Github user markap14 commented on a diff in the pull request:
https://github.com/apache/nifi/pull/2570#discussion_r176438047
--- Diff:
nifi-commons/nifi-record-path/src/main/java/org/apache/nifi/record/path/functions/ToString.java
---
@@ -0,0 +1,95 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.nifi.record.path.functions;
+
+import org.apache.nifi.record.path.FieldValue;
+import org.apache.nifi.record.path.RecordPathEvaluationContext;
+import org.apache.nifi.record.path.StandardFieldValue;
+import org.apache.nifi.record.path.paths.RecordPathSegment;
+import org.apache.nifi.record.path.util.RecordPathUtils;
+import org.apache.nifi.serialization.record.util.DataTypeUtils;
+
+import java.nio.charset.Charset;
+import java.util.stream.Stream;
+
+public class ToString extends RecordPathSegment {
+
+ private final RecordPathSegment recordPath;
+ private final RecordPathSegment charsetSegment;
+
+ public ToString(final RecordPathSegment recordPath, final
RecordPathSegment charsetSegment, final boolean absolute) {
+ super("toString", null, absolute);
+ this.recordPath = recordPath;
+ this.charsetSegment = charsetSegment;
+ }
+
+ @Override
+ public Stream<FieldValue> evaluate(RecordPathEvaluationContext
context) {
+ final Stream<FieldValue> fieldValues =
recordPath.evaluate(context);
+ return fieldValues.filter(fv -> fv.getValue() != null)
+ .map(fv -> {
+ final Charset charset =
getCharset(this.charsetSegment, context);
+ Object value = fv.getValue();
+ final String stringValue;
+
+ if (value instanceof Object[]) {
+ Object[] o = (Object[]) value;
+ if (o.length > 0) {
+
+ byte[] dest = new byte[o.length];
+ for (int i = 0; i < o.length; i++) {
+ dest[i] = (byte) o[i];
+ }
+ stringValue = new String(dest, charset);
+ } else {
+ stringValue = ""; // Empty array = empty string
+ }
+ } else if (!(fv.getValue() instanceof byte[])) {
+ return fv;
--- End diff --
This probably warrants throwing an Exception. It seems wrong to me to have
the user explicitly indicating that they want a conversion to a String and then
return something different, like an Integer.
---
