[Transform] simplify class structure of indexer (#46306)

simplify transform task and indexer

 - remove redundant transform id
 - moving client data frame indexer (and builder) into a separate file

x-pack/plugin/data-frame/src/main/java/org/elasticsearch/xpack/dataframe/transforms/ClientDataFrameIndexerBuilder.java

@@ -0,0 +1,123 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License;
+ * you may not use this file except in compliance with the Elastic License.
+ */
+
+package org.elasticsearch.xpack.dataframe.transforms;
+
+import org.elasticsearch.client.Client;
+import org.elasticsearch.xpack.core.dataframe.transforms.DataFrameIndexerPosition;
+import org.elasticsearch.xpack.core.dataframe.transforms.DataFrameIndexerTransformStats;
+import org.elasticsearch.xpack.core.dataframe.transforms.DataFrameTransformCheckpoint;
+import org.elasticsearch.xpack.core.dataframe.transforms.DataFrameTransformConfig;
+import org.elasticsearch.xpack.core.dataframe.transforms.DataFrameTransformProgress;
+import org.elasticsearch.xpack.core.indexing.IndexerState;
+import org.elasticsearch.xpack.dataframe.checkpoint.CheckpointProvider;
+import org.elasticsearch.xpack.dataframe.checkpoint.DataFrameTransformsCheckpointService;
+import org.elasticsearch.xpack.dataframe.notifications.DataFrameAuditor;
+import org.elasticsearch.xpack.dataframe.persistence.DataFrameTransformsConfigManager;
+
+import java.util.Map;
+import java.util.concurrent.atomic.AtomicReference;
+
+class ClientDataFrameIndexerBuilder {
+    private Client client;
+    private DataFrameTransformsConfigManager transformsConfigManager;
+    private DataFrameTransformsCheckpointService transformsCheckpointService;
+    private DataFrameAuditor auditor;
+    private Map<String, String> fieldMappings;
+    private DataFrameTransformConfig transformConfig;
+    private DataFrameIndexerTransformStats initialStats;
+    private IndexerState indexerState = IndexerState.STOPPED;
+    private DataFrameIndexerPosition initialPosition;
+    private DataFrameTransformProgress progress;
+    private DataFrameTransformCheckpoint lastCheckpoint;
+    private DataFrameTransformCheckpoint nextCheckpoint;
+
+    ClientDataFrameIndexerBuilder() {
+        this.initialStats = new DataFrameIndexerTransformStats();
+    }
+
+    ClientDataFrameIndexer build(DataFrameTransformTask parentTask) {
+        CheckpointProvider checkpointProvider = transformsCheckpointService.getCheckpointProvider(transformConfig);
+
+        return new ClientDataFrameIndexer(this.transformsConfigManager,
+            checkpointProvider,
+            new AtomicReference<>(this.indexerState),
+            this.initialPosition,
+            this.client,
+            this.auditor,
+            this.initialStats,
+            this.transformConfig,
+            this.fieldMappings,
+            this.progress,
+            this.lastCheckpoint,
+            this.nextCheckpoint,
+            parentTask);
+    }
+
+    ClientDataFrameIndexerBuilder setClient(Client client) {
+        this.client = client;
+        return this;
+    }
+
+    ClientDataFrameIndexerBuilder setTransformsConfigManager(DataFrameTransformsConfigManager transformsConfigManager) {
+        this.transformsConfigManager = transformsConfigManager;
+        return this;
+    }
+
+    ClientDataFrameIndexerBuilder setTransformsCheckpointService(DataFrameTransformsCheckpointService transformsCheckpointService) {
+        this.transformsCheckpointService = transformsCheckpointService;
+        return this;
+    }
+
+    ClientDataFrameIndexerBuilder setAuditor(DataFrameAuditor auditor) {
+        this.auditor = auditor;
+        return this;
+    }
+
+    ClientDataFrameIndexerBuilder setFieldMappings(Map<String, String> fieldMappings) {
+        this.fieldMappings = fieldMappings;
+        return this;
+    }
+
+    ClientDataFrameIndexerBuilder setTransformConfig(DataFrameTransformConfig transformConfig) {
+        this.transformConfig = transformConfig;
+        return this;
+    }
+
+    DataFrameTransformConfig getTransformConfig() {
+        return this.transformConfig;
+    }
+
+    ClientDataFrameIndexerBuilder setInitialStats(DataFrameIndexerTransformStats initialStats) {
+        this.initialStats = initialStats;
+        return this;
+    }
+
+    ClientDataFrameIndexerBuilder setIndexerState(IndexerState indexerState) {
+        this.indexerState = indexerState;
+        return this;
+    }
+
+    ClientDataFrameIndexerBuilder setInitialPosition(DataFrameIndexerPosition initialPosition) {
+        this.initialPosition = initialPosition;
+        return this;
+    }
+
+    ClientDataFrameIndexerBuilder setProgress(DataFrameTransformProgress progress) {
+        this.progress = progress;
+        return this;
+    }
+
+    ClientDataFrameIndexerBuilder setLastCheckpoint(DataFrameTransformCheckpoint lastCheckpoint) {
+        this.lastCheckpoint = lastCheckpoint;
+        return this;
+    }
+
+    ClientDataFrameIndexerBuilder setNextCheckpoint(DataFrameTransformCheckpoint nextCheckpoint) {
+        this.nextCheckpoint = nextCheckpoint;
+        return this;
+    }
+}

x-pack/plugin/data-frame/src/main/java/org/elasticsearch/xpack/dataframe/transforms/DataFrameIndexer.java

@@ -117,6 +117,11 @@ public int getPageSize() {
         return pageSize;
     }
 
+    @Override
+    protected String getJobId() {
+        return transformConfig.getId();
+    }
+
     public DataFrameTransformConfig getConfig() {
         return transformConfig;
     }

x-pack/plugin/data-frame/src/main/java/org/elasticsearch/xpack/dataframe/transforms/DataFrameTransformPersistentTasksExecutor.java

@@ -130,8 +130,8 @@ protected void nodeOperation(AllocatedPersistentTask task, @Nullable DataFrameTr
         // We want the rest of the state to be populated in the task when it is loaded on the node so that users can force start it again
         // later if they want.
 
-        final DataFrameTransformTask.ClientDataFrameIndexerBuilder indexerBuilder =
-            new DataFrameTransformTask.ClientDataFrameIndexerBuilder(transformId)
+        final ClientDataFrameIndexerBuilder indexerBuilder =
+            new ClientDataFrameIndexerBuilder()
                 .setAuditor(auditor)
                 .setClient(client)
                 .setTransformsCheckpointService(dataFrameTransformsCheckpointService)
@@ -300,7 +300,7 @@ private void markAsFailed(DataFrameTransformTask task, String reason) {
     }
 
     private void startTask(DataFrameTransformTask buildTask,
-                           DataFrameTransformTask.ClientDataFrameIndexerBuilder indexerBuilder,
+                           ClientDataFrameIndexerBuilder indexerBuilder,
                            Long previousCheckpoint,
                            ActionListener<StartDataFrameTransformTaskAction.Response> listener) {
         buildTask.initializeIndexer(indexerBuilder);