added some comments

src/main/java/de/neemann/digital/analyse/expression/ComplexityInclNotVisitor.java

@@ -12,6 +12,11 @@ public class ComplexityInclNotVisitor implements ExpressionVisitor {
         return true;
     }
 
+    /**
+     * Returns a measure for the complexity of the examined expression
+     *
+     * @return the complexity
+     */
     public int getComplexity() {
         return counter;
     }

src/main/java/de/neemann/digital/analyse/expression/ComplexityVisitor.java

@@ -13,6 +13,12 @@ public class ComplexityVisitor implements ExpressionVisitor {
         return true;
     }
 
+    /**
+     * Returns a measure for the complexity of the examined expression
+     * The Not expression does not increase this complexity measure
+     *
+     * @return the complexity
+     */
     public int getComplexity() {
         return counter;
     }

src/main/java/de/neemann/digital/analyse/expression/Variable.java

@@ -9,10 +9,22 @@ public class Variable implements Comparable<Variable>, Expression {
 
     private String identifier;
 
+    /**
+     * Creates a new Variable
+     *
+     * @param name the variables name
+     * @return the new Variable
+     */
     public static Variable v(String name) {
         return new Variable(name);
     }
 
+    /**
+     * Creates an array of variables
+     *
+     * @param n the number of varfiables to create.
+     * @return variables named "A0", "A1", "A2" and so on
+     */
     public static ArrayList<Variable> vars(int n) {
         ArrayList<Variable> v = new ArrayList<Variable>();
         for (int i = 0; i < n; i++)
@@ -20,6 +32,12 @@ public class Variable implements Comparable<Variable>, Expression {
         return v;
     }
 
+    /**
+     * Create a list of variables using the given names
+     *
+     * @param names the names used to create the variables
+     * @return the list of variables
+     */
     public static ArrayList<Variable> vars(String... names) {
         ArrayList<Variable> v = new ArrayList<Variable>();
         for (String n : names)
@@ -27,10 +45,16 @@ public class Variable implements Comparable<Variable>, Expression {
         return v;
     }
 
+    /**
+     * Creates a new intsnce
+     *
+     * @param identifier the variables name
+     */
     public Variable(String identifier) {
         this.identifier = identifier;
     }
 
+    @Override
     public boolean calculate(Context context) throws ExpressionException {
         return context.get(this);
     }
@@ -46,6 +70,9 @@ public class Variable implements Comparable<Variable>, Expression {
         return identifier;
     }
 
+    /**
+     * @return the variables name
+     */
     public String getIdentifier() {
         return identifier;
     }

src/main/java/de/neemann/digital/analyse/expression/format/FormatterException.java

@@ -5,7 +5,7 @@ package de.neemann.digital.analyse.expression.format;
  *
  * @author hneemann
  */
-public class FormatterException extends Throwable {
+public class FormatterException extends Exception {
     /**
      * Creates a new instance
      *

src/main/java/de/neemann/digital/analyse/quinemc/BoolTableExpression.java

@@ -6,12 +6,20 @@ import de.neemann.digital.analyse.expression.Expression;
 import de.neemann.digital.analyse.expression.ExpressionException;
 
 /**
+ * Creates a bool table from the given expression
+ *
  * @author hneemann
  */
 public class BoolTableExpression implements BoolTable {
     private final Expression expression;
     private final ContextFiller context;
 
+    /**
+     * Creates a new instance
+     *
+     * @param expression the expression
+     * @param context    the context to evaluate the expression
+     */
     public BoolTableExpression(Expression expression, ContextFiller context) {
         this.expression = expression;
         this.context = context;

src/main/java/de/neemann/digital/analyse/quinemc/TableItem.java

@@ -6,7 +6,16 @@ package de.neemann.digital.analyse.quinemc;
  * @author hneemann
  */
 public enum TableItem {
+    /**
+     * Zero of false
+     */
     zero,
+    /**
+     * one or true
+     */
     one,
+    /**
+     * var is optimized
+     */
     optimized
 }

src/main/java/de/neemann/digital/analyse/quinemc/ThreeStateValue.java

@@ -4,11 +4,26 @@ package de.neemann.digital.analyse.quinemc;
  * @author hneemann
  */
 public enum ThreeStateValue {
+    /**
+     * one or true
+     */
     one,
+    /**
+     * zero or false
+     */
     zero,
+    /**
+     * dont care
+     */
     dontCare;
 
 
+    /**
+     * Create a value from a bool
+     *
+     * @param bool the bool
+     * @return the created ThreeStateValue
+     */
     public static ThreeStateValue value(boolean bool) {
         if (bool) {
             return one;
@@ -17,6 +32,13 @@ public enum ThreeStateValue {
         }
     }
 
+    /**
+     * Create a value from an int
+     * 0 and 1 work as expected, any other value means "dont care"
+     *
+     * @param value the value
+     * @return the created ThreeStateValue
+     */
     public static ThreeStateValue value(int value) {
         switch (value) {
             case 0: