create array mapper for io strategies

src/main/java/de/marhali/easyi18n/io/ArrayMapper.java

@@ -0,0 +1,61 @@
+package de.marhali.easyi18n.io;
+
+import de.marhali.easyi18n.util.StringUtil;
+
+import org.apache.commons.lang.StringEscapeUtils;
+
+import java.text.MessageFormat;
+import java.util.Iterator;
+import java.util.function.Consumer;
+import java.util.function.Function;
+import java.util.regex.Pattern;
+
+/**
+ * Simple array support for translation values.
+ * Some i18n systems allows the user to define array values for some translations.
+ * We support array values by wrapping them into: '!arr[valueA;valueB]'.
+ *
+ * @author marhali
+ */
+public abstract class ArrayMapper {
+    static final String PREFIX = "!arr[";
+    static final String SUFFIX = "]";
+    static final char DELIMITER = ';';
+
+    static final String SPLITERATOR_REGEX =
+            MessageFormat.format("(?<!\\\\){0}", Pattern.quote(String.valueOf(DELIMITER)));
+
+    protected static <T> String read(Iterator<T> elements, Function<T, String> stringFactory) {
+        StringBuilder builder = new StringBuilder(PREFIX);
+
+        int i = 0;
+        while(elements.hasNext()) {
+            if(i > 0) {
+                builder.append(DELIMITER);
+            }
+
+            String value = stringFactory.apply(elements.next());
+
+            builder.append(StringUtil.escapeControls(
+                    value.replace(String.valueOf(DELIMITER), "\\" + DELIMITER), true));
+
+            i++;
+        }
+
+        builder.append(SUFFIX);
+        return builder.toString();
+    }
+
+    protected static void write(String concat, Consumer<String> writeElement) {
+        concat = concat.substring(PREFIX.length(), concat.length() - SUFFIX.length());
+
+        for(String element : concat.split(SPLITERATOR_REGEX)) {
+            element = element.replace("\\" + DELIMITER, String.valueOf(DELIMITER));
+            writeElement.accept(StringEscapeUtils.unescapeJava(element));
+        }
+    }
+
+    public static boolean isArray(String concat) {
+        return concat != null && concat.startsWith(PREFIX) && concat.endsWith(SUFFIX);
+    }
+}