From 7c53fb46d8c78d9a4c35964a792ff9f17d35eb85 Mon Sep 17 00:00:00 2001
From: John Bauer <horatio@gmail.com>
Date: Thu, 12 Oct 2023 21:38:08 -0700
Subject: [PATCH] Move the EmptyIndex into the CoreLabel, as that may be the
 easiest way to pass it from Python to Java in the Semgrex interface

---
 src/edu/stanford/nlp/ling/CoreLabel.java   | 30 ++++++++++++++++++++++
 src/edu/stanford/nlp/ling/IndexedWord.java | 12 ++++-----
 2 files changed, 36 insertions(+), 6 deletions(-)

diff --git a/src/edu/stanford/nlp/ling/CoreLabel.java b/src/edu/stanford/nlp/ling/CoreLabel.java
index bbad7791fa..4710c027ef 100644
--- a/src/edu/stanford/nlp/ling/CoreLabel.java
+++ b/src/edu/stanford/nlp/ling/CoreLabel.java
@@ -606,6 +606,36 @@ public void setIndex(int index) {
     set(CoreAnnotations.IndexAnnotation.class, index);
   }
 
+  /**
+   * Similar to a copy node in IndexedWord, but not exactly,
+   * as the word can have its own attributes.
+   * Fairly common in enhanced graphs in UD
+   */
+  public int getEmptyIndex() {
+    Integer index = get(CoreAnnotations.EmptyIndexAnnotation.class);
+    if (index == null) {
+      return 0;
+    }
+    return index;
+  }
+
+  /**
+   * Similar to a copy node in IndexedWord, but not exactly,
+   * as the word can have its own attributes.
+   * Fairly common in enhanced graphs in UD
+   */
+  public void setEmptyIndex(int empty) {
+    set(CoreAnnotations.EmptyIndexAnnotation.class, empty);
+  }
+
+  /**
+   * Keeping track of this can save us a little effort when serializing CoreLabels
+   */
+  public boolean hasEmptyIndex() {
+    Integer index = get(CoreAnnotations.EmptyIndexAnnotation.class);
+    return index != null;
+  }
+
   /**
    * {@inheritDoc}
    */
diff --git a/src/edu/stanford/nlp/ling/IndexedWord.java b/src/edu/stanford/nlp/ling/IndexedWord.java
index 6f2fffa6b8..f71a22f4a8 100644
--- a/src/edu/stanford/nlp/ling/IndexedWord.java
+++ b/src/edu/stanford/nlp/ling/IndexedWord.java
@@ -347,15 +347,15 @@ public void setEndPosition(int endPos) {
   }
 
   public void setEmptyIndex(int empty) {
-    label.set(CoreAnnotations.EmptyIndexAnnotation.class, empty);
+    label.setEmptyIndex(empty);
   }
 
   public int getEmptyIndex() {
-    Integer index = label.get(CoreAnnotations.EmptyIndexAnnotation.class);
-    if (index == null) {
-      return 0;
-    }
-    return index;
+    return label.getEmptyIndex();
+  }
+
+  public boolean hasEmptyIndex() {
+    return label.hasEmptyIndex();
   }
 
   public int copyCount() {