add file drop handler

You can define a folder and ingest files dropped into it.

pdb-ui/src/main/java/org/lucares/pdbui/CsvReaderSettings.java

@@ -2,6 +2,7 @@ package org.lucares.pdbui;
 
 import java.nio.charset.StandardCharsets;
 import java.util.ArrayList;
+import java.util.Collection;
 import java.util.EnumSet;
 import java.util.HashMap;
 import java.util.Iterator;
@@ -12,8 +13,13 @@ import java.util.function.Function;
 import org.lucares.pdbui.domain.TagMatcher;
 import org.lucares.utils.Preconditions;
 
+import com.fasterxml.jackson.core.JsonProcessingException;
+import com.fasterxml.jackson.databind.ObjectMapper;
+
 public final class CsvReaderSettings {
 
+    private final static ObjectMapper OBJECT_MAPPER = new ObjectMapper();
+
     public static String stripPrefixDefault(final String value) {
         if (value.startsWith("Default")) {
             return value.replaceFirst("Default", "");
@@ -169,7 +175,7 @@ public final class CsvReaderSettings {
 
     private String comment = "#";
 
-    private List<TagMatcher> firstLineMatcher = new ArrayList<>();
+    private final List<TagMatcher> firstLineMatcher = new ArrayList<>();
 
     public CsvReaderSettings() {
         this("@timestamp", "duration", ",", new ColumnDefinitions());
@@ -244,7 +250,7 @@ public final class CsvReaderSettings {
     }
 
     public void putAdditionalTag(final Map<String, String> additionalTags) {
-        additionalTags.putAll(additionalTags);
+        this.additionalTags.putAll(additionalTags);
     }
 
     public Map<String, String> getAdditionalTags() {
@@ -267,8 +273,22 @@ public final class CsvReaderSettings {
         return firstLineMatcher;
     }
 
-    public void setFirstLineMatcher(final List<TagMatcher> firstLineMatcher) {
-        this.firstLineMatcher = firstLineMatcher;
+    public void setFirstLineMatcher(final Collection<TagMatcher> firstLineMatchers) {
+        this.firstLineMatcher.clear();
+        this.firstLineMatcher.addAll(firstLineMatchers);
+    }
+
+    public void addFirstLineMatcher(final TagMatcher tagMatcher) {
+        this.firstLineMatcher.add(tagMatcher);
+    }
+
+    public CsvReaderSettings copy() {
+        try {
+            final String json = OBJECT_MAPPER.writeValueAsString(this);
+            return OBJECT_MAPPER.readValue(json, CsvReaderSettings.class);
+        } catch (final JsonProcessingException e) {
+            throw new IllegalStateException(e);
+        }
     }
 
     @Override