Expose Section's sectnum property

Update changelog

CHANGELOG.adoc

@@ -22,6 +22,7 @@ Improvement::
 * Upgrade to JRuby 9.3.8.0 (#1116)
 * Upgrade to tilt 2.0.11 (#1109)
 * Upgrade to asciimath 2.0.4 (#1109)
+* Expose `sectnum` property in Section interface (#1121)
 
 Bug Fixes::
 

asciidoctorj-api/src/main/java/org/asciidoctor/ast/Section.java

@@ -74,4 +74,24 @@ public interface Section extends StructuralNode {
      */
     boolean isNumbered();
 
+
+    /**
+     * Get the section number for the current Section.
+     * <p>
+     * The section number is a dot-separated String that uniquely describes the position of this
+     * Section in the document. Each entry represents a level of nesting. The value of each entry is
+     * the 1-based outline number of the Section amongst its numbered sibling Sections.
+     */
+    String getSectnum();
+
+    /**
+     * Get the section number for the current Section.
+     * <p>
+     * The section number is a dot-separated String that uniquely describes the position of this
+     * Section in the document. Each entry represents a level of nesting. The value of each entry is
+     * the 1-based outline number of the Section amongst its numbered sibling Sections.
+     *
+     * @param delimiter the delimiter to separate the number for each level
+     */
+    String getSectnum(String delimiter);
 }

asciidoctorj-core/src/main/java/org/asciidoctor/jruby/ast/impl/SectionImpl.java

@@ -70,4 +70,14 @@ public boolean isNumbered() {
         return getBoolean("numbered");
     }
 
+    @Override
+    public String getSectnum() {
+        return getString("sectnum");
+    }
+
+    @Override
+    public String getSectnum(String delimiter) {
+        return getString("sectnum", new Object[]{delimiter});
+    }
+
 }

asciidoctorj-core/src/test/java/org/asciidoctor/jruby/ast/impl/SectionImplTest.java

@@ -0,0 +1,100 @@
+package org.asciidoctor.jruby.ast.impl;
+
+import org.asciidoctor.Asciidoctor;
+import org.asciidoctor.Attributes;
+import org.asciidoctor.Options;
+import org.asciidoctor.ast.Document;
+import org.asciidoctor.ast.Section;
+import org.junit.Test;
+
+import java.util.Collections;
+
+import static java.lang.Boolean.FALSE;
+import static java.lang.Boolean.TRUE;
+import static org.hamcrest.CoreMatchers.is;
+import static org.hamcrest.MatcherAssert.assertThat;
+
+public class SectionImplTest {
+
+    private Asciidoctor asciidoctor = Asciidoctor.Factory.create();
+
+
+    @Test
+    public void should_return_valid_sectnum_when_sectionNumbers_are_enabled() {
+        final String source = sectionsSample();
+
+        Document document = loadDocument(source, true);
+
+        Section node1 = findSectionNode(document, 1);
+        assertThat(node1.getSectnum(), is("1."));
+        assertThat(node1.isNumbered(), is(TRUE));
+
+        Section node2 = findSectionNode(document, 2);
+        assertThat(node2.getSectnum(), is("1.1."));
+        assertThat(node2.isNumbered(), is(TRUE));
+    }
+
+    @Test
+    public void should_return_invalid_sectnum_when_sectionNumbers_are_not_enabled() {
+        final String source = sectionsSample();
+
+        Document document = loadDocument(source, false);
+
+        Section node1 = findSectionNode(document, 1);
+        assertThat(node1.getSectnum(), is("."));
+        assertThat(node1.isNumbered(), is(FALSE));
+
+        Section node2 = findSectionNode(document, 2);
+        assertThat(node2.getSectnum(), is(".."));
+        assertThat(node2.isNumbered(), is(FALSE));
+    }
+
+    @Test
+    public void should_return_sectnum_with_custom_delimiter_when_sectionNumbers_are_enabled() {
+        final String source = sectionsSample();
+
+        Document document = loadDocument(source, true);
+
+        Section node1 = findSectionNode(document, 1);
+        assertThat(node1.getSectnum("_"), is("1_"));
+
+        Section node2 = findSectionNode(document, 2);
+        assertThat(node2.getSectnum("*"), is("1*1*"));
+    }
+
+    @Test
+    public void should_return_sectnum_with_custom_delimiter_when_sectionNumbers_are_not_enabled() {
+        final String source = sectionsSample();
+
+        Document document = loadDocument(source, false);
+
+        Section node1 = findSectionNode(document, 1);
+        assertThat(node1.getSectnum("_"), is("_"));
+
+        Section node2 = findSectionNode(document, 2);
+        assertThat(node2.getSectnum("*"), is("**"));
+    }
+
+    private Document loadDocument(String source, boolean sectionNumbers) {
+        Attributes attributes = Attributes.builder().sectionNumbers(sectionNumbers).build();
+        Options options = Options.builder().attributes(attributes).build();
+        Document document = asciidoctor.load(source, options);
+        return document;
+    }
+
+    private Section findSectionNode(Document document, int level) {
+        return (Section) document.findBy(Collections.singletonMap("context", ":section"))
+                .stream()
+                .filter(n -> n.getLevel() == level)
+                .findFirst()
+                .get();
+    }
+
+    static String sectionsSample() {
+        return "= Document Title\n\n" +
+                "== Section A\n\n" +
+                "Section A paragraph.\n\n" +
+                "=== Section A Subsection\n\n" +
+                "Section A 'subsection' paragraph.\n\n";
+    }
+}