1 files changed, 58 insertions, 0 deletions
diff --git a/streamingvisitors/src/vespa/vsm/common/fieldmodifier.h b/streamingvisitors/src/vespa/vsm/common/fieldmodifier.h
new file mode 100644
index 00000000000..60e480fa237
--- /dev/null
+++ b/streamingvisitors/src/vespa/vsm/common/fieldmodifier.h
@@ -0,0 +1,58 @@
+// Copyright Yahoo. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+#pragma once
+
+#include <vespa/document/fieldvalue/fieldvalue.h>
+#include <vespa/vsm/common/document.h>
+
+namespace vsm {
+
+/**
+ * Interface for classes that want to modify a field value.
+ **/
+class FieldModifier
+{
+public:
+    typedef std::unique_ptr<FieldModifier> UP;
+
+    /**
+     * Modifies the given field value and returns a new one.
+     **/
+    virtual document::FieldValue::UP modify(const document::FieldValue & fv) = 0;
+
+    /**
+     * Modifies the given field value and returns a new one.
+     * Use the given field path to iterate the field value.
+     **/
+    virtual document::FieldValue::UP modify(const document::FieldValue & fv,
+                                            const document::FieldPath & path) = 0;
+
+    virtual ~FieldModifier() { }
+};
+
+typedef vespalib::hash_map<FieldIdT, FieldModifier::UP> FieldModifierMapT;
+
+/**
+ * This class wraps a map from field id to field modifier.
+ **/
+class FieldModifierMap
+{
+private:
+    FieldModifierMapT _map;
+
+public:
+    FieldModifierMap();
+    ~FieldModifierMap();
+    FieldModifierMapT & map() { return _map; }
+    const FieldModifierMapT & map() const { return _map; }
+
+    /**
+     * Returns the modifier associated with the given field id or NULL if not found.
+     *
+     * @param fId the field id to look up.
+     * @return the field modifier or NULL if not found.
+     **/
+    FieldModifier * getModifier(FieldIdT fId) const;
+};
+
+}
+