1 files changed, 18 insertions, 4 deletions
diff --git a/src/main/java/org/zwobble/mammoth/Mammoth.java b/src/main/java/org/zwobble/mammoth/Mammoth.java
index d466bed..5830c6a 100644
--- a/src/main/java/org/zwobble/mammoth/Mammoth.java
+++ b/src/main/java/org/zwobble/mammoth/Mammoth.java
@@ -8,14 +8,13 @@ import org.zwobble.mammoth.xml.XmlElement;
 
 import java.io.File;
 import java.io.IOException;
+import java.util.Optional;
 import java.util.zip.ZipFile;
 
 public class Mammoth {
     public static Result<String> convertToHtml(File file) {
         try (DocxFile zipFile = new ZippedDocxFile(new ZipFile(file))) {
-            XmlElement documentXml = OfficeXml.parseXml(zipFile.getInputStream("word/document.xml"));
-
-            Styles styles = Styles.EMPTY;
+            Styles styles = readStyles(zipFile);
             Numbering numbering = Numbering.EMPTY;
             Relationships relationships = Relationships.EMPTY;
             ContentTypes contentTypes = ContentTypes.DEFAULT;
@@ -32,7 +31,7 @@ public class Mammoth {
                 fileReader), notes);
             // TODO: prefix
             String idPrefix = "document";
-            return reader.readElement(documentXml)
+            return reader.readElement(parseOfficeXml(zipFile, "word/document.xml"))
                 .map(nodes -> DocumentConverter.convertToHtml(idPrefix, nodes))
                 .map(Html::stripEmpty)
                 .map(Html::collapse)
@@ -41,4 +40,19 @@ public class Mammoth {
             throw new UnsupportedOperationException("Should return a result of failure");   
         }
     }
+
+    private static Styles readStyles(DocxFile file) throws IOException {
+        return tryParseOfficeXml(file, "word/styles.xml")
+            .map(StylesXml::readStylesXmlElement)
+            .orElse(Styles.EMPTY);
+    }
+
+    private static Optional<XmlElement> tryParseOfficeXml(DocxFile zipFile, String name) throws IOException {
+        return zipFile.tryGetInputStream(name).map(OfficeXml::parseXml);
+    }
+
+    private static XmlElement parseOfficeXml(DocxFile zipFile, String name) throws IOException {
+        return tryParseOfficeXml(zipFile, name)
+            .orElseThrow(() -> new IOException("Missing entry in file: " + name));
+    }
 }