[Feature][transform] Add a module to set default value for null field

docs/en/transform/nulltf.md

@@ -0,0 +1,73 @@
+# Nulltf
+
+## Description
+
+set default value for null field
+
+:::tip
+
+This transform only supported by engine Spark.
+
+:::
+
+## Options
+
+| name                | type    | required | default value |
+| ------------------- | ------- | -------- | ------------- |
+| fields              | array   | no       | -             |
+
+### fields [list]
+
+A list of fields whose default value will be set. 
+The default value of the field can be set in the form of "field:value", If no set, the default value will be set according to the field type.
+
+## Examples
+
+the configuration
+
+```bash
+  nulltf {
+      fields {
+          name: "",
+          price: 0,
+          num: 100,
+          flag: false,
+          dt_timestamp: "2022-05-18 13:51:40.603",
+          dt_date: "2022-05-19"
+      }
+  }
+```
+
+before use nulltf transform
+
+```bash
++-----+-----+----+-----+--------------------+----------+
+| name|price| num| flag|        dt_timestamp|   dt_date|
++-----+-----+----+-----+--------------------+----------+
+|名称1| 22.5| 100|false|2022-05-20 14:34:...|2022-05-20|
+| null| 22.5| 100|false|2022-05-20 14:35:...|2022-05-20|
+|名称1| null| 100|false|2022-05-20 14:35:...|2022-05-20|
+|名称1| 22.5|null|false|2022-05-20 14:36:...|2022-05-20|
+|名称1| 22.5| 100| null|2022-05-20 14:36:...|2022-05-20|
+|名称1| 22.5| 100|false|                null|2022-05-20|
+|名称1| 22.5| 100|false|2022-05-20 14:37:...|      null|
++-----+-----+----+-----+--------------------+----------+
+```
+
+after use nulltf transform
+
+```bash
++-----+-----+----+-----+--------------------+----------+
+| name|price| num| flag|        dt_timestamp|   dt_date|
++-----+-----+----+-----+--------------------+----------+
+|名称1| 22.5|100|false|2022-05-20 14:34:...|2022-05-20|
+|     | 22.5|100|false|2022-05-20 14:35:...|2022-05-20|
+|名称1|  0.0|100|false|2022-05-20 14:35:...|2022-05-20|
+|名称1| 22.5|100|false|2022-05-20 14:36:...|2022-05-20|
+|名称1| 22.5|100|false|2022-05-20 14:36:...|2022-05-20|
+|名称1| 22.5|100|false|2022-05-18 13:51:...|2022-05-20|
+|名称1| 22.5|100|false|2022-05-20 14:37:...|2022-05-19|
++-----+-----+---+-----+--------------------+----------+
+```
+
+

seatunnel-core/seatunnel-core-spark/pom.xml

@@ -81,6 +81,12 @@
             <version>${project.version}</version>
         </dependency>
 
+        <dependency>
+            <groupId>org.apache.seatunnel</groupId>
+            <artifactId>seatunnel-transform-spark-nulltf</artifactId>
+            <version>${project.version}</version>
+        </dependency>
+
         <dependency>
             <groupId>org.apache.seatunnel</groupId>
             <artifactId>seatunnel-transform-spark-null-rate</artifactId>

seatunnel-transforms/seatunnel-transforms-spark/pom.xml

@@ -36,6 +36,7 @@
         <module>seatunnel-transform-spark-replace</module>
         <module>seatunnel-transform-spark-uuid</module>
         <module>seatunnel-transform-spark-sql</module>
+        <module>seatunnel-transform-spark-nulltf</module>
         <module>seatunnel-transform-spark-null-rate</module>
     </modules>
 

seatunnel-transforms/seatunnel-transforms-spark/seatunnel-transform-spark-nulltf/pom.xml

@@ -0,0 +1,51 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--
+
+    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.
+
+-->
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <parent>
+        <groupId>org.apache.seatunnel</groupId>
+        <artifactId>seatunnel-transforms-spark</artifactId>
+        <version>${revision}</version>
+    </parent>
+    <modelVersion>4.0.0</modelVersion>
+
+    <artifactId>seatunnel-transform-spark-nulltf</artifactId>
+
+    <dependencies>
+        <dependency>
+            <groupId>org.apache.seatunnel</groupId>
+            <artifactId>seatunnel-api-spark</artifactId>
+            <version>${project.version}</version>
+            <scope>provided</scope>
+        </dependency>
+
+        <dependency>
+            <groupId>org.apache.spark</groupId>
+            <artifactId>spark-core_${scala.binary.version}</artifactId>
+        </dependency>
+
+        <dependency>
+            <groupId>org.apache.spark</groupId>
+            <artifactId>spark-sql_${scala.binary.version}</artifactId>
+        </dependency>
+    </dependencies>
+
+</project>

seatunnel-transforms/seatunnel-transforms-spark/seatunnel-transform-spark-nulltf/src/main/resources/META-INF/services/org.apache.seatunnel.spark.BaseSparkTransform

@@ -0,0 +1,18 @@
+#
+# 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.
+#
+
+org.apache.seatunnel.spark.transform.Nulltf

seatunnel-transforms/seatunnel-transforms-spark/seatunnel-transform-spark-nulltf/src/main/scala/org/apache/seatunnel/spark/transform/Nulltf.scala

@@ -0,0 +1,111 @@
+/*
+ * 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.
+ */
+
+package org.apache.seatunnel.spark.transform
+
+import java.sql.Timestamp
+
+import org.apache.seatunnel.common.config.CheckConfigUtil.checkAllExists
+import org.apache.seatunnel.common.config.CheckResult
+import org.apache.seatunnel.spark.{BaseSparkTransform, SparkEnvironment}
+import org.apache.seatunnel.spark.transform.NulltfConfig._
+import org.apache.spark.sql.catalyst.encoders.RowEncoder
+import org.apache.spark.sql.types.{BooleanType, DataType, DateType, DoubleType, FloatType, IntegerType, LongType, ShortType, StringType, TimestampType}
+import org.apache.spark.sql.{Dataset, Row}
+
+import scala.collection.JavaConversions._
+import scala.collection.mutable
+import scala.collection.mutable.{ArrayBuffer, Buffer, HashMap}
+
+class Nulltf extends BaseSparkTransform {
+
+
+  override def process(df: Dataset[Row], env: SparkEnvironment): Dataset[Row] = {
+
+    var fieldNameDefault = new mutable.HashMap[String, String]()
+    if (!config.getConfig(FIELDS).isEmpty) {
+      config.getConfig(FIELDS).entrySet().foreach(kv => {
+        fieldNameDefault += (kv.getKey -> kv.getValue.unwrapped().toString)
+      })
+    }
+
+    df.mapPartitions(iter => {
+      var result = ArrayBuffer[Row]()
+      while (iter.hasNext) {
+        val row = iter.next()
+        val fieldSeq = mutable.Buffer[Any]()
+        for (i <- 0 until row.size) {
+          val newField = if (row.isNullAt(i)) {
+            val fieldName = row.schema.fields.apply(i).name
+            val fieldType = row.schema.fields.apply(i).dataType
+
+            val temp = fieldNameDefault.get(fieldName)
+            if (temp.isDefined) {
+              if (temp.get == null) getDefaultValueByDataType(fieldType) else transfromStringToRightType(temp.get, fieldType)
+            } else {
+              getDefaultValueByDataType(fieldType)
+            }
+          } else row.get(i)
+
+          fieldSeq += newField
+        }
+        val newRow = Row.fromSeq(fieldSeq)
+        result += newRow
+      }
+      result.iterator
+    })(RowEncoder.apply(df.schema))
+
+  }
+
+  override def checkConfig(): CheckResult = {
+    checkAllExists(config)
+  }
+
+  override def getPluginName: String = PLUGIN_NAME
+
+  private def getDefaultValueByDataType(dataType: DataType): Any = {
+    dataType match {
+      case StringType => ""
+      case ShortType => 0
+      case IntegerType => 0
+      case FloatType => 0f
+      case DoubleType => 0d
+      case LongType => 0L
+      case BooleanType => false
+      case DateType => new java.sql.Date(System.currentTimeMillis())
+      case TimestampType => new Timestamp(System.currentTimeMillis())
+      case _ => null
+    }
+  }
+
+  private def transfromStringToRightType(value: String, dataType: DataType): Any = {
+    dataType match {
+      case StringType => value
+      case ShortType => java.lang.Short.valueOf(value)
+      case IntegerType => java.lang.Integer.valueOf(value)
+      case FloatType => java.lang.Float.valueOf(value)
+      case DoubleType => java.lang.Double.valueOf(value)
+      case LongType => java.lang.Long.valueOf(value)
+      case BooleanType => java.lang.Boolean.valueOf(value)
+      case DateType => java.sql.Date.valueOf(value)
+      case TimestampType => java.sql.Timestamp.valueOf(value)
+      case _ => value
+    }
+  }
+
+
+}

seatunnel-transforms/seatunnel-transforms-spark/seatunnel-transform-spark-nulltf/src/main/scala/org/apache/seatunnel/spark/transform/NulltfConfig.scala

@@ -0,0 +1,25 @@
+/*
+ * 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.
+ */
+
+package org.apache.seatunnel.spark.transform
+
+object NulltfConfig {
+  val PLUGIN_NAME = "nulltf"
+
+  val FIELDS = "fields"
+
+}