✨ allow sending multiple anchors when building line items (#170)

Author: ianardee

src/main/java/com/mindee/parsing/custom/lineitems/LineGenerator.java

@@ -4,9 +4,11 @@
 import com.mindee.geometry.BboxUtils;
 import com.mindee.parsing.custom.ListField;
 import com.mindee.parsing.custom.ListFieldValue;
+import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collection;
 import java.util.HashMap;
+import java.util.List;
 import java.util.Map;
 import org.apache.commons.math3.util.Precision;
 
@@ -19,38 +21,53 @@ public final class LineGenerator {
   private LineGenerator() {
   }
 
-  public static Collection<Line> prepareLines(
+  public static PreparedLines prepareLines(
       Map<String, ListField> fields,
-      Anchor fieldAsAnchor
+      List<Anchor> anchors
   ) {
-    HashMap<Integer, Line> table = new HashMap<>();
-
-    ListField anchor = fields.get(fieldAsAnchor.getName());
-
-    if (anchor == null) {
-      throw new IllegalStateException("The field selected for the anchor was not found.");
+    Anchor bestAnchor = null;
+    Collection<Line> lines = null;
+    int lineCount = 0;
+    for (Anchor anchor : anchors) {
+      ListField anchorColumn = fields.get(anchor.getName());
+      if (anchorColumn == null) {
+        throw new IllegalStateException("The field selected for the anchor was not found.");
+      }
+      Collection<Line> currentLines = createLines(
+          anchorColumn.getValues(),
+          anchor.getTolerance()
+      );
+      if (currentLines.size() > lineCount) {
+        bestAnchor = anchor;
+        lines = currentLines;
+        lineCount = currentLines.size();
+      }
     }
-
-    if (anchor.getValues().isEmpty()) {
-      throw new IllegalStateException("No lines have been detected.");
+    if (lines == null) {
+      throw new IllegalStateException("Could not determine which anchor to use.");
     }
+    return new PreparedLines(
+        bestAnchor,
+        new ArrayList<>(lines)
+    );
+  }
+
+  private static Collection<Line> createLines(List<ListFieldValue> anchorValues, double tolerance) {
+    HashMap<Integer, Line> table = new HashMap<>();
 
     // handle one value and the case of one line
     int lineNumber = 1;
-    Line currentLine = new Line(lineNumber, fieldAsAnchor.getTolerance());
-    ListFieldValue currentValue = anchor.getValues().get(0);
+    Line currentLine = new Line(lineNumber, tolerance);
+    ListFieldValue currentValue = anchorValues.get(0);
     currentLine.setBbox(currentValue.getPolygon().getAsBbox());
-
-    for (int i = 1; i < anchor.getValues().size(); i++) {
-
-      currentValue = anchor.getValues().get(i);
+    for (ListFieldValue anchorValue : anchorValues) {
+      currentValue = anchorValue;
       Bbox currentFieldBbox = currentValue.getPolygon().getAsBbox();
-
       if (
           Precision.equals(
             currentLine.getBbox().getMinY(),
             currentFieldBbox.getMinY(),
-            fieldAsAnchor.getTolerance()
+            tolerance
           )
       ) {
         currentLine.setBbox(
@@ -60,13 +77,11 @@ public static Collection<Line> prepareLines(
         // when it is a new line
         table.put(lineNumber, currentLine);
         lineNumber++;
-        currentLine = new Line(lineNumber, fieldAsAnchor.getTolerance());
+        currentLine = new Line(lineNumber, tolerance);
         currentLine.setBbox(currentFieldBbox);
       }
     }
-
     table.putIfAbsent(lineNumber, currentLine);
-
     return table.values();
   }
 

src/main/java/com/mindee/parsing/custom/lineitems/LineItemsGenerator.java

@@ -1,10 +1,10 @@
 package com.mindee.parsing.custom.lineitems;
 
 import com.mindee.geometry.MinMax;
-import com.mindee.geometry.PolygonUtils;
 import com.mindee.parsing.custom.ListField;
 import com.mindee.parsing.custom.ListFieldValue;
 import java.util.ArrayList;
+import java.util.Collections;
 import java.util.List;
 import java.util.Map;
 import java.util.stream.Collectors;
@@ -19,8 +19,25 @@ private LineItemsGenerator() {
   }
 
   /**
-   * WARNING: This feature is experimental!
-   * Results may not always work as intended.
+   * Generate line items.
+   * Use this method if you want to send a list of different possible anchor fields.
+   * Will use the tolerance settings from the best anchor.
+   */
+  public static LineItems generate(
+      List<String> fieldNames,
+      Map<String, ListField> fields,
+      List<Anchor> anchors
+  ) {
+    Map<String, ListField> fieldsToTransformIntoLines = fields.entrySet()
+        .stream()
+        .filter(field -> fieldNames.contains(field.getKey()))
+        .collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue));
+    return generate(fieldsToTransformIntoLines, anchors);
+  }
+
+  /**
+   * Generate line items.
+   * Use this method if you want to use a single anchor field.
    */
   public static LineItems generate(
       List<String> fieldNames,
@@ -31,20 +48,32 @@ public static LineItems generate(
         .stream()
         .filter(field -> fieldNames.contains(field.getKey()))
         .collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue));
+    List<Anchor> anchors = new ArrayList<>(
+        Collections.singletonList(anchor)
+    );
+    return generate(fieldsToTransformIntoLines, anchors);
+  }
 
+  private static LineItems generate(
+      Map<String, ListField> fieldsToTransformIntoLines,
+      List<Anchor> anchors
+  ) {
+    PreparedLines preparedLines = LineGenerator.prepareLines(
+        fieldsToTransformIntoLines,
+        anchors
+    );
     List<Line> lines = populateLines(
         fieldsToTransformIntoLines,
-        new ArrayList<>(LineGenerator.prepareLines(fieldsToTransformIntoLines, anchor)),
-        anchor.getTolerance()
+        preparedLines.getLines(),
+        preparedLines.getAnchor().getTolerance()
     );
-
     return new LineItems(lines);
   }
 
   private static List<Line> populateLines(
       Map<String, ListField> fields,
       List<Line> lines,
-      double heightLineTolerance
+      double tolerance
   ) {
     List<Line> populatedLines = new ArrayList<>();
 
@@ -54,8 +83,8 @@ private static List<Line> populateLines(
           MinMax minMaxY = listFieldValue.getPolygon().getMinMaxY();
 
           if (
-              Math.abs(minMaxY.getMax() - currentLine.getBbox().getMaxY()) <= heightLineTolerance
-              && Math.abs(minMaxY.getMin() - currentLine.getBbox().getMinY()) <= heightLineTolerance
+              Math.abs(minMaxY.getMax() - currentLine.getBbox().getMaxY()) <= tolerance
+              && Math.abs(minMaxY.getMin() - currentLine.getBbox().getMinY()) <= tolerance
           ) {
             currentLine.addField(field.getKey(), listFieldValue);
           }

src/main/java/com/mindee/parsing/custom/lineitems/PreparedLines.java

@@ -0,0 +1,21 @@
+package com.mindee.parsing.custom.lineitems;
+
+import java.util.List;
+import lombok.Getter;
+
+/**
+ * An anchor and its initial lines.
+ */
+@Getter
+public final class PreparedLines {
+  private final Anchor anchor;
+  private final List<Line> lines;
+
+  /**
+   * An anchor and its initial lines.
+   */
+  public PreparedLines(Anchor anchor, List<Line> lines) {
+    this.anchor = anchor;
+    this.lines = lines;
+  }
+}