From 8b6a4d174621bce3b68b8cff60be414daaaf891e Mon Sep 17 00:00:00 2001
From: Florian Steurer <florian.steurer95@gmail.com>
Date: Tue, 12 Apr 2016 11:28:07 +0200
Subject: [PATCH] refactoring and commenting

---
 .../unify/model/PlaceholderType.java          | 52 ++++++++++++++-----
 .../unify/model/ReferenceType.java            |  6 +++
 2 files changed, 45 insertions(+), 13 deletions(-)

diff --git a/src/de/dhbwstuttgart/typeinference/unify/model/PlaceholderType.java b/src/de/dhbwstuttgart/typeinference/unify/model/PlaceholderType.java
index 9b032b4a..01102fca 100644
--- a/src/de/dhbwstuttgart/typeinference/unify/model/PlaceholderType.java
+++ b/src/de/dhbwstuttgart/typeinference/unify/model/PlaceholderType.java
@@ -6,42 +6,68 @@ import java.util.Set;
 
 import de.dhbwstuttgart.typeinference.unify.interfaces.IFiniteClosure;
 
+/**
+ * An unbounded placeholder type.
+ * @author Florian Steurer
+ */
 public final class PlaceholderType extends UnifyType{
 	
+	/**
+	 * Static list containing the names of all existing placeholders.
+	 * Used for generating fresh placeholders.
+	 */
 	protected static final HashSet<String> EXISTING_PLACEHOLDERS = new HashSet<String>();
+	
+	/**
+	 * Prefix of auto-generated placeholder names.
+	 */
 	protected static String nextName = "gen_";
+	
+	/**
+	 * Random number generator used to generate fresh placeholder name.
+	 */
 	protected static Random rnd = new Random(43558747548978L);
 	
+	/**
+	 * True if this object was auto-generated, false if this object was user-generated.
+	 */
 	private final boolean IsGenerated;
 	
+	/**
+	 * Creates a new placeholder type with the specified name.
+	 */
 	public PlaceholderType(String name) {
 		super(name, new TypeParams());
-		EXISTING_PLACEHOLDERS.add(name);
-		IsGenerated = false;
+		EXISTING_PLACEHOLDERS.add(name); // Add to list of existing placeholder names
+		IsGenerated = false; // This type is user generated
 	}
 	
+	/**
+	 * Creates a new placeholdertype 
+	 * @param isGenerated true if this placeholder is auto-generated, false if it is user-generated.
+	 */
 	protected PlaceholderType(String name, boolean isGenerated) {
 		super(name, new TypeParams());
-		EXISTING_PLACEHOLDERS.add(name);
+		EXISTING_PLACEHOLDERS.add(name); // Add to list of existing placeholder names
 		IsGenerated = isGenerated;
 	}
 	
+	/**
+	 * Creates a fresh placeholder type with a name that does so far not exist.
+	 * A user could later instantiate a type using the same name that is equivalent to this type.
+	 * @return A fresh placeholder type.
+	 */
 	public static PlaceholderType freshPlaceholder() {
-		String name = nextName + randomChar();
-		
+		String name = nextName + (char) (rnd.nextInt(22) + 97); // Returns random char between 'a' and 'z'
+		// Add random chars while the name is in use.
 		while(EXISTING_PLACEHOLDERS.contains(name));
-			name += randomChar();
-			
+			name += (char) (rnd.nextInt(22) + 97); // Returns random char between 'a' and 'z'
 		return new PlaceholderType(name, true);
 	}
 	
 	/**
-	 * Returns random char between 'a' and 'z'
+	 * True if this placeholder is auto-generated, false if it is user-generated.
 	 */
-	private static char randomChar() {
-		return (char) (rnd.nextInt(22) + 97);
-	}
-	
 	public boolean isGenerated() {
 		return IsGenerated;
 	}
@@ -58,7 +84,7 @@ public final class PlaceholderType extends UnifyType{
 	
 	@Override
 	public UnifyType setTypeParams(TypeParams newTp) {
-		return this;
+		return this; // Placeholders never have params.
 	}
 	
 	@Override
diff --git a/src/de/dhbwstuttgart/typeinference/unify/model/ReferenceType.java b/src/de/dhbwstuttgart/typeinference/unify/model/ReferenceType.java
index 4f557b53..ad02c9ab 100644
--- a/src/de/dhbwstuttgart/typeinference/unify/model/ReferenceType.java
+++ b/src/de/dhbwstuttgart/typeinference/unify/model/ReferenceType.java
@@ -4,7 +4,13 @@ import java.util.Set;
 
 import de.dhbwstuttgart.typeinference.unify.interfaces.IFiniteClosure;
 
+/**
+ * A reference type e.q. Integer or List<T>.
+ * @author Florian Steurer
+ *
+ */
 public final class ReferenceType extends UnifyType {
+	
 	public ReferenceType(String name, UnifyType... typeParams) {
 		super(name, new TypeParams(typeParams));
 	}