Rewrite Abacus to be the central class of the application.

src/org/nwapw/abacus/Abacus.java

@@ -1,46 +1,148 @@
 package org.nwapw.abacus;
 
-import org.nwapw.abacus.plugin.PluginManager;
+import org.nwapw.abacus.function.Operator;
-//import org.nwapw.abacus.plugin.StandardPlugin;
+import org.nwapw.abacus.number.NumberInterface;
-import org.nwapw.abacus.plugin.StandardPlugin;
-import org.nwapw.abacus.window.Window;
 import org.nwapw.abacus.plugin.ClassFinder;
+import org.nwapw.abacus.plugin.PluginListener;
+import org.nwapw.abacus.plugin.PluginManager;
+import org.nwapw.abacus.plugin.StandardPlugin;
+import org.nwapw.abacus.tree.NumberReducer;
+import org.nwapw.abacus.tree.TreeBuilder;
+import org.nwapw.abacus.tree.TreeNode;
+import org.nwapw.abacus.window.Window;
 
 import javax.swing.*;
 import java.io.IOException;
-import java.util.ArrayList;
 
-public class Abacus {
+/**
+ * The main calculator class. This is responsible
+ * for piecing together all of the components, allowing
+ * their interaction with each other.
+ */
+public class Abacus implements PluginListener {
 
+    /**
+     * The main Abacus UI.
+     */
     private Window mainUi;
-    private PluginManager manager;
+    /**
+     * The plugin manager responsible for
+     * loading and unloading plugins,
+     * and getting functions from them.
+     */
+    private PluginManager pluginManager;
+    /**
+     * Tree builder built from plugin manager,
+     * used to construct parse trees.
+     */
+    private TreeBuilder treeBuilder;
+    /**
+     * The reducer used to evaluate the tree.
+     */
+    private NumberReducer numberReducer;
 
+    /**
+     * Creates a new instance of the Abacus calculator.
+     */
     public Abacus(){
-        init();
+        pluginManager = new PluginManager(this);
+        mainUi = new Window(this);
+        numberReducer = new NumberReducer(this);
+
+        pluginManager.addListener(this);
+        pluginManager.addInstantiated(new StandardPlugin(pluginManager));
+        try {
+            ClassFinder.loadJars("plugins")
+                    .forEach(plugin -> pluginManager.addClass(plugin));
+        } catch (IOException | ClassNotFoundException e) {
+            e.printStackTrace();
+        }
+        pluginManager.load();
+
+        mainUi.setVisible(true);
     }
 
-    private void init() {
+    /**
+     * Gets the current tree builder.
+     * @return the main tree builder in this abacus instance.
+     */
+    public TreeBuilder getTreeBuilder() {
+        return treeBuilder;
+    }
+
+    /**
+     * Gets the current plugin manager,
+     * @return the plugin manager in this abacus instance.
+     */
+    public PluginManager getPluginManager() {
+        return pluginManager;
+    }
+
+    /**
+     * Gets the current UI.
+     * @return the UI window in this abacus instance.
+     */
+    public Window getMainUi() {
+        return mainUi;
+    }
+
+    /**
+     * Get the reducer that is responsible for transforming
+     * an expression into a number.
+     * @return the number reducer in this abacus instance.
+     */
+    public NumberReducer getNumberReducer() {
+        return numberReducer;
+    }
+
+    /**
+     * Parses a string into a tree structure using the main
+     * tree builder.
+     * @param input the input string to parse
+     * @return the resulting tree, null if the tree builder or the produced tree are null.
+     */
+    public TreeNode parseString(String input){
+        if(treeBuilder == null) return null;
+        return treeBuilder.fromString(input);
+    }
+
+    /**
+     * Evaluates the given tree using the main
+     * number reducer.
+     * @param tree the tree to reduce, must not be null.
+     * @return the resulting number, or null of the reduction failed.
+     */
+    public NumberInterface evaluateTree(TreeNode tree){
+        return tree.reduce(numberReducer);
+    }
+
+    @Override
+    public void onLoad(PluginManager manager) {
+        treeBuilder = new TreeBuilder();
+        for(String function : manager.getAllFunctions()){
+            treeBuilder.registerFunction(function);
+        }
+        for(String operator : manager.getAllOperators()){
+            Operator operatorObject = manager.operatorFor(operator);
+            treeBuilder.registerOperator(operator,
+                    operatorObject.getAssociativity(),
+                    operatorObject.getType(),
+                    operatorObject.getPrecedence());
+        }
+    }
+
+    @Override
+    public void onUnload(PluginManager manager) {
+        treeBuilder = null;
+    }
+
+    public static void main(String[] args){
         try {
             UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
         } catch (ClassNotFoundException | InstantiationException | UnsupportedLookAndFeelException | IllegalAccessException e) {
             e.printStackTrace();
         }
-        manager = new PluginManager();
-        manager.addInstantiated(new StandardPlugin(manager));
-        try {
-            ClassFinder.loadJars("plugins")
-                    .forEach(plugin -> manager.addClass(plugin));
-        } catch (IOException | ClassNotFoundException e) {
-            e.printStackTrace();
-        }
-        mainUi = new Window(manager);
-        mainUi.setVisible(true);
-        manager.load();
 
-    }
-
-    public static void main(String[] args){
         new Abacus();
     }
-
 }

src/org/nwapw/abacus/plugin/PluginManager.java

@@ -1,5 +1,6 @@
 package org.nwapw.abacus.plugin;
 
+import org.nwapw.abacus.Abacus;
 import org.nwapw.abacus.function.Function;
 import org.nwapw.abacus.function.Operator;
 
@@ -42,11 +43,17 @@ public class PluginManager {
      * The list of plugin listeners attached to this instance.
      */
     private Set<PluginListener> listeners;
+    /**
+     * The instance of Abacus that is used to interact with its other
+     * components.
+     */
+    private Abacus abacus;
 
     /**
      * Creates a new plugin manager.
      */
-    public PluginManager(){
+    public PluginManager(Abacus abacus){
+        this.abacus = abacus;
         loadedPluginClasses = new HashSet<>();
         plugins = new HashSet<>();
         cachedFunctions = new HashMap<>();

src/org/nwapw/abacus/tree/NumberReducer.java

@@ -1,8 +1,8 @@
 package org.nwapw.abacus.tree;
 
+import org.nwapw.abacus.Abacus;
 import org.nwapw.abacus.function.Function;
 import org.nwapw.abacus.number.NumberInterface;
-import org.nwapw.abacus.plugin.PluginManager;
 
 /**
  * A reducer implementation that turns a tree into a single number.
@@ -13,14 +13,14 @@ public class NumberReducer implements Reducer<NumberInterface> {
     /**
      * The plugin manager from which to draw the functions.
      */
-    private PluginManager manager;
+    private Abacus abacus;
 
     /**
-     * Creates a new number reducer with the given plugin manager.
+     * Creates a new number reducer.
-     * @param manager the plugin manager.
+     * @param abacus the calculator instance.
      */
-    public NumberReducer(PluginManager manager){
+    public NumberReducer(Abacus abacus){
-        this.manager = manager;
+        this.abacus = abacus;
     }
 
     @Override
@@ -30,12 +30,12 @@ public class NumberReducer implements Reducer<NumberInterface> {
         } else if(node instanceof BinaryInfixNode){
             NumberInterface left = (NumberInterface) children[0];
             NumberInterface right = (NumberInterface) children[1];
-            Function function = manager.operatorFor(((BinaryInfixNode) node).getOperation()).getFunction();
+            Function function = abacus.getPluginManager().operatorFor(((BinaryInfixNode) node).getOperation()).getFunction();
             if(function == null) return null;
             return function.apply(left, right);
         } else if(node instanceof UnaryPrefixNode) {
             NumberInterface child = (NumberInterface) children[0];
-            Function functionn = manager.operatorFor(((UnaryPrefixNode) node).getOperation()).getFunction();
+            Function functionn = abacus.getPluginManager().operatorFor(((UnaryPrefixNode) node).getOperation()).getFunction();
             if(functionn == null) return null;
             return functionn.apply(child);
         } else if(node instanceof FunctionNode){
@@ -43,7 +43,7 @@ public class NumberReducer implements Reducer<NumberInterface> {
             for(int i = 0; i < convertedChildren.length; i++){
                 convertedChildren[i] = (NumberInterface) children[i];
             }
-            Function function = manager.functionFor(((FunctionNode) node).getFunction());
+            Function function = abacus.getPluginManager().functionFor(((FunctionNode) node).getFunction());
             if(function == null) return null;
             return function.apply(convertedChildren);
         }

src/org/nwapw/abacus/window/Window.java

@@ -1,11 +1,7 @@
 package org.nwapw.abacus.window;
 
-import org.nwapw.abacus.function.Operator;
+import org.nwapw.abacus.Abacus;
 import org.nwapw.abacus.number.NumberInterface;
-import org.nwapw.abacus.plugin.PluginListener;
-import org.nwapw.abacus.plugin.PluginManager;
-import org.nwapw.abacus.tree.NumberReducer;
-import org.nwapw.abacus.tree.TreeBuilder;
 import org.nwapw.abacus.tree.TreeNode;
 
 import javax.swing.*;
@@ -18,7 +14,7 @@ import java.awt.event.MouseEvent;
 /**
  * The main UI window for the calculator.
  */
-public class Window extends JFrame implements PluginListener {
+public class Window extends JFrame {
 
     private static final String CALC_STRING = "Calculate";
     private static final String SYNTAX_ERR_STRING = "Syntax Error";
@@ -47,18 +43,10 @@ public class Window extends JFrame implements PluginListener {
     };
 
     /**
-     * The plugin manager used to retrieve functions.
+     * The instance of the Abacus class, used
+     * for interaction with plugins and configuration.
      */
-    private PluginManager manager;
+    private Abacus abacus;
-    /**
-     * The builder used to construct the parse trees.
-     */
-    private TreeBuilder builder;
-    /**
-     * The reducer used to evaluate the tree.
-     */
-    private NumberReducer reducer;
-
     /**
      * The last output by the calculator.
      */
@@ -130,15 +118,14 @@ public class Window extends JFrame implements PluginListener {
      * Action listener that causes the input to be evaluated.
      */
     private ActionListener evaluateListener = (event) -> {
-        if(builder == null) return;
+        TreeNode parsedExpression = abacus.parseString(inputField.getText());
-        TreeNode parsedExpression = builder.fromString(inputField.getText());
         if(parsedExpression == null){
             lastOutputArea.setText(SYNTAX_ERR_STRING);
             return;
         }
-        NumberInterface numberInterface = parsedExpression.reduce(reducer);
+        NumberInterface numberInterface = abacus.evaluateTree(parsedExpression);
-        if(numberInterface == null){
+        if(numberInterface == null) {
-            lastOutputArea.setText(EVAL_ERR_STRING);;
+            lastOutputArea.setText(EVAL_ERR_STRING);
             return;
         }
         lastOutput = numberInterface.toString();
@@ -159,13 +146,11 @@ public class Window extends JFrame implements PluginListener {
 
     /**
      * Creates a new window with the given manager.
-     * @param manager the manager to use.
+     * @param abacus the calculator instance to interact with other components.
      */
-    public Window(PluginManager manager){
+    public Window(Abacus abacus){
         this();
-        this.manager = manager;
+        this.abacus = abacus;
-        manager.addListener(this);
-        reducer = new NumberReducer(manager);
     }
 
     /**
@@ -261,23 +246,4 @@ public class Window extends JFrame implements PluginListener {
         });
     }
 
-    @Override
-    public void onLoad(PluginManager manager) {
-        builder = new TreeBuilder();
-        for(String function : manager.getAllFunctions()){
-            builder.registerFunction(function);
-        }
-        for(String operator : manager.getAllOperators()){
-            Operator operatorObject = manager.operatorFor(operator);
-            builder.registerOperator(operator,
-                    operatorObject.getAssociativity(),
-                    operatorObject.getType(),
-                    operatorObject.getPrecedence());
-        }
-    }
-
-    @Override
-    public void onUnload(PluginManager manager) {
-        builder = null;
-    }
 }