michaelmior commented on a change in pull request #1302: [CALCITE-3176] File
adapter for parsing JSON files
URL: https://github.com/apache/calcite/pull/1302#discussion_r305566941
##########
File path:
example/csv/src/main/java/org/apache/calcite/adapter/csv/JsonTable.java
##########
@@ -16,46 +16,91 @@
*/
package org.apache.calcite.adapter.csv;
-import org.apache.calcite.DataContext;
-import org.apache.calcite.linq4j.AbstractEnumerable;
-import org.apache.calcite.linq4j.Enumerable;
-import org.apache.calcite.linq4j.Enumerator;
import org.apache.calcite.rel.type.RelDataType;
import org.apache.calcite.rel.type.RelDataTypeFactory;
-import org.apache.calcite.schema.ScannableTable;
+import org.apache.calcite.schema.Statistic;
+import org.apache.calcite.schema.Statistics;
import org.apache.calcite.schema.impl.AbstractTable;
-import org.apache.calcite.sql.type.SqlTypeName;
+import org.apache.calcite.util.Pair;
import org.apache.calcite.util.Source;
+import com.fasterxml.jackson.core.JsonParser;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.exc.MismatchedInputException;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Map;
+
/**
* Table based on a JSON file.
*/
-public class JsonTable extends AbstractTable implements ScannableTable {
- private final Source source;
+public class JsonTable extends AbstractTable {
+ private final ObjectMapper objectMapper = new ObjectMapper();
+ protected final List<Object> list;
+
+ private LinkedHashMap<String, Object> jsonFieldMap = new LinkedHashMap<>(1);
- /** Creates a JsonTable. */
public JsonTable(Source source) {
- this.source = source;
- }
+ Object jsonObj = null;
+ try {
+ objectMapper.configure(JsonParser.Feature.ALLOW_UNQUOTED_FIELD_NAMES,
true)
+ .configure(JsonParser.Feature.ALLOW_SINGLE_QUOTES, true)
+ .configure(JsonParser.Feature.ALLOW_COMMENTS, true);
+ if (source.file().exists() && source.file().length() > 0) {
+ if ("file".equals(source.protocol())) {
+ //noinspection unchecked
+ jsonObj = objectMapper.readValue(source.file(), Object.class);
+ } else {
+ //noinspection unchecked
+ jsonObj = objectMapper.readValue(source.url(), Object.class);
+ }
+ }
+ } catch (MismatchedInputException e) {
+ if (!e.getMessage().contains("No content")) {
+ throw new RuntimeException(e);
+ }
+ } catch (Exception e) {
+ throw new RuntimeException(e);
+ }
- public String toString() {
- return "JsonTable";
+ if (jsonObj == null) {
+ list = new ArrayList<>();
+ jsonFieldMap.put("EmptyFileHasNoColumns", Boolean.TRUE);
Review comment:
Thanks for pointing that out. I didn't realize that logic was already in
there. This looks good to me!
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