Support cast function in SQL (#926)

* init

* update

* update doc

* update doc

* update doc

* fix breaking IT

core/src/main/java/com/amazon/opendistroforelasticsearch/sql/analysis/ExpressionAnalyzer.java

@@ -22,6 +22,7 @@
 import com.amazon.opendistroforelasticsearch.sql.ast.expression.AllFields;
 import com.amazon.opendistroforelasticsearch.sql.ast.expression.And;
 import com.amazon.opendistroforelasticsearch.sql.ast.expression.Case;
+import com.amazon.opendistroforelasticsearch.sql.ast.expression.Cast;
 import com.amazon.opendistroforelasticsearch.sql.ast.expression.Compare;
 import com.amazon.opendistroforelasticsearch.sql.ast.expression.EqualTo;
 import com.amazon.opendistroforelasticsearch.sql.ast.expression.Field;
@@ -67,6 +68,13 @@ public class ExpressionAnalyzer extends AbstractNodeVisitor<Expression, Analysis
   private final BuiltinFunctionRepository repository;
   private final DSL dsl;
 
+  @Override
+  public Expression visitCast(Cast node, AnalysisContext context) {
+    final Expression expression = node.getExpression().accept(this, context);
+    return (Expression) repository
+        .compile(node.convertFunctionName(), Collections.singletonList(expression));
+  }
+
   public ExpressionAnalyzer(
       BuiltinFunctionRepository repository) {
     this.repository = repository;

core/src/main/java/com/amazon/opendistroforelasticsearch/sql/ast/AbstractNodeVisitor.java

@@ -22,6 +22,7 @@
 import com.amazon.opendistroforelasticsearch.sql.ast.expression.Argument;
 import com.amazon.opendistroforelasticsearch.sql.ast.expression.AttributeList;
 import com.amazon.opendistroforelasticsearch.sql.ast.expression.Case;
+import com.amazon.opendistroforelasticsearch.sql.ast.expression.Cast;
 import com.amazon.opendistroforelasticsearch.sql.ast.expression.Compare;
 import com.amazon.opendistroforelasticsearch.sql.ast.expression.EqualTo;
 import com.amazon.opendistroforelasticsearch.sql.ast.expression.Field;
@@ -226,6 +227,10 @@ public T visitWhen(When node, C context) {
     return visitChildren(node, context);
   }
 
+  public T visitCast(Cast node, C context) {
+    return visitChildren(node, context);
+  }
+
   public T visitUnresolvedArgument(UnresolvedArgument node, C context) {
     return visitChildren(node, context);
   }

core/src/main/java/com/amazon/opendistroforelasticsearch/sql/ast/dsl/AstDSL.java

@@ -21,6 +21,7 @@
 import com.amazon.opendistroforelasticsearch.sql.ast.expression.And;
 import com.amazon.opendistroforelasticsearch.sql.ast.expression.Argument;
 import com.amazon.opendistroforelasticsearch.sql.ast.expression.Case;
+import com.amazon.opendistroforelasticsearch.sql.ast.expression.Cast;
 import com.amazon.opendistroforelasticsearch.sql.ast.expression.Compare;
 import com.amazon.opendistroforelasticsearch.sql.ast.expression.DataType;
 import com.amazon.opendistroforelasticsearch.sql.ast.expression.EqualTo;
@@ -221,6 +222,10 @@ public UnresolvedExpression caseWhen(UnresolvedExpression caseValueExpr,
     return new Case(caseValueExpr, Arrays.asList(whenClauses), elseClause);
   }
 
+  public UnresolvedExpression cast(UnresolvedExpression expr, Literal type) {
+    return new Cast(expr, type);
+  }
+
   public When when(UnresolvedExpression condition, UnresolvedExpression result) {
     return new When(condition, result);
   }

core/src/main/java/com/amazon/opendistroforelasticsearch/sql/ast/expression/Cast.java

@@ -0,0 +1,98 @@
+/*
+ *
+ *    Copyright 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ *
+ *    Licensed under the Apache License, Version 2.0 (the "License").
+ *    You may not use this file except in compliance with the License.
+ *    A copy of the License is located at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *    or in the "license" file accompanying this file. This file 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 com.amazon.opendistroforelasticsearch.sql.ast.expression;
+
+import static com.amazon.opendistroforelasticsearch.sql.expression.function.BuiltinFunctionName.CAST_TO_BOOLEAN;
+import static com.amazon.opendistroforelasticsearch.sql.expression.function.BuiltinFunctionName.CAST_TO_DATE;
+import static com.amazon.opendistroforelasticsearch.sql.expression.function.BuiltinFunctionName.CAST_TO_DOUBLE;
+import static com.amazon.opendistroforelasticsearch.sql.expression.function.BuiltinFunctionName.CAST_TO_FLOAT;
+import static com.amazon.opendistroforelasticsearch.sql.expression.function.BuiltinFunctionName.CAST_TO_INT;
+import static com.amazon.opendistroforelasticsearch.sql.expression.function.BuiltinFunctionName.CAST_TO_LONG;
+import static com.amazon.opendistroforelasticsearch.sql.expression.function.BuiltinFunctionName.CAST_TO_STRING;
+import static com.amazon.opendistroforelasticsearch.sql.expression.function.BuiltinFunctionName.CAST_TO_TIME;
+import static com.amazon.opendistroforelasticsearch.sql.expression.function.BuiltinFunctionName.CAST_TO_TIMESTAMP;
+
+import com.amazon.opendistroforelasticsearch.sql.ast.AbstractNodeVisitor;
+import com.amazon.opendistroforelasticsearch.sql.ast.Node;
+import com.amazon.opendistroforelasticsearch.sql.expression.function.FunctionName;
+import com.google.common.collect.ImmutableMap;
+import java.util.Collections;
+import java.util.List;
+import java.util.Locale;
+import java.util.Map;
+import lombok.AllArgsConstructor;
+import lombok.EqualsAndHashCode;
+import lombok.Getter;
+import lombok.ToString;
+
+/**
+ * AST node that represents Cast clause.
+ */
+@AllArgsConstructor
+@EqualsAndHashCode(callSuper = false)
+@Getter
+@ToString
+public class Cast extends UnresolvedExpression {
+
+  private static Map<String, FunctionName> CONVERTED_TYPE_FUNCTION_NAME_MAP =
+      new ImmutableMap.Builder<String, FunctionName>()
+          .put("string", CAST_TO_STRING.getName())
+          .put("int", CAST_TO_INT.getName())
+          .put("long", CAST_TO_LONG.getName())
+          .put("float", CAST_TO_FLOAT.getName())
+          .put("double", CAST_TO_DOUBLE.getName())
+          .put("boolean", CAST_TO_BOOLEAN.getName())
+          .put("date", CAST_TO_DATE.getName())
+          .put("time", CAST_TO_TIME.getName())
+          .put("timestamp", CAST_TO_TIMESTAMP.getName())
+          .build();
+
+  /**
+   * The source expression cast from.
+   */
+  private final UnresolvedExpression expression;
+
+  /**
+   * Expression that represents ELSE statement result.
+   */
+  private final UnresolvedExpression convertedType;
+
+  /**
+   * Get the converted type.
+   *
+   * @return converted type
+   */
+  public FunctionName convertFunctionName() {
+    String type = convertedType.toString().toLowerCase(Locale.ROOT);
+    if (CONVERTED_TYPE_FUNCTION_NAME_MAP.containsKey(type)) {
+      return CONVERTED_TYPE_FUNCTION_NAME_MAP.get(type);
+    } else {
+      throw new IllegalStateException("unsupported cast type: " + type);
+    }
+  }
+
+  @Override
+  public List<? extends Node> getChild() {
+    return Collections.singletonList(expression);
+  }
+
+  @Override
+  public <T, C> T accept(AbstractNodeVisitor<T, C> nodeVisitor, C context) {
+    return nodeVisitor.visitCast(this, context);
+  }
+}

core/src/main/java/com/amazon/opendistroforelasticsearch/sql/expression/DSL.java

@@ -523,4 +523,49 @@ public FunctionExpression interval(Expression value, Expression unit) {
     return (FunctionExpression) repository.compile(
         BuiltinFunctionName.INTERVAL.getName(), Arrays.asList(value, unit));
   }
+
+  public FunctionExpression castString(Expression value) {
+    return (FunctionExpression) repository
+        .compile(BuiltinFunctionName.CAST_TO_STRING.getName(), Arrays.asList(value));
+  }
+
+  public FunctionExpression castInt(Expression value) {
+    return (FunctionExpression) repository
+        .compile(BuiltinFunctionName.CAST_TO_INT.getName(), Arrays.asList(value));
+  }
+
+  public FunctionExpression castLong(Expression value) {
+    return (FunctionExpression) repository
+        .compile(BuiltinFunctionName.CAST_TO_LONG.getName(), Arrays.asList(value));
+  }
+
+  public FunctionExpression castFloat(Expression value) {
+    return (FunctionExpression) repository
+        .compile(BuiltinFunctionName.CAST_TO_FLOAT.getName(), Arrays.asList(value));
+  }
+
+  public FunctionExpression castDouble(Expression value) {
+    return (FunctionExpression) repository
+        .compile(BuiltinFunctionName.CAST_TO_DOUBLE.getName(), Arrays.asList(value));
+  }
+
+  public FunctionExpression castBoolean(Expression value) {
+    return (FunctionExpression) repository
+        .compile(BuiltinFunctionName.CAST_TO_BOOLEAN.getName(), Arrays.asList(value));
+  }
+
+  public FunctionExpression castDate(Expression value) {
+    return (FunctionExpression) repository
+        .compile(BuiltinFunctionName.CAST_TO_DATE.getName(), Arrays.asList(value));
+  }
+
+  public FunctionExpression castTime(Expression value) {
+    return (FunctionExpression) repository
+        .compile(BuiltinFunctionName.CAST_TO_TIME.getName(), Arrays.asList(value));
+  }
+
+  public FunctionExpression castTimestamp(Expression value) {
+    return (FunctionExpression) repository
+        .compile(BuiltinFunctionName.CAST_TO_TIMESTAMP.getName(), Arrays.asList(value));
+  }
 }

core/src/main/java/com/amazon/opendistroforelasticsearch/sql/expression/config/ExpressionConfig.java

@@ -22,6 +22,7 @@
 import com.amazon.opendistroforelasticsearch.sql.expression.function.BuiltinFunctionRepository;
 import com.amazon.opendistroforelasticsearch.sql.expression.operator.arthmetic.ArithmeticFunction;
 import com.amazon.opendistroforelasticsearch.sql.expression.operator.arthmetic.MathematicalFunction;
+import com.amazon.opendistroforelasticsearch.sql.expression.operator.convert.TypeCastOperator;
 import com.amazon.opendistroforelasticsearch.sql.expression.operator.predicate.BinaryPredicateOperator;
 import com.amazon.opendistroforelasticsearch.sql.expression.operator.predicate.UnaryPredicateOperator;
 import com.amazon.opendistroforelasticsearch.sql.expression.text.TextFunction;
@@ -51,6 +52,7 @@ public BuiltinFunctionRepository functionRepository() {
     IntervalClause.register(builtinFunctionRepository);
     WindowFunctions.register(builtinFunctionRepository);
     TextFunction.register(builtinFunctionRepository);
+    TypeCastOperator.register(builtinFunctionRepository);
     return builtinFunctionRepository;
   }
 

core/src/main/java/com/amazon/opendistroforelasticsearch/sql/expression/function/BuiltinFunctionName.java

@@ -142,7 +142,20 @@ public enum BuiltinFunctionName {
   RANK(FunctionName.of("rank")),
   DENSE_RANK(FunctionName.of("dense_rank")),
 
-  INTERVAL(FunctionName.of("interval"));
+  INTERVAL(FunctionName.of("interval")),
+
+  /**
+   * Data Type Convert Function.
+   */
+  CAST_TO_STRING(FunctionName.of("cast_to_string")),
+  CAST_TO_INT(FunctionName.of("cast_to_int")),
+  CAST_TO_LONG(FunctionName.of("cast_to_long")),
+  CAST_TO_FLOAT(FunctionName.of("cast_to_float")),
+  CAST_TO_DOUBLE(FunctionName.of("cast_to_double")),
+  CAST_TO_BOOLEAN(FunctionName.of("cast_to_boolean")),
+  CAST_TO_DATE(FunctionName.of("cast_to_date")),
+  CAST_TO_TIME(FunctionName.of("cast_to_time")),
+  CAST_TO_TIMESTAMP(FunctionName.of("cast_to_timestamp"));
 
   private final FunctionName name;