add basic expansion model

Author: jenschude

commercetools/commercetools-sdk-java-api/src/main/java/com/commercetools/api/predicates/expansion/ObjectExpansionDsl.java

@@ -0,0 +1,26 @@
+
+package com.commercetools.api.predicates.expansion;
+
+import java.util.Collections;
+import java.util.List;
+
+public class ObjectExpansionDsl implements ExpansionDsl {
+    private final List<String> path;
+
+    private ObjectExpansionDsl(final List<String> path) {
+        this.path = path;
+    }
+
+    @Override
+    public List<String> getPath() {
+        return path;
+    }
+
+    public static ObjectExpansionDsl of() {
+        return new ObjectExpansionDsl(Collections.emptyList());
+    }
+
+    public static ObjectExpansionDsl of(final List<String> path) {
+        return new ObjectExpansionDsl(path);
+    }
+}