From abca2efe3818d9aab3b8a8beac4c53c30add6b92 Mon Sep 17 00:00:00 2001
From: Jens Wille <jens.wille@hbz-nrw.de>
Date: Tue, 11 Jan 2022 16:21:11 +0100
Subject: [PATCH] Add `join_field()` Fix function. (#100)

---
 .../org/metafacture/metafix/FixMethod.java    |  8 +++++++
 .../metafix/MetafixMethodTest.java            | 21 +++++++++++++++++++
 2 files changed, 29 insertions(+)

diff --git a/metafix/src/main/java/org/metafacture/metafix/FixMethod.java b/metafix/src/main/java/org/metafacture/metafix/FixMethod.java
index 4a9a7f43..2d3504c1 100644
--- a/metafix/src/main/java/org/metafacture/metafix/FixMethod.java
+++ b/metafix/src/main/java/org/metafacture/metafix/FixMethod.java
@@ -293,6 +293,14 @@ public void apply(final Metafix metafix, final Record record, final List<String>
             record.transformFields(params, s -> String.valueOf(s.indexOf(search))); // TODO: multiple
         }
     },
+    join_field {
+        public void apply(final Metafix metafix, final Record record, final List<String> params, final Map<String, String> options) {
+            record.transformField(params.get(0), v -> {
+                final String joinChar = params.size() > 1 ? params.get(1) : "";
+                return v.isArray() ? new Value(v.asArray().stream().map(Value::toString).collect(Collectors.joining(joinChar))) : null;
+            });
+        }
+    },
     lookup {
         public void apply(final Metafix metafix, final Record record, final List<String> params, final Map<String, String> options) {
             final Map<String, String> map;
diff --git a/metafix/src/test/java/org/metafacture/metafix/MetafixMethodTest.java b/metafix/src/test/java/org/metafacture/metafix/MetafixMethodTest.java
index 75d0840a..d4d1e6b9 100644
--- a/metafix/src/test/java/org/metafacture/metafix/MetafixMethodTest.java
+++ b/metafix/src/test/java/org/metafacture/metafix/MetafixMethodTest.java
@@ -625,6 +625,27 @@ public void shouldGetIndexOfSubstring() {
         );
     }
 
+    @Test
+    public void shouldJoinArrayField() {
+        MetafixTestHelpers.assertFix(streamReceiver, Arrays.asList(
+                "join_field(numbers, '/')"
+            ),
+            i -> {
+                i.startRecord("1");
+                i.literal("numbers", "6");
+                i.literal("numbers", "42");
+                i.literal("numbers", "41");
+                i.literal("numbers", "6");
+                i.endRecord();
+            },
+            o -> {
+                o.get().startRecord("1");
+                o.get().literal("numbers", "6/42/41/6");
+                o.get().endRecord();
+            }
+        );
+    }
+
     @Test
     public void shouldPrependValue() {
         MetafixTestHelpers.assertFix(streamReceiver, Arrays.asList(