence/GenericDAO.java
@@ -0,0 +1,16 @@
+package persistence;
+
+import persistence.category.CategoryEntity;
+
+import java.util.Set;
+import java.util.function.Function;
+
+public interface GenericDAO<T> {
+
+	public Set<T> getALl();
+
+	void remove(T value);
+
+	void add(T value);
+
+}
diff --git a/1-Adapter/src/main/java/persistence/csv/CSVSerializable.java b/1-Adapter/src/main/java/persistence/csv/CSVSerializable.java
new file mode 100644
index 0000000..48e2020
--- /dev/null
+++ b/1-Adapter/src/main/java/persistence/csv/CSVSerializable.java
@@ -0,0 +1,10 @@
+package persistence.csv;
+
+public interface CSVSerializable {
+
+	static String seperator = ",";
+
+	String[] getHeaders();
+
+	String toCSVString();
+}