Cpaulyz commented on code in PR #14791:
URL: https://github.com/apache/iotdb/pull/14791#discussion_r1984412551
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iotdb-api/udf-api/src/main/java/org/apache/iotdb/udf/api/relational/TableFunction.java:
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@@ -19,4 +19,69 @@
package org.apache.iotdb.udf.api.relational;
-public interface TableFunction extends SQLFunction {}
+import org.apache.iotdb.udf.api.exception.UDFException;
+import org.apache.iotdb.udf.api.relational.table.TableFunctionAnalysis;
+import
org.apache.iotdb.udf.api.relational.table.TableFunctionProcessorProvider;
+import org.apache.iotdb.udf.api.relational.table.argument.Argument;
+import org.apache.iotdb.udf.api.relational.table.argument.ScalarArgument;
+import org.apache.iotdb.udf.api.relational.table.argument.TableArgument;
+import
org.apache.iotdb.udf.api.relational.table.specification.ParameterSpecification;
+import
org.apache.iotdb.udf.api.relational.table.specification.ScalarParameterSpecification;
+import
org.apache.iotdb.udf.api.relational.table.specification.TableParameterSpecification;
+
+import java.util.List;
+import java.util.Map;
+
+public interface TableFunction extends SQLFunction {
+
+ /**
+ * This method is used to define the specification of the arguments required
by the table
+ * function. Each argument is described using a {@link
ParameterSpecification} object, which
+ * encapsulates details such as the argument name, whether it is required,
its default value (if
+ * any), etc.
+ *
+ * <p>The {@link ParameterSpecification} class is abstract and has two
concrete implementations:
+ *
+ * <ul>
+ * <li>{@link TableParameterSpecification}: Used for parameters specific
to table functions.
+ * <li>{@link ScalarParameterSpecification}: Used for parameters specific
to scalar functions.
+ * </ul>
+ *
+ * @return a list of {@link ParameterSpecification} objects describing the
function's arguments.
+ * The list should include all parameters that the table function
expects, along with their
+ * constraints and default values (if applicable).
+ */
+ List<ParameterSpecification> getArgumentsSpecifications();
+
+ /**
+ * This method is responsible for analyzing the provided arguments and
constructing a {@link
+ * TableFunctionAnalysis} object in runtime. During analysis, the method
should:
+ *
+ * <ul>
+ * <li>Extract values from scalar arguments (instances of {@link
ScalarArgument}) or extract
+ * table descriptions from table arguments (instances of {@link
TableArgument}).
+ * <li>Construct a {@link TableFunctionAnalysis} object that contains:
+ * <ul>
+ * <li>A description of proper columns.
Review Comment:
Good idea! I think it is an important knowledge for UDTF developer, so I
added this explaination at the top of `TableFunction` interface.
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