Add utilities to check the min & max index of a SemanticGraph

Author: AngledLuffa

src/edu/stanford/nlp/semgraph/SemanticGraphUtils.java

@@ -1287,4 +1287,24 @@ public static boolean isTree(SemanticGraph sg) {
 
     return visitedNodes.size() == sg.size();
   }
+
+  public static int maxIndex(SemanticGraph sg) {
+    int index = Integer.MIN_VALUE;
+    for (IndexedWord node : sg.vertexSet()) {
+      if (node.index() > index) {
+        index = node.index();
+      }
+    }
+    return index;
+  }
+
+  public static int minIndex(SemanticGraph sg) {
+    int index = Integer.MAX_VALUE;
+    for (IndexedWord node : sg.vertexSet()) {
+      if (node.index() < index) {
+        index = node.index();
+      }
+    }
+    return index;
+  }
 }

test/src/edu/stanford/nlp/semgraph/SemanticGraphUtilsTest.java

@@ -35,4 +35,34 @@ public void testCreateSemgrexPattern(){
     assertEquals("{word: ate; tag: null; ner: null}=ate  >subj=E1 {word: bill; tag: null; ner: null}=Bill", pat.trim());
   }
 
+  @Test
+  public void testMaxIndex() {
+    SemanticGraph sg = SemanticGraph.valueOf("[has-2 nsubj> Jennifer-1 obj> [antennae-4 dep> blue-3]]");
+    assertEquals(4, SemanticGraphUtils.maxIndex(sg));
+
+    // with a weird index
+    sg = SemanticGraph.valueOf("[has-2 nsubj> Jennifer-1 obj> [antennae-5 dep> blue-3]]");
+    assertEquals(5, SemanticGraphUtils.maxIndex(sg));
+
+    sg = SemanticGraph.valueOf("[has-1 nsubj> Jennifer-0 obj> [antennae-3 dep> blue-2]]");
+    assertEquals(3, SemanticGraphUtils.maxIndex(sg));
+
+    sg = SemanticGraph.valueOf("[foo-1]");
+    assertEquals(1, SemanticGraphUtils.maxIndex(sg));
+  }
+
+  @Test
+  public void testMinIndex() {
+    SemanticGraph sg = SemanticGraph.valueOf("[has-2 nsubj> Jennifer-1 obj> [antennae-4 dep> blue-3]]");
+    assertEquals(1, SemanticGraphUtils.minIndex(sg));
+
+    sg = SemanticGraph.valueOf("[has-2 nsubj> Jennifer-1 obj> [antennae-5 dep> blue-3]]");
+    assertEquals(1, SemanticGraphUtils.minIndex(sg));
+
+    sg = SemanticGraph.valueOf("[has-1 nsubj> Jennifer-0 obj> [antennae-3 dep> blue-2]]");
+    assertEquals(0, SemanticGraphUtils.minIndex(sg));
+
+    sg = SemanticGraph.valueOf("[foo-1]");
+    assertEquals(1, SemanticGraphUtils.minIndex(sg));
+  }
 }