#355 document, abstract base, traits and example domain

abstract-document/src/main/java/com/iluwatar/abstractdocument/Document.java

@@ -0,0 +1,34 @@
+package com.iluwatar.abstractdocument;
+
+import java.util.Map;
+import java.util.function.Function;
+import java.util.stream.Stream;
+
+public interface Document {
+
+	/**
+	 * Puts the value related to the key
+	 * 
+	 * @param key
+	 * @param value
+	 * @return Void
+	 */
+	Void put(String key, Object value);
+
+	/**
+	 * Gets the value for the key
+	 * 
+	 * @param key
+	 * @return value or null
+	 */
+	Object get(String key);
+
+	/**
+	 * Gets the stream of child documents
+	 * 
+	 * @param key
+	 * @param constructor
+	 * @return child documents
+	 */
+	<T> Stream<T> children(String key, Function<Map<String, Object>, T> constructor);
+}