ldproxy · cportele · May 2, 2026 · May 8, 2026 · May 8, 2026 · May 9, 2026
@@ -240,7 +240,7 @@ protected FeatureQueryEncoder<String, QueryOptions> getQueryEncoder() {
         new QName(
             namespaceNormalizer.getNamespaceURI(namespaceNormalizer.extractURI(name)),
             namespaceNormalizer.getLocalName(name));
-    return new FeatureTokenDecoderGml(
+    return new FeatureTokenDecoderGmlFromWfs(
         namespaces,
         ImmutableList.of(qualifiedName),
         featureSchema,

@@ -32,9 +32,15 @@
 import javax.xml.stream.XMLStreamException;
 
 /**
+ * Decodes a streaming WFS response (a {@code wfs:FeatureCollection} of many features) into the
+ * platform's feature token stream. Path emission uses the qualified XML names directly, on the
+ * assumption that the consumer keys off XML-shaped paths (e.g. {@code adv:Flurstueck}, {@code
+ * gml:@id}). For consumers that key off the schema's property-name paths (e.g. the SQL feature
+ * encoder), use {@link FeatureTokenDecoderGml}.
+ *
  * @author zahnen
  */
-public class FeatureTokenDecoderGml
+public class FeatureTokenDecoderGmlFromWfs
     extends FeatureTokenDecoder<
         byte[], FeatureSchema, SchemaMapping, ModifiableContext<FeatureSchema, SchemaMapping>> {
 
@@ -59,7 +65,7 @@ public class FeatureTokenDecoderGml
   private OptionalInt srsDimension = OptionalInt.empty();
   private ModifiableContext<FeatureSchema, SchemaMapping> context;
 
-  public FeatureTokenDecoderGml(
+  public FeatureTokenDecoderGmlFromWfs(
       Map<String, String> namespaces,
       List<QName> featureTypes,
       FeatureSchema featureSchema,
@@ -122,7 +128,6 @@ private void feedInput(byte[] data) {
     }
   }
 
-  // TODO: single feature or collection
   protected boolean advanceParser() {
 
     boolean feedMeMore = false;

@@ -0,0 +1,105 @@
+/*
+ * Copyright 2025 interactive instruments GmbH
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+package de.ii.xtraplatform.features.gml.domain;
+
+/**
+ * Helpers for converting between {@code <gml:Circle>} (3 control points on a circle) and the
+ * 5-position closed CIRCULARSTRING representation used internally. The internal form satisfies
+ * {@code isClosed()} (first position equals last) so it passes ring-closure validation and is
+ * accepted as a full circle by PostGIS as {@code CIRCULARSTRING(P1, P2, P3, antipode(P2), P1)}.
+ *
+ * <p>Only 2D (XY) circles are handled; 3D circles would require resolving the circle's plane in
+ * 3-space and are not produced by current data.
+ */
+final class Circles {
+
+  private Circles() {}
+
+  /** Coordinate-unit tolerance for the {@link #isFullCircleClosed(double[])} check. */
+  private static final double EPS = 1.0e-6;
+
+  /** Determinant tolerance below which three points are treated as colinear. */
+  private static final double COLINEAR_EPS = 1.0e-12;
+
+  /**
+   * Expand the 3 control points of a {@code <gml:Circle>} into a 5-position closed CIRCULARSTRING:
+   * {@code (P1, P2, P3, antipode(P2), P1)}.
+   *
+   * @param xyP1P2P3 6 doubles: {@code x1, y1, x2, y2, x3, y3}
+   * @return 10 doubles: the 5 expanded positions
+   * @throws IllegalArgumentException if the three points are colinear (no circle is defined)
+   */
+  static double[] expandCircleToClosed(double[] xyP1P2P3) {
+    if (xyP1P2P3.length != 6) {
+      throw new IllegalArgumentException(
+          "expected exactly 3 XY positions (6 doubles), got " + xyP1P2P3.length);
+    }
+    double x1 = xyP1P2P3[0];
+    double y1 = xyP1P2P3[1];
+    double x2 = xyP1P2P3[2];
+    double y2 = xyP1P2P3[3];
+    double x3 = xyP1P2P3[4];
+    double y3 = xyP1P2P3[5];
+    double[] c = circumcenter(x1, y1, x2, y2, x3, y3);
+    double x4 = 2.0 * c[0] - x2;
+    double y4 = 2.0 * c[1] - y2;
+    return new double[] {x1, y1, x2, y2, x3, y3, x4, y4, x1, y1};
+  }
+
+  /**
+   * Test whether 5 closed positions form a full circle: positions 1, 2, 3 define a circle, the
+   * first and fifth positions coincide, and the fourth position is the antipode of the second
+   * position on that circle (all within {@link #EPS}).
+   *
+   * @param xy5positions 10 doubles: {@code x1, y1, x2, y2, x3, y3, x4, y4, x5, y5}
+   */
+  static boolean isFullCircleClosed(double[] xy5positions) {
+    if (xy5positions.length != 10) {
+      return false;
+    }
+    double x1 = xy5positions[0];
+    double y1 = xy5positions[1];
+    double x5 = xy5positions[8];
+    double y5 = xy5positions[9];
+    if (Math.abs(x1 - x5) > EPS || Math.abs(y1 - y5) > EPS) {
+      return false;
+    }
+    double x2 = xy5positions[2];
+    double y2 = xy5positions[3];
+    double x3 = xy5positions[4];
+    double y3 = xy5positions[5];
+    double x4 = xy5positions[6];
+    double y4 = xy5positions[7];
+    try {
+      double[] c = circumcenter(x1, y1, x2, y2, x3, y3);
+      double expectedX4 = 2.0 * c[0] - x2;
+      double expectedY4 = 2.0 * c[1] - y2;
+      return Math.abs(x4 - expectedX4) <= EPS && Math.abs(y4 - expectedY4) <= EPS;
+    } catch (IllegalArgumentException colinear) {
+      return false;
+    }
+  }
+
+  /**
+   * Circumcenter of three non-colinear 2D points.
+   *
+   * @throws IllegalArgumentException if the three points are colinear
+   */
+  static double[] circumcenter(double x1, double y1, double x2, double y2, double x3, double y3) {
+    double d = 2.0 * (x1 * (y2 - y3) + x2 * (y3 - y1) + x3 * (y1 - y2));
+    if (Math.abs(d) < COLINEAR_EPS) {
+      throw new IllegalArgumentException("three points are colinear; no circle is defined");
+    }
+    double s1 = x1 * x1 + y1 * y1;
+    double s2 = x2 * x2 + y2 * y2;
+    double s3 = x3 * x3 + y3 * y3;
+    double cx = (s1 * (y2 - y3) + s2 * (y3 - y1) + s3 * (y1 - y2)) / d;
+    double cy = (s1 * (x3 - x2) + s2 * (x1 - x3) + s3 * (x2 - x1)) / d;
+    return new double[] {cx, cy};
+  }
+}