Extract MammothOptionals.flatMap

2 files changed, 23 insertions, 7 deletions

diff --git a/src/main/java/org/zwobble/mammoth/docx/BodyXmlReader.java b/src/main/java/org/zwobble/mammoth/docx/BodyXmlReader.java
index 7a235a2..334f925 100644
--- a/src/main/java/org/zwobble/mammoth/docx/BodyXmlReader.java
+++ b/src/main/java/org/zwobble/mammoth/docx/BodyXmlReader.java
@@ -2,6 +2,7 @@ package org.zwobble.mammoth.docx;
 
 import com.google.common.collect.ImmutableList;
 import org.zwobble.mammoth.documents.*;
+import org.zwobble.mammoth.util.MammothOptionals;
 import org.zwobble.mammoth.xml.XmlElement;
 import org.zwobble.mammoth.xml.XmlElementLike;
 import org.zwobble.mammoth.xml.XmlNode;
@@ -63,13 +64,10 @@ public class BodyXmlReader {
 
     private Optional<NumberingLevel> readNumbering(XmlElementLike properties) {
         XmlElementLike numberingProperties = properties.findChildOrEmpty("w:numPr");
-        Optional<String> numId = readVal(numberingProperties, "w:numId");
-        Optional<String> levelIndex = readVal(numberingProperties, "w:ilvl");
-        if (numId.isPresent() && levelIndex.isPresent()) {
-            return numbering.findLevel(numId.get(), levelIndex.get());
-        } else {
-            return Optional.empty();
-        }
+        return MammothOptionals.flatMap(
+            readVal(numberingProperties, "w:numId"),
+            readVal(numberingProperties, "w:ilvl"),
+            numbering::findLevel);
     }
 
     private Optional<String> readVal(XmlElementLike element, String name) {
diff --git a/src/main/java/org/zwobble/mammoth/util/MammothOptionals.java b/src/main/java/org/zwobble/mammoth/util/MammothOptionals.java
new file mode 100644
index 0000000..e0e4876
--- /dev/null
+++ b/src/main/java/org/zwobble/mammoth/util/MammothOptionals.java
@@ -0,0 +1,18 @@
+package org.zwobble.mammoth.util;
+
+import java.util.Optional;
+import java.util.function.BiFunction;
+
+public class MammothOptionals {
+    public static <T1, T2, R> Optional<R> flatMap(
+        Optional<T1> first,
+        Optional<T2> second,
+        BiFunction<T1, T2, Optional<R>> function)
+    {
+        if (first.isPresent() && second.isPresent()) {
+            return function.apply(first.get(), second.get());
+        } else {
+            return Optional.empty();
+        }
+    }
+}