From a1a67b3a7c0b8291cc822f69552cbebe272750c1 Mon Sep 17 00:00:00 2001
From: qvalentin <valentin.theodor@web.de>
Date: Fri, 22 Apr 2022 10:30:06 +0200
Subject: [PATCH] Add Generic way of calling Persistence Adapter when the state
 of a set changes

---
 .../src/main/java/abstraction/CustomSet.java  | 17 +++++++
 .../CustomSetPersistenceDecorator.java        | 43 +++++++++++++++++
 .../java/abstraction/CustomStrictSet.java     | 47 +++++++++++++++++++
 .../java/abstraction/PersistenceAdapter.java  | 11 +++++
 .../category/CategoryPersistenceAdapter.java  | 10 ----
 .../java/link/LinkPersistenceAdapter.java     | 10 ----
 6 files changed, 118 insertions(+), 20 deletions(-)
 create mode 100644 3-Domain/src/main/java/abstraction/CustomSet.java
 create mode 100644 3-Domain/src/main/java/abstraction/CustomSetPersistenceDecorator.java
 create mode 100644 3-Domain/src/main/java/abstraction/CustomStrictSet.java
 create mode 100644 3-Domain/src/main/java/abstraction/PersistenceAdapter.java
 delete mode 100644 3-Domain/src/main/java/category/CategoryPersistenceAdapter.java
 delete mode 100644 3-Domain/src/main/java/link/LinkPersistenceAdapter.java

diff --git a/3-Domain/src/main/java/abstraction/CustomSet.java b/3-Domain/src/main/java/abstraction/CustomSet.java
new file mode 100644
index 0000000..43a7fc5
--- /dev/null
+++ b/3-Domain/src/main/java/abstraction/CustomSet.java
@@ -0,0 +1,17 @@
+package abstraction;
+
+import java.util.Set;
+import java.util.stream.Stream;
+
+public interface CustomSet<T> {
+
+
+
+	Stream<T> stream();
+
+	boolean add(T value);
+
+	boolean remove(T value);
+
+	Set<T> getSet();
+}
diff --git a/3-Domain/src/main/java/abstraction/CustomSetPersistenceDecorator.java b/3-Domain/src/main/java/abstraction/CustomSetPersistenceDecorator.java
new file mode 100644
index 0000000..c81d5dd
--- /dev/null
+++ b/3-Domain/src/main/java/abstraction/CustomSetPersistenceDecorator.java
@@ -0,0 +1,43 @@
+package abstraction;
+
+import java.util.Set;
+import java.util.stream.Stream;
+
+/**
+ * A Decorator to intercept all state changes on a set and sync them with the persistence layer of the
+ * application.
+ * @param <T> The data type that should be stored and updated in the persistence layer
+ */
+public class CustomSetPersistenceDecorator<T> implements CustomSet<T> {
+
+	private final CustomSet<T> set;
+	private final PersistenceAdapter<T> persistenceAdapter;
+
+	public CustomSetPersistenceDecorator(PersistenceAdapter<T> persistenceAdapter) {
+		this.persistenceAdapter = persistenceAdapter;
+		this.set = new CustomStrictSet(persistenceAdapter.getAll());
+	}
+
+	@Override
+	public Stream<T> stream(){
+		return set.stream();
+	}
+
+	@Override
+	public boolean add(T value){
+		persistenceAdapter.add(value);
+		return set.add(value);
+	}
+
+	@Override
+	public boolean remove(T value) {
+		persistenceAdapter.remove(value);
+		return this.set.remove(value);
+	}
+
+	@Override
+	public Set<T> getSet() {
+		return this.set.getSet();
+	}
+
+}
diff --git a/3-Domain/src/main/java/abstraction/CustomStrictSet.java b/3-Domain/src/main/java/abstraction/CustomStrictSet.java
new file mode 100644
index 0000000..e67c5ab
--- /dev/null
+++ b/3-Domain/src/main/java/abstraction/CustomStrictSet.java
@@ -0,0 +1,47 @@
+package abstraction;
+
+import exeptions.ElementAlreadyInSet;
+import exeptions.ElementNotInSet;
+
+import java.util.Set;
+import java.util.stream.Stream;
+
+public class CustomStrictSet<T> implements CustomSet<T> {
+
+	private final Set<T> set;
+
+	public CustomStrictSet(Set<T> set) {
+		this.set = set;
+	}
+
+	@Override
+	public Stream<T> stream() {
+		return this.set.stream();
+	}
+
+	@Override
+	public Set<T> getSet() {
+		return this.set;
+	}
+
+	@Override
+	public boolean add(T value) {
+
+		if (this.set.contains(value)) {
+			throw new ElementAlreadyInSet("Tried adding " + value + " of class " + value
+					.getClass()
+					.getName() + " but the set already contains it.");
+		}
+		return this.set.add(value);
+	}
+
+	@Override
+	public boolean remove(T value) {
+		if (!this.set.contains(value)) {
+			throw new ElementNotInSet("Tried removing " + value + " of class " + value
+					.getClass()
+					.getName() + " but the set not contains it.");
+		}
+		return this.set.remove(value);
+	}
+}
diff --git a/3-Domain/src/main/java/abstraction/PersistenceAdapter.java b/3-Domain/src/main/java/abstraction/PersistenceAdapter.java
new file mode 100644
index 0000000..98ee6b8
--- /dev/null
+++ b/3-Domain/src/main/java/abstraction/PersistenceAdapter.java
@@ -0,0 +1,11 @@
+package abstraction;
+
+import java.util.Set;
+
+public interface PersistenceAdapter<T> {
+
+	Set<T> getAll();
+	Boolean add(T value);
+	Boolean remove(T value);
+
+}
diff --git a/3-Domain/src/main/java/category/CategoryPersistenceAdapter.java b/3-Domain/src/main/java/category/CategoryPersistenceAdapter.java
deleted file mode 100644
index 75783e8..0000000
--- a/3-Domain/src/main/java/category/CategoryPersistenceAdapter.java
+++ /dev/null
@@ -1,10 +0,0 @@
-package category;
-
-import java.util.Set;
-
-public interface CategoryPersistenceAdapter {
-
-	Set<Category> getAll();
-	Boolean add(Category category);
-
-}
diff --git a/3-Domain/src/main/java/link/LinkPersistenceAdapter.java b/3-Domain/src/main/java/link/LinkPersistenceAdapter.java
deleted file mode 100644
index a945e7b..0000000
--- a/3-Domain/src/main/java/link/LinkPersistenceAdapter.java
+++ /dev/null
@@ -1,10 +0,0 @@
-package link;
-
-import java.util.Set;
-
-public interface LinkPersistenceAdapter {
-
-	Set<Link> getAll();
-	Boolean add(Link link);
-
-}