expose simplified field methods for custom scripts

also, add respective iter methods to the script values to be used in custom scripts

src/main/java/org/elasticsearch/index/fielddata/ScriptDocValues.java

@@ -98,6 +98,18 @@ public abstract class ScriptDocValues {
             return !values.hasValue(docId);
         }
 
+        public BytesValues getInternalValues() {
+            return this.values;
+        }
+
+        public Iter getBytesIter() {
+            return values.getIter(docId);
+        }
+
+        public BytesRef getBytesValue() {
+            return values.getValue(docId);
+        }
+
         public String getValue() {
             final BytesRef value = values.getValue(docId);
             if (value != null) {
@@ -137,11 +149,19 @@ public abstract class ScriptDocValues {
             this.list = new SlicedLongList(values.isMultiValued() ? 10 : 1);
         }
 
+        public LongValues getInternalValues() {
+            return this.values;
+        }
+
         @Override
         public boolean isEmpty() {
             return !values.hasValue(docId);
         }
 
+        public LongValues.Iter getIter() {
+            return values.getIter(docId);
+        }
+
         public long getValue() {
             return values.getValue(docId);
         }
@@ -178,11 +198,19 @@ public abstract class ScriptDocValues {
 
         }
 
+        public DoubleValues getInternalValues() {
+            return this.values;
+        }
+
         @Override
         public boolean isEmpty() {
             return !values.hasValue(docId);
         }
 
+        public DoubleValues.Iter getIter() {
+            return values.getIter(docId);
+        }
+
         public double getValue() {
             return values.getValue(docId);
         }

src/main/java/org/elasticsearch/script/AbstractSearchScript.java

@@ -21,6 +21,7 @@ package org.elasticsearch.script;
 
 import org.apache.lucene.index.AtomicReaderContext;
 import org.apache.lucene.search.Scorer;
+import org.elasticsearch.index.fielddata.ScriptDocValues;
 import org.elasticsearch.search.lookup.DocLookup;
 import org.elasticsearch.search.lookup.FieldsLookup;
 import org.elasticsearch.search.lookup.SearchLookup;
@@ -59,6 +60,27 @@ public abstract class AbstractSearchScript extends AbstractExecutableScript impl
         return lookup.doc();
     }
 
+    /**
+     * Returns field data strings access for the provided field.
+     */
+    protected ScriptDocValues.Strings docFieldStrings(String field) {
+        return (ScriptDocValues.Strings) doc().get(field);
+    }
+
+    /**
+     * Returns field data double (floating point) access for the provided field.
+     */
+    protected ScriptDocValues.Doubles docFieldDoubles(String field) {
+        return (ScriptDocValues.Doubles) doc().get(field);
+    }
+
+    /**
+     * Returns field data long (integers) access for the provided field.
+     */
+    protected ScriptDocValues.Longs docFieldLongs(String field) {
+        return (ScriptDocValues.Longs) doc().get(field);
+    }
+
     /**
      * Allows to access the actual source (loaded and parsed).
      */