feat: Add support of multiple image occurrences

src/main/java/io/appium/java_client/imagecomparison/OccurrenceMatchingOptions.java

@@ -24,6 +24,8 @@
 
 public class OccurrenceMatchingOptions extends BaseComparisonOptions<OccurrenceMatchingOptions> {
     private Double threshold;
+    private Boolean multiple;
+    private Integer matchNeighbourThreshold;
 
     /**
      * At what normalized threshold to reject an occurrence.
@@ -36,11 +38,38 @@ public OccurrenceMatchingOptions withThreshold(double threshold) {
         return this;
     }
 
+    /**
+     * Whether to enable the support of multiple image occurrences.
+     *
+     * @since Appium 1.21.0
+     * @return self instance for chaining.
+     */
+    public OccurrenceMatchingOptions enableMultiple() {
+        this.multiple = true;
+        return this;
+    }
+
+    /**
+     * The pixel distance between matches we consider
+     * to be part of the same template match. This option is only
+     * considered if multiple matches mode is enabled.
+     * 10 pixels by default.
+     *
+     * @since Appium 1.21.0
+     * @return self instance for chaining.
+     */
+    public OccurrenceMatchingOptions withMatchNeighbourThreshold(int threshold) {
+        this.matchNeighbourThreshold = threshold;
+        return this;
+    }
+
     @Override
     public Map<String, Object> build() {
         final ImmutableMap.Builder<String, Object> builder = ImmutableMap.builder();
         builder.putAll(super.build());
         ofNullable(threshold).map(x -> builder.put("threshold", x));
+        ofNullable(matchNeighbourThreshold).map(x -> builder.put("matchNeighbourThreshold", x));
+        ofNullable(multiple).map(x -> builder.put("multiple", x));
         return builder.build();
     }
 }

src/main/java/io/appium/java_client/imagecomparison/OccurrenceMatchingResult.java

@@ -18,13 +18,23 @@
 
 import org.openqa.selenium.Rectangle;
 
+import java.util.List;
 import java.util.Map;
+import java.util.stream.Collectors;
 
 public class OccurrenceMatchingResult extends ComparisonResult {
     private static final String RECT = "rect";
+    private static final String MULTIPLE = "multiple";
+
+    private final boolean isAtRoot;
 
     public OccurrenceMatchingResult(Map<String, Object> input) {
+        this(input, true);
+    }
+
+    private OccurrenceMatchingResult(Map<String, Object> input, boolean isAtRoot) {
         super(input);
+        this.isAtRoot = isAtRoot;
     }
 
     /**
@@ -37,4 +47,25 @@ public Rectangle getRect() {
         //noinspection unchecked
         return mapToRect((Map<String, Object>) getCommandResult().get(RECT));
     }
+
+    /**
+     * Returns the list of multiple matches (if any).
+     * This property only works if the `multiple` option is enabled.
+     *
+     * @since Appium 1.21.0
+     * @return The list containing properties of each single match or an empty list.
+     * @throws IllegalStateException If the accessor is called on a non-root match instance.
+     */
+    public List<OccurrenceMatchingResult> getMultiple() {
+        if (!isAtRoot) {
+            throw new IllegalStateException("Only the root match could contain multiple submatches");
+        }
+        verifyPropertyPresence(MULTIPLE);
+
+        //noinspection unchecked
+        List<Map<String, Object>> multiple = (List<Map<String, Object>>) getCommandResult().get(MULTIPLE);
+        return multiple.stream()
+                .map((m) -> new OccurrenceMatchingResult(m, false))
+                .collect(Collectors.toList());
+    }
 }