Implement a PluginLoader, which can load plugin jars.

src/org/nwapw/abacus/lexing/Lexer.java

@@ -54,7 +54,7 @@ public class Lexer<T> {
     /**
      * The registered patterns.
      */
-    private Map<PatternEntry<T>, Pattern<T>> patterns;
+    private HashMap<PatternEntry<T>, Pattern<T>> patterns;
 
     /**
      * Creates a new lexer with no registered patterns.
@@ -127,7 +127,7 @@ public class Lexer<T> {
      * @param compare the comparator used to sort matches by their IDs.
      * @return the resulting list of matches, in order, or null on error.
      */
-    public List<Match<T>> lexAll(String from, int startAt, Comparator<T> compare){
+    public ArrayList<Match<T>> lexAll(String from, int startAt, Comparator<T> compare){
         int index = startAt;
         ArrayList<Match<T>> matches = new ArrayList<>();
         Match<T> lastMatch = null;

src/org/nwapw/abacus/lexing/pattern/Pattern.java

@@ -2,7 +2,6 @@ package org.nwapw.abacus.lexing.pattern;
 
 import java.util.Collection;
 import java.util.HashMap;
-import java.util.Map;
 import java.util.Stack;
 import java.util.function.Function;
 
@@ -33,7 +32,7 @@ public class Pattern<T> {
      * A map of regex operator to functions that modify a PatternChain
      * with the appropriate operation.
      */
-    private Map<Character, Function<PatternChain<T>, PatternChain<T>>> operations =
+    private HashMap<Character, Function<PatternChain<T>, PatternChain<T>>> operations =
             new HashMap<Character, Function<PatternChain<T>, PatternChain<T>>>() {{
                 put('+', Pattern.this::transformPlus);
                 put('*', Pattern.this::transformStar);

src/org/nwapw/abacus/lexing/pattern/PatternNode.java

@@ -3,7 +3,6 @@ package org.nwapw.abacus.lexing.pattern;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.HashSet;
-import java.util.Set;
 
 /**
  * A base class for a pattern node. Provides all functions
@@ -17,7 +16,7 @@ public class PatternNode<T> {
      * The set of states to which the lexer should continue
      * should this node be correctly matched.
      */
-    protected Set<PatternNode<T>> outputStates;
+    protected HashSet<PatternNode<T>> outputStates;
 
     /**
      * Creates a new pattern node.

src/org/nwapw/abacus/number/NaiveNumber.java

@@ -88,9 +88,6 @@ public class NaiveNumber implements NumberInterface {
     @Override
     public NumberInterface promoteTo(Class<? extends NumberInterface> toClass) {
         if(toClass == this.getClass()) return this;
-        else if(toClass == PreciseNumber.class){
-            return new PreciseNumber(Double.toString(value));
-        }
         return null;
     }
 

src/org/nwapw/abacus/number/PreciseNumber.java

@@ -1,112 +0,0 @@
-package org.nwapw.abacus.number;
-
-import java.math.BigDecimal;
-import java.math.BigInteger;
-import java.math.MathContext;
-import java.math.RoundingMode;
-
-public class PreciseNumber implements NumberInterface{
-
-    /**
-     * The number one.
-     */
-    static final PreciseNumber ONE = new PreciseNumber(BigDecimal.ONE);
-    /**
-     * The number zero.
-     */
-    static final PreciseNumber ZERO = new PreciseNumber(BigDecimal.ZERO);
-    /**
-     * The number ten.
-     */
-    static final PreciseNumber TEN = new PreciseNumber(BigDecimal.TEN);
-
-    BigDecimal value = new BigDecimal("0");
-
-    /**
-     * Constructs a precise number from the given string.
-     * @param string a string representation of the number meeting the same conditions
-     *               as the BidDecimal(String) constructor.
-     */
-    public PreciseNumber(String string){
-        value = new BigDecimal(string);
-    }
-
-    /**
-     * Constructs a precise number from the given BigDecimal.
-     * @param value a BigDecimal object representing the value of the number.
-     */
-    public PreciseNumber(BigDecimal value){
-        this.value = value;
-    }
-
-    @Override
-    public int precision() {
-        return 54;
-    }
-
-    @Override
-    public NumberInterface multiply(NumberInterface multiplier) {
-        return new PreciseNumber(value.multiply(((PreciseNumber) multiplier).value));
-    }
-
-    @Override
-    public NumberInterface divide(NumberInterface divisor) {
-        return new PreciseNumber(value.divide(((PreciseNumber) divisor).value, this.precision(), RoundingMode.HALF_UP));
-    }
-
-    @Override
-    public NumberInterface add(NumberInterface summand) {
-        return new PreciseNumber(value.add(((PreciseNumber) summand).value));
-    }
-
-    @Override
-    public NumberInterface subtract(NumberInterface subtrahend) {
-        return new PreciseNumber(value.subtract(((PreciseNumber) subtrahend).value));
-    }
-
-    @Override
-    public NumberInterface intPow(int exponent) {
-        if(exponent == 0){
-            return PreciseNumber.ONE;
-        }
-        boolean takeReciprocal = exponent < 0;
-        exponent = Math.abs(exponent);
-        NumberInterface power = this;
-        for(int currentExponent = 1; currentExponent < exponent; currentExponent++){
-            power = power.multiply(this);
-        }
-        if(takeReciprocal){
-            power = PreciseNumber.ONE.divide(power);
-        }
-        return power;
-    }
-
-    @Override
-    public int compareTo(NumberInterface number) {
-        return value.compareTo(((PreciseNumber) number).value);
-    }
-
-    @Override
-    public int signum() {
-        return value.signum();
-    }
-
-    @Override
-    public NumberInterface negate(){
-        return new PreciseNumber(value.negate());
-    }
-
-    @Override
-    public NumberInterface promoteTo(Class<? extends NumberInterface> toClass) {
-        if(toClass == this.getClass()){
-            return this;
-        }
-        return null;
-    }
-
-    @Override
-    public String toString() {
-        BigDecimal rounded = value.setScale(precision() - 4, RoundingMode.HALF_UP);
-        return rounded.stripTrailingZeros().toPlainString();
-    }
-}

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

@@ -4,7 +4,6 @@ import org.nwapw.abacus.function.Function;
 import org.nwapw.abacus.function.Operator;
 
 import java.util.HashMap;
-import java.util.Map;
 import java.util.Set;
 
 /**
@@ -19,11 +18,11 @@ public abstract class Plugin {
     /**
      * A hash map of functions mapped to their string names.
      */
-    private Map<String, Function> functions;
+    private HashMap<String, Function> functions;
     /**
      * A hash map of operators mapped to their string names.
      */
-    private Map<String, Operator> operators;
+    private HashMap<String, Operator> operators;
     /**
      * The plugin manager in which to search for functions
      * not inside this package,

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

@@ -0,0 +1,106 @@
+package org.nwapw.abacus.plugin;
+
+import java.io.File;
+import java.io.IOException;
+import java.net.URL;
+import java.net.URLClassLoader;
+import java.util.ArrayList;
+import java.util.Properties;
+import java.util.jar.JarFile;
+
+/**
+ * A plugin loader, used to scan a directory for
+ * plugins and load them into classes that can then be
+ * used by the plugin manager.
+ */
+public class PluginLoader {
+
+    /**
+     * An internal class that represents a Jar file that
+     * has been founded, but not loaded.
+     */
+    private static final class PluginEntry {
+        String mainClass;
+        File jarPath;
+    }
+
+    /**
+     * The path which to search for plugins.
+     */
+    private File path;
+    /**
+     * The array of loaded plugin main classes.
+     */
+    private ArrayList<Class<?>> foundMainClasses;
+
+    /**
+     * Creates a new plugin loader at the given path.
+     * @param path the path which to search for plugins.
+     */
+    public PluginLoader(File path) {
+        this.path = path;
+    }
+
+    /**
+     * Loads all the plugin classes that have been found.
+     * @return the list of loaded classes.
+     * @throws IOException thrown when loading classes from URL fails.
+     * @throws ClassNotFoundException thrown when the class specified in plugin.properties is missing.
+     */
+    private ArrayList<Class<?>> loadPluginClasses() throws IOException, ClassNotFoundException {
+        ArrayList<Class<?>> foundMainClasses = new ArrayList<>();
+        for(PluginEntry entry : findPlugins()){
+            if(entry.mainClass == null) continue;
+            ClassLoader loader = URLClassLoader.newInstance(
+                    new URL[]{ entry.jarPath.toURI().toURL() },
+                    getClass().getClassLoader());
+            Class<?> loadedClass = loader.loadClass(entry.mainClass);
+            if(!Plugin.class.isAssignableFrom(loadedClass)) continue;
+            foundMainClasses.add(loadedClass);
+        }
+        return foundMainClasses;
+    }
+
+    /**
+     * Find all jars that have a plugin.properties file in the plugin folder.
+     * @return the list of all plugin entries, with their main class names and the jars files.
+     * @throws IOException thrown if reading the jar file fails
+     */
+    private ArrayList<PluginEntry> findPlugins() throws IOException {
+        ArrayList<PluginEntry> pluginEntries = new ArrayList<>();
+        File[] childFiles = path.listFiles();
+
+        if(childFiles == null) return pluginEntries;
+        for(File file : childFiles){
+            if(!file.isFile() || !file.getName().endsWith(".jar")) continue;
+            JarFile jarFile = new JarFile(file);
+            if(jarFile.getEntry("plugin.properties") == null) continue;
+            Properties properties = new Properties();
+            properties.load(jarFile.getInputStream(jarFile.getEntry("plugin.properties")));
+
+            PluginEntry entry = new PluginEntry();
+            entry.mainClass = properties.getProperty("mainClass");
+            entry.jarPath = file;
+            pluginEntries.add(entry);
+        }
+        return pluginEntries;
+    }
+
+    /**
+     * Loads all valid plugins and keeps track of them.
+     * @throws IOException thrown if loading from jar files fails.
+     * @throws ClassNotFoundException thrown if class specified in plugin.properties doesn't exist.
+     */
+    public void loadValidPlugins() throws IOException, ClassNotFoundException {
+        foundMainClasses = loadPluginClasses();
+    }
+
+    /**
+     * Gets the list of all the plugins that have last been loaded.
+     * @return the list of loaded class files.
+     */
+    public ArrayList<Class<?>> getFoundMainClasses() {
+        return foundMainClasses;
+    }
+
+}

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

@@ -15,29 +15,29 @@ public class PluginManager {
     /**
      * A list of loaded plugins.
      */
-    private List<Plugin> plugins;
+    private ArrayList<Plugin> plugins;
     /**
      * List of functions that have been cached,
      * that is, found in a plugin and returned.
      */
-    private Map<String, Function> cachedFunctions;
+    private HashMap<String, Function> cachedFunctions;
     /**
      * List of operators tha have been cached,
      * that is, found in a plugin and returned.
      */
-    private Map<String, Operator> cachedOperators;
+    private HashMap<String, Operator> cachedOperators;
     /**
      * List of all functions loaded by the plugins.
      */
-    private Set<String> allFunctions;
+    private HashSet<String> allFunctions;
     /**
      * List of all operators loaded by the plugins.
      */
-    private Set<String> allOperators;
+    private HashSet<String> allOperators;
     /**
      * The list of plugin listeners attached to this instance.
      */
-    private Set<PluginListener> listeners;
+    private HashSet<PluginListener> listeners;
 
     /**
      * Creates a new plugin manager.
@@ -155,7 +155,7 @@ public class PluginManager {
      * Gets all the functions loaded by the Plugin Manager.
      * @return the set of all functions that were loaded.
      */
-    public Set<String> getAllFunctions() {
+    public HashSet<String> getAllFunctions() {
         return allFunctions;
     }
 
@@ -163,7 +163,7 @@ public class PluginManager {
      * Gets all the operators loaded by the Plugin Manager.
      * @return the set of all operators that were loaded.
      */
-    public Set<String> getAllOperators() {
+    public HashSet<String> getAllOperators() {
         return allOperators;
     }
 

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

@@ -6,6 +6,9 @@ import org.nwapw.abacus.function.OperatorAssociativity;
 import org.nwapw.abacus.number.NaiveNumber;
 import org.nwapw.abacus.number.NumberInterface;
 
+import javax.print.attribute.standard.MediaSize;
+import java.util.ArrayList;
+import java.util.HashMap;
 import java.util.function.BiFunction;
 
 /**
@@ -228,7 +231,7 @@ public class StandardPlugin extends Plugin {
 
             @Override
             protected NumberInterface applyInternal(NumberInterface[] params) {
-                return StandardPlugin.this.getOperator("^").getFunction().apply(params[0], ((new NaiveNumber(0.5)).promoteTo(params[0].getClass())));
+                return StandardPlugin.this.getFunction("pow").apply(params[0], (new NaiveNumber(0.5)));
             }
         });
     }

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

@@ -1,7 +1,6 @@
 package org.nwapw.abacus.tree;
 
 import java.util.ArrayList;
-import java.util.List;
 
 /**
  * A node that represents a function call.
@@ -15,7 +14,7 @@ public class FunctionNode extends TreeNode {
     /**
      * The list of arguments to the function.
      */
-    private List<TreeNode> children;
+    private ArrayList<TreeNode> children;
 
     /**
      * Creates a function node with no function.

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

@@ -19,11 +19,11 @@ public class TreeBuilder {
     /**
      * The map of operator precedences.
      */
-    private Map<String, Integer> precedenceMap;
+    private HashMap<String, Integer> precedenceMap;
     /**
      * The map of operator associativity.
      */
-    private Map<String, OperatorAssociativity> associativityMap;
+    private HashMap<String, OperatorAssociativity> associativityMap;
 
     /**
      * Comparator used to sort token types.
@@ -70,7 +70,7 @@ public class TreeBuilder {
      * @param string the string to tokenize.
      * @return the list of tokens produced.
      */
-    public List<Match<TokenType>> tokenize(String string){
+    public ArrayList<Match<TokenType>> tokenize(String string){
         return lexer.lexAll(string, 0, tokenSorter);
     }
 
@@ -80,7 +80,7 @@ public class TreeBuilder {
      * @param from the tokens to be rearranged.
      * @return the resulting list of rearranged tokens.
      */
-    public List<Match<TokenType>> intoPostfix(String source, List<Match<TokenType>> from){
+    public ArrayList<Match<TokenType>> intoPostfix(String source, ArrayList<Match<TokenType>> from){
         ArrayList<Match<TokenType>> output = new ArrayList<>();
         Stack<Match<TokenType>> tokenStack = new Stack<>();
         while(!from.isEmpty()){
@@ -138,7 +138,7 @@ public class TreeBuilder {
      * @param matches the list of tokens from the source string.
      * @return the construct tree expression.
      */
-    public TreeNode fromStringRecursive(String source, List<Match<TokenType>> matches){
+    public TreeNode fromStringRecursive(String source, ArrayList<Match<TokenType>> matches){
         if(matches.size() == 0) return null;
         Match<TokenType> match = matches.remove(0);
         TokenType matchType = match.getType();
@@ -170,7 +170,7 @@ public class TreeBuilder {
      * @return the resulting tree.
      */
     public TreeNode fromString(String string){
-        List<Match<TokenType>> matches = tokenize(string);
+        ArrayList<Match<TokenType>> matches = tokenize(string);
         if(matches == null) return null;
         matches.removeIf(m -> m.getType() == TokenType.WHITESPACE);
         matches = intoPostfix(string, matches);

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

@@ -6,7 +6,6 @@ import javax.swing.event.TableModelListener;
 import javax.swing.table.AbstractTableModel;
 import javax.swing.table.TableModel;
 import java.util.ArrayList;
-import java.util.List;
 
 /**
  * A table model to store data about the history of inputs
@@ -58,7 +57,7 @@ public class HistoryTableModel extends AbstractTableModel {
     /**
      * The list of entries.
      */
-    List<HistoryEntry> entries;
+    ArrayList<HistoryEntry> entries;
 
     /**
      * Creates a new empty history table model