Ensure marc:leader to be emitted first (#548)

Author: dr0i

metafacture-biblio/src/main/java/org/metafacture/biblio/marc21/MarcXmlEncoder.java

@@ -252,6 +252,7 @@ private static class Encoder extends DefaultStreamPipe<ObjectReceiver<String>> {
         private int indentationLevel;
         private boolean formatted = PRETTY_PRINTED;
         private int recordAttributeOffset;
+        private int recordLeaderOffset;
 
         private Encoder() {
         }
@@ -294,7 +295,7 @@ public void startRecord(final String identifier) {
             writeTag(Tag.record::open);
             recordAttributeOffset = builder.length() - 1;
             prettyPrintNewLine();
-
+            recordLeaderOffset = builder.length();
             incrementIndentationLevel();
         }
 
@@ -353,7 +354,7 @@ else if (!appendLeader(name, value)) {
                     if (value != null) {
                         writeEscaped(value.trim());
                     }
-                    writeTag(Tag.controlfield::close);
+                    writeTag(Tag.controlfield::close, false);
                     prettyPrintNewLine();
                 }
             }
@@ -408,9 +409,20 @@ private void writeFooter() {
          * @param str the unescaped sequence to be written
          */
         private void writeRaw(final String str) {
+
             builder.append(str);
         }
 
+        /**
+         * Writes the unescaped sequence to the leader position.
+         *
+         * @param str the unescaped sequence to be written to the leader position
+         */
+        private void writeRawLeader(final String str) {
+            builder.insert(recordLeaderOffset, str);
+            recordLeaderOffset = recordLeaderOffset + str.length();
+        }
+
         private boolean appendLeader(final String name, final String value) {
             if (name.equals(Marc21EventNames.LEADER_ENTITY)) {
                 leaderBuilder.append(value);
@@ -432,11 +444,11 @@ private void writeEscaped(final String str) {
 
         private void writeLeader() {
             final String leader = leaderBuilder.toString();
-            if (!leader.isEmpty()) {
+            if (leaderBuilder.length() > 0) {
                 prettyPrintIndentation();
-                writeTag(Tag.leader::open);
-                writeRaw(leader);
-                writeTag(Tag.leader::close);
+                writeTagLeader(Tag.leader::open);
+                writeRawLeader(leader);
+                writeTagLeader(Tag.leader::close);
                 prettyPrintNewLine();
             }
         }
@@ -447,6 +459,11 @@ private void writeTag(final Function<Object[], String> function, final Object...
             writeRaw(function.apply(allArgs));
         }
 
+        private void writeTagLeader(final Function<Object[], String> function) {
+            writeRawLeader(function.apply(namespacePrefix));
+        }
+
+
         private void prettyPrintIndentation() {
             if (formatted) {
                 final String prefix = String.join("", Collections.nCopies(indentationLevel, INDENT));

metafacture-biblio/src/test/java/org/metafacture/biblio/marc21/MarcXmlEncoderTest.java

@@ -25,6 +25,7 @@
 import org.junit.Test;
 
 import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotEquals;
 import static org.junit.Assert.assertTrue;
 
 /**
@@ -249,12 +250,26 @@ private void issue336_createRecordWithTopLevelLeader(final MarcXmlEncoder encode
         encoder.endRecord();
         encoder.closeStream();
         String expected = XML_DECLARATION + XML_ROOT_OPEN
-            + "<marc:record><marc:controlfield tag=\"001\">8u3287432</marc:controlfield>" +
-            "<marc:leader>" + expectedLeader + "</marc:leader></marc:record>" + XML_MARC_COLLECTION_END_TAG;
+            + "<marc:record><marc:leader>" + expectedLeader + "</marc:leader>" +
+            "<marc:controlfield tag=\"001\">8u3287432</marc:controlfield></marc:record>" + XML_MARC_COLLECTION_END_TAG;
         String actual = resultCollector.toString();
         assertEquals(expected, actual);
     }
 
+    @Test
+    public void issue548_failWhenLeaderIsNotFirst() {
+        encoder.startRecord("1");
+        encoder.literal("001", "8u3287432");
+        encoder.literal(Marc21EventNames.LEADER_ENTITY, "00000naa a2200000uc 4500");
+        encoder.endRecord();
+        encoder.closeStream();
+        String expected = XML_DECLARATION + XML_ROOT_OPEN
+            + "<marc:record><marc:controlfield tag=\"001\">8u3287432</marc:controlfield>" +
+            "<marc:leader>00000naa a2200000uc 4500</marc:leader></marc:record>" + XML_MARC_COLLECTION_END_TAG;
+        String actual = resultCollector.toString();
+        assertNotEquals(expected, actual);
+    }
+
     @Test
     public void issue527_shouldEmitLeaderAlwaysAsWholeString() {
         createRecordWithLeader("1", "a", "o", "a", " ", "a", "z", "u", " ");