vvysotskyi commented on a change in pull request #2016: DRILL-7631: Updates to
the Json Structure Parser
URL: https://github.com/apache/drill/pull/2016#discussion_r390423322
##########
File path:
exec/java-exec/src/main/java/org/apache/drill/exec/store/easy/json/parser/ObjectListener.java
##########
@@ -52,80 +52,64 @@
*/
public interface ObjectListener {
+ public enum FieldType {
+
+ /**
+ * The field is unprojected, ignore its content. No value listener
+ * is created.
+ */
+ IGNORE,
+
+ /**
+ * Parse the JSON object according to its type.
+ */
+ TYPED,
+
+ /**
+ * The field is to be treated as "all-text". Used when the parser-level
+ * setting for {@code allTextMode} is {@code false}; allows per-field
+ * overrides to, perhaps, ride over inconsistent scalar types for a
+ * single field. The listener will receive only strings.
+ */
+ TEXT,
+
+ /**
+ * Parse the value, and all its children, as JSON.
+ * That is, converts the parsed JSON back into a
+ * JSON string. The listener will receive only strings.
+ */
+ JSON
+ }
+
/**
* Called at the start of a set of values for an object. That is, called
* when the structure parser accepts the <code>{</code> token.
*/
void onStart();
- /**
- * Called at the end of a set of values for an object. That is, called
- * when the structure parser accepts the <code>}</code> token.
- */
- void onEnd();
-
/**
* Called by the structure parser when it first sees a new field for
- * and object to determine if that field is to be projected (is needed
- * by the listener.) If not projected, the structure parser will not
+ * and object to determine how to parse the field.
+ * If not projected, the structure parser will not
* ask for a value listener and will insert a "dummy" parser that will
* free-wheel over any value of that field. As a result, unprojected
* fields can not cause type errors: they are invisible as long as
* they are syntactically valid.
+ * <p>
+ * The {@link FieldType#JSON} type says to parse the entire field, and
+ * its children, as a JSON string. The parser will ask for a value
+ * listener to accept the JSON text.
*
* @param key the object field name
- * @return {@code true} if this listener wants to provide a listener
- * for the field, {@code false} if the field should be ignored
- */
- boolean isProjected(String key);
-
- /**
- * A new field has appeared with a scalar (or {@code null}) value.
- * That is: {@code key: <scalar>}.
- *
- * @param key the field name
- * @param type the type as given by the JSON token for the value
- * @return a value listener for the scalar value
+ * @return how the field should be parsed
*/
- ValueListener addScalar(String key, JsonType type);
+ FieldType fieldType(String key);
- /**
- * A new field has appeared with a scalar, {@code null} or empty array
- * value. That is, one of:
- * <ul>
- * <li><code>key: [+ <scalar></code></li>
- * <li><code>key: [+ null</code></li>
- * <li><code>key: [+ ]</code></li>
- * </ul>
- * Where "[+" means one or more opening array elements.
- *
- * @param key the field name
- * @param arrayDims number of dimensions observed in the first appearance
- * of the array (more may appear later)
- * @param type the observed type of the first element of the array, or
- * {@link JsonType.NULL} if {@code null} was see, or
- * {@link JsonType.EMPTY} if an empty array was seen
- * @return a listener for the field itself which is prepared to
- * return an array listener
- */
- ValueListener addArray(String key, int arrayDims, JsonType type);
+ ValueListener addField(String key, ValueDef valueDef);
Review comment:
Please add JavaDoc.
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