Add lazyMap implementation

2 files changed, 27 insertions, 2 deletions

diff --git a/src/main/java/org/zwobble/mammoth/DocumentConverter.java b/src/main/java/org/zwobble/mammoth/DocumentConverter.java
index faa45ef..d2d2cc9 100644
--- a/src/main/java/org/zwobble/mammoth/DocumentConverter.java
+++ b/src/main/java/org/zwobble/mammoth/DocumentConverter.java
@@ -1,6 +1,5 @@
 package org.zwobble.mammoth;
 
-import com.google.common.collect.Iterables;
 import org.zwobble.mammoth.internal.DocumentToHtml;
 import org.zwobble.mammoth.internal.DocumentToHtmlOptions;
 import org.zwobble.mammoth.internal.documents.DocumentElement;
@@ -24,6 +23,7 @@ import java.util.function.Function;
 import java.util.zip.ZipFile;
 
 import static org.zwobble.mammoth.internal.docx.DocumentReader.readDocument;
+import static org.zwobble.mammoth.internal.util.MammothIterables.lazyMap;
 import static org.zwobble.mammoth.internal.util.MammothLists.list;
 
 public class DocumentConverter {
@@ -138,7 +138,7 @@ public class DocumentConverter {
     }
 
     private static String extractRawText(List<DocumentElement> nodes) {
-        return String.join("", Iterables.transform(nodes, node -> extractRawText(node)));
+        return String.join("", lazyMap(nodes, node -> extractRawText(node)));
     }
 
     private static String extractRawText(DocumentElement node) {
diff --git a/src/main/java/org/zwobble/mammoth/internal/util/MammothIterables.java b/src/main/java/org/zwobble/mammoth/internal/util/MammothIterables.java
index 4335dc1..0280ac9 100644
--- a/src/main/java/org/zwobble/mammoth/internal/util/MammothIterables.java
+++ b/src/main/java/org/zwobble/mammoth/internal/util/MammothIterables.java
@@ -2,7 +2,9 @@ package org.zwobble.mammoth.internal.util;
 
 import com.google.common.collect.Iterables;
 
+import java.util.Iterator;
 import java.util.Optional;
+import java.util.function.Function;
 import java.util.function.Predicate;
 
 public class MammothIterables {
@@ -18,4 +20,27 @@ public class MammothIterables {
         }
         return Optional.empty();
     }
+
+    public static <T, R> Iterable<R> lazyMap(Iterable<T> iterable, Function<T, R> function) {
+        return new Iterable<R>() {
+            @Override
+            public Iterator<R> iterator() {
+                return map(iterable.iterator(), function);
+            }
+        };
+    }
+
+    private static <T, R> Iterator<R> map(Iterator<T> iterator, Function<T, R> function) {
+        return new Iterator<R>() {
+            @Override
+            public boolean hasNext() {
+                return iterator.hasNext();
+            }
+
+            @Override
+            public R next() {
+                return function.apply(iterator.next());
+            }
+        };
+    }
 }