add collapsing

app/src/main/java/org/agp8x/android/games/fillgrid/data/Cell.java

@@ -6,4 +6,6 @@ package org.agp8x.android.games.fillgrid.data;
 
 public interface Cell {
     String getTableSymbol();
+
+    void markCollapsed();
 }

app/src/main/java/org/agp8x/android/games/fillgrid/data/GridBoard.java

@@ -1,6 +1,8 @@
 package org.agp8x.android.games.fillgrid.data;
 
 import java.util.HashMap;
+import java.util.LinkedList;
+import java.util.List;
 import java.util.Map;
 import java.util.Objects;
 
@@ -43,6 +45,61 @@ public class GridBoard<G extends GridObject<C>, C extends Cell> implements Grid<
         contents.clear();
     }
 
+    /**
+     * Find lines with all cells filled and mark them as collapsed
+     *
+     * @return number of collapsed cells
+     */
+    public int collapseFilledLines() {
+        List<Offset> deletionQueue = findFullLines();
+        deletionQueue.stream().map(contents::get).forEach(Cell::markCollapsed);
+        return deletionQueue.size();
+    }
+
+    public List<Offset> findFullLines() {
+        List<Offset> offsets = new LinkedList<>();
+        offsets.addAll(findFullLines(dimensions.x, dimensions.y, new HorizontalLine()));
+        offsets.addAll(findFullLines(dimensions.y, dimensions.x, new VerticalLine()));
+        return offsets;
+    }
+
+    private List<Offset> findFullLines(int limit0, int limit1, OffsetLineGenerator offset) {
+        List<Offset> offsets = new LinkedList<>();
+        for (int i = 0; i < limit0; i++) {
+            List<Offset> line = new LinkedList<>();
+            for (int j = 0; j < limit1; j++) {
+                Offset key = offset.build(i, j);
+                if (contents.containsKey(key) && contents.get(key) != null) {
+                    line.add(key);
+                } else {
+                    break;
+                }
+            }
+            if (line.size() == dimensions.y) {
+                offsets.addAll(line);
+            }
+        }
+        return offsets;
+    }
+
+    private interface OffsetLineGenerator {
+        Offset build(int x, int y);
+    }
+
+    private class HorizontalLine implements OffsetLineGenerator {
+        @Override
+        public Offset build(int x, int y) {
+            return new Offset(y, x);
+        }
+    }
+
+    private class VerticalLine implements OffsetLineGenerator {
+        @Override
+        public Offset build(int x, int y) {
+            return new Offset(x, y);
+        }
+    }
+
     /**
      * Check whether a given object can be placed on a given origin
      *

app/src/main/java/org/agp8x/android/games/fillgrid/data/StringCell.java

@@ -30,4 +30,9 @@ public class StringCell implements Cell {
     public String getTableSymbol() {
         return value.substring(0,1);
     }
+
+    @Override
+    public void markCollapsed() {
+
+    }
 }

app/src/test/java/org/agp8x/android/games/fillgrid/data/GridBoardTest.java

@@ -38,5 +38,25 @@ public class GridBoardTest {
         System.out.println(board.symbolTable());
         board.drop(new Offset(3,0), block1);
         System.out.println(board.symbolTable());
+        System.out.println(board.findFullLines());
+        GridBlock<StringCell> block2 = new GridBlock<>(new HashMap<>());
+        block2.getObjects().put(new Offset(1,0), new StringCell("F"));
+        board.drop(new Offset(0,0), block2);
+        System.out.println(board.symbolTable());
+        System.out.println(board.findFullLines());
+    }
+
+    @Test
+    public void testFullLines() throws Exception {
+        GridBlock<StringCell> block1 = new GridBlock<>(new HashMap<>());
+        block1.getObjects().put(new Offset(0,0), new StringCell("1"));
+        block1.getObjects().put(new Offset(0,1), new StringCell("2"));
+        block1.getObjects().put(new Offset(0,2), new StringCell("3"));
+        block1.getObjects().put(new Offset(0,3), new StringCell("4"));
+        board.drop(new Offset(0,0), block1);
+        System.out.println(board.symbolTable());
+        System.out.println(board.findFullLines());
+        System.out.println(board.collapseFilledLines());
+
     }
 }