Delete AccumulatorTarget

Author: wu-hui

google-cloud-firestore/src/main/java/com/google/cloud/firestore/AggregateQuery.java

@@ -25,7 +25,7 @@
 import com.google.api.gax.rpc.StatusCode;
 import com.google.api.gax.rpc.StreamController;
 import com.google.cloud.Timestamp;
-import com.google.cloud.firestore.pipeline.expressions.AccumulatorTarget;
+import com.google.cloud.firestore.pipeline.expressions.ExprWithAlias;
 import com.google.cloud.firestore.v1.FirestoreSettings;
 import com.google.common.collect.ImmutableMap;
 import com.google.firestore.v1.RunAggregationQueryRequest;
@@ -75,7 +75,7 @@ public Pipeline pipeline() {
         .aggregate(
             this.aggregateFieldList.stream()
                 .map(PipelineUtils::toPipelineAggregatorTarget)
-                .toArray(AccumulatorTarget[]::new));
+                .toArray(ExprWithAlias[]::new));
   }
 
   /**

google-cloud-firestore/src/main/java/com/google/cloud/firestore/Pipeline.java

@@ -9,7 +9,8 @@
 import com.google.api.gax.rpc.StreamController;
 import com.google.cloud.Timestamp;
 import com.google.cloud.firestore.pipeline.PaginatingPipeline;
-import com.google.cloud.firestore.pipeline.expressions.AccumulatorTarget;
+import com.google.cloud.firestore.pipeline.expressions.Accumulator;
+import com.google.cloud.firestore.pipeline.expressions.ExprWithAlias;
 import com.google.cloud.firestore.pipeline.expressions.Field;
 import com.google.cloud.firestore.pipeline.expressions.FilterCondition;
 import com.google.cloud.firestore.pipeline.expressions.Ordering;
@@ -156,7 +157,7 @@ public Pipeline limit(int limit) {
   }
 
   @BetaApi
-  public Pipeline aggregate(AccumulatorTarget... accumulators) {
+  public Pipeline aggregate(ExprWithAlias<Accumulator>... accumulators) {
     return new Pipeline(
         this.db,
         ImmutableList.<Stage>builder()

google-cloud-firestore/src/main/java/com/google/cloud/firestore/PipelineUtils.java

@@ -14,6 +14,7 @@
 import com.google.cloud.firestore.Query.LimitType;
 import com.google.cloud.firestore.Query.UnaryFilterInternal;
 import com.google.cloud.firestore.pipeline.PaginatingPipeline;
+import com.google.cloud.firestore.pipeline.expressions.Accumulator;
 import com.google.cloud.firestore.pipeline.expressions.AccumulatorTarget;
 import com.google.cloud.firestore.pipeline.expressions.Expr;
 import com.google.cloud.firestore.pipeline.expressions.ExprWithAlias;
@@ -158,7 +159,7 @@ static Pipeline toPaginatedPipeline(
   }
 
   @InternalApi
-  static AccumulatorTarget toPipelineAggregatorTarget(AggregateField f) {
+  static ExprWithAlias<Accumulator> toPipelineAggregatorTarget(AggregateField f) {
     String operator = f.getOperator();
     String fieldPath = f.getFieldPath();
 

google-cloud-firestore/src/main/java/com/google/cloud/firestore/pipeline/expressions/Accumulator.java

@@ -6,7 +6,7 @@
 public interface Accumulator extends Expr {
   @BetaApi
   @Override
-  default AccumulatorTarget as(String fieldName) {
-    return new AccumulatorTarget(this, fieldName, false);
+  default ExprWithAlias<Accumulator> as(String fieldName) {
+    return new ExprWithAlias<>(this, fieldName);
   }
 }

google-cloud-firestore/src/main/java/com/google/cloud/firestore/pipeline/expressions/ExprWithAlias.java

@@ -3,13 +3,13 @@
 import com.google.api.core.InternalApi;
 
 @InternalApi
-public final class ExprWithAlias implements Selectable {
+public final class ExprWithAlias<T extends Expr> implements Selectable {
 
   private final String alias;
-  private final Expr expr;
+  private final T expr;
 
   @InternalApi
-  ExprWithAlias(Expr expr, String alias) {
+  ExprWithAlias(T expr, String alias) {
     this.expr = expr;
     this.alias = alias;
   }
@@ -20,7 +20,7 @@ public String getAlias() {
   }
 
   @InternalApi
-  public Expr getExpr() {
+  public T getExpr() {
     return expr;
   }
 }

google-cloud-firestore/src/main/java/com/google/cloud/firestore/pipeline/stages/Aggregate.java

@@ -4,8 +4,8 @@
 import com.google.api.core.InternalApi;
 import com.google.cloud.firestore.PipelineUtils;
 import com.google.cloud.firestore.pipeline.expressions.Accumulator;
-import com.google.cloud.firestore.pipeline.expressions.AccumulatorTarget;
 import com.google.cloud.firestore.pipeline.expressions.Expr;
+import com.google.cloud.firestore.pipeline.expressions.ExprWithAlias;
 import com.google.cloud.firestore.pipeline.expressions.Selectable;
 import java.util.Arrays;
 import java.util.Collections;
@@ -30,7 +30,7 @@ public Aggregate withGroups(Selectable... selectables) {
   }
 
   @BetaApi
-  public static Aggregate withAccumulators(AccumulatorTarget... accumulators) {
+  public static Aggregate withAccumulators(ExprWithAlias<Accumulator>... accumulators) {
     if (accumulators.length == 0) {
       throw new IllegalArgumentException(
           "Must specify at least one accumulator for aggregate() stage. There is a distinct() stage if only distinct group values are needed.");
@@ -39,9 +39,7 @@ public static Aggregate withAccumulators(AccumulatorTarget... accumulators) {
     return new Aggregate(
         Collections.emptyMap(),
         Arrays.stream(accumulators)
-            .collect(
-                Collectors.toMap(
-                    AccumulatorTarget::getFieldName, AccumulatorTarget::getAccumulator)));
+            .collect(Collectors.toMap(ExprWithAlias::getAlias, ExprWithAlias::getExpr)));
   }
 
   private Aggregate(Map<String, Expr> groups, Map<String, Accumulator> accumulators) {