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Subject [GitHub] [flink] dianfu commented on a change in pull request #8561: [FLINK-12588][python] Add TableSchema for Python Table API.
Date Wed, 29 May 2019 11:56:42 GMT
dianfu commented on a change in pull request #8561: [FLINK-12588][python] Add TableSchema for
Python Table API.
URL: https://github.com/apache/flink/pull/8561#discussion_r288499091
 
 

 ##########
 File path: flink-python/pyflink/table/table_schema.py
 ##########
 @@ -0,0 +1,236 @@
+################################################################################
+#  Licensed to the Apache Software Foundation (ASF) under one
+#  or more contributor license agreements.  See the NOTICE file
+#  distributed with this work for additional information
+#  regarding copyright ownership.  The ASF licenses this file
+#  to you under the Apache License, Version 2.0 (the
+#  "License"); you may not use this file except in compliance
+#  with the License.  You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+#  Unless required by applicable law or agreed to in writing, software
+#  distributed under the License is distributed on an "AS IS" BASIS,
+#  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+#  See the License for the specific language governing permissions and
+# limitations under the License.
+################################################################################
+import sys
+
+from pyflink.java_gateway import get_gateway
+from pyflink.table.types import _to_java_type, _to_python_type
+from pyflink.util.utils import to_jarray
+
+if sys.version >= '3':
+    unicode = str
+
+
+class TableSchema(object):
+    """
+    A table schema that represents a table's structure with field names and data types.
+    """
+
+    def __init__(self, field_names=None, data_types=None, java_object=None):
+        if java_object is None:
+            gateway = get_gateway()
+            j_field_names = to_jarray(gateway.jvm.String, field_names)
+            j_data_types = to_jarray(gateway.jvm.TypeInformation,
+                                     [_to_java_type(item) for item in data_types])
+            self._j_table_schema = gateway.jvm.TableSchema(j_field_names, j_data_types)
+        else:
+            self._j_table_schema = java_object
+
+    def copy(self):
+        """
+        Returns a deep copy of the table schema.
+
+        :return: A deep copy of the table schema.
+        """
+        return TableSchema(java_object=self._j_table_schema.copy())
+
+    def get_field_types(self):
+        """
+        Returns all field data types as an array.
+
+        .. note::
+            Deprecated.
+            Use :func:`pyflink.table.table_schema.TableSchema.get_field_data_types` instead.
+
+
+        :return: A list of all field data types.
+        """
+        return [_to_python_type(item) for item in self._j_table_schema.getFieldTypes()]
+
+    def get_field_data_types(self):
+        """
+        Returns all field data types as an array.
+
+        :return: A list of all field data types.
+        """
+        return [_to_python_type(item) for item in self._j_table_schema.getFieldDataTypes()]
+
+    def get_field_data_type(self, field):
+        """
+        Returns the specified data type for the given field index or field name.
+
+        :param field: The index of the field or the name of the field.
+        :return: The specified data type.
+        """
+        if not isinstance(field, (int, str, unicode)):
+            raise TypeError("not supported data type: %s" % type(field))
+        optional_result = self._j_table_schema.getFieldDataType(field)
+        if optional_result.isPresent():
+            return _to_python_type(optional_result.get())
+        else:
+            return None
+
+    def get_field_type(self, field):
+        """
+        Returns the specified data type for the given field index or field name.
+
+        .. note::
+            Deprecated.
+            Use :func:`pyflink.table.table_schema.TableSchema.get_field_data_type` instead.
+
+        :param field: The index of the field or the name of the field.
+        :return: The specified data type.
+        """
+        if not isinstance(field, (int, str, unicode)):
+            raise TypeError("not supported data type: %s" % type(field))
+        optional_result = self._j_table_schema.getFieldType(field)
+        if optional_result.isPresent():
+            return _to_python_type(optional_result.get())
+        else:
+            return None
+
+    def get_field_count(self):
+        """
+        Returns the number of fields.
+
+        :return: The number of fields.
+        """
+        return self._j_table_schema.getFieldCount()
+
+    def get_field_names(self):
+        """
+        Returns all field names as a list.
+
+        :return: The list of all field names.
+        """
+        return list(self._j_table_schema.getFieldNames())
+
+    def get_field_name(self, field_index):
+        """
+        Returns the specified name for the given field index.
+
+        :param field_index: The index of the field.
+        :return: The field name.
+        """
+        optional_result = self._j_table_schema.getFieldName(field_index)
+        if optional_result.isPresent():
+            return optional_result.get()
+        else:
+            return None
+
+    def to_row_data_type(self):
+        """
+        Converts a table schema into a (nested) data type describing a
+        :func:`pyflink.table.types.DataTypes.ROW`.
+
+        :return: The row data type.
+        """
+        return _to_python_type(self._j_table_schema.toRowDataType())
+
+    def to_row_type(self):
+        """
+        Converts a table schema into a (nested) data type describing a
+        :func:`pyflink.table.types.DataTypes.ROW`.
+
+        .. note::
+            Deprecated.
+            Use :func:`pyflink.table.table_schema.TableSchema.to_row_data_type` instead.
+
+        :return: The row data type.
+        """
+        return _to_python_type(self._j_table_schema.toRowType())
+
+    def __repr__(self):
+        if self._j_table_schema is not None:
+            return self._j_table_schema.toString()
+        else:
+            return super(TableSchema, self).__repr__()
+
+    def __str__(self):
+        if self._j_table_schema is not None:
+            return self._j_table_schema.toString()
+        else:
+            return super(TableSchema, self).__str__()
+
+    def __eq__(self, other):
+        return isinstance(other, self.__class__) and self._j_table_schema == other._j_table_schema
+
+    def __hash__(self):
+        if self._j_table_schema is not None:
+            return self._j_table_schema.hashCode()
+        else:
+            return super(TableSchema, self).__hash__()
+
+    def __ne__(self, other):
+        return not self.__eq__(other)
+
+    @classmethod
+    def from_type_info(cls, data_type):
+        """
+        Creates a table schema from a :class:`DataType` instance. If the type information
is
+        a composite type, the field names and types for the composite type are used to
+        construct the :class:`TableSchema` instance. Otherwise, a table schema with a single
field
+        is created. The field name is "f0" and the field type the provided type.
+
+        ..note::
+            Deprecated.
+            This method will be removed soon. Use :class:`DataTypes` to declare types.
+
+        :param data_type: The data type from which the table schema is generated.
+        :return: The table schema that was generated from the given :class:`DataType`.
+        """
+        gateway = get_gateway()
+        return TableSchema(
+            java_object=gateway.jvm.TableSchema.fromTypeInfo(_to_java_type(data_type)))
+
+    @classmethod
+    def builder(cls):
+        return TableSchema.Builder()
+
+    class Builder(object):
+        """
+        Builder for creating a :class:`TableSchema`.
+
 
 Review comment:
   Remove the empty line.

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