Implement a table as a history tracker.

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

@@ -0,0 +1,97 @@
+package org.nwapw.abacus.window;
+
+import org.nwapw.abacus.tree.TreeNode;
+
+import javax.swing.event.TableModelListener;
+import javax.swing.table.AbstractTableModel;
+import javax.swing.table.TableModel;
+import java.util.ArrayList;
+
+public class HistoryTableModel extends AbstractTableModel {
+
+    public static final String[] COLUMN_NAMES = {
+            "Input",
+            "Parsed Input",
+            "Output"
+    };
+
+    public static final Class[] CLASS_TYPES = {
+            String.class,
+            TreeNode.class,
+            String.class
+    };
+
+    public static class HistoryEntry {
+        public String input;
+        public TreeNode parsedInput;
+        public String output;
+
+        public HistoryEntry(String input, TreeNode parsedInput, String output){
+            this.input = input;
+            this.parsedInput = parsedInput;
+            this.output = output;
+        }
+
+        Object nthValue(int n){
+            if(n == 0) return input;
+            if(n == 1) return parsedInput;
+            if(n == 2) return output;
+            return null;
+        }
+    }
+
+    ArrayList<HistoryEntry> entries;
+
+    public HistoryTableModel() {
+        entries = new ArrayList<>();
+    }
+
+    public void addEntry(HistoryEntry entry){
+        entries.add(entry);
+    }
+
+        @Override
+    public int getRowCount() {
+        return entries.size();
+    }
+
+    @Override
+    public int getColumnCount() {
+        return 3;
+    }
+
+    @Override
+    public String getColumnName(int columnIndex) {
+        return COLUMN_NAMES[columnIndex];
+    }
+
+    @Override
+    public Class<?> getColumnClass(int columnIndex) {
+        return CLASS_TYPES[columnIndex];
+    }
+
+    @Override
+    public boolean isCellEditable(int rowIndex, int columnIndex) {
+        return false;
+    }
+
+    @Override
+    public Object getValueAt(int rowIndex, int columnIndex) {
+        return entries.get(rowIndex).nthValue(columnIndex);
+    }
+
+    @Override
+    public void setValueAt(Object aValue, int rowIndex, int columnIndex) {
+        return;
+    }
+
+    @Override
+    public void addTableModelListener(TableModelListener l) {
+
+    }
+
+    @Override
+    public void removeTableModelListener(TableModelListener l) {
+
+    }
+}