#94: Refactored the Cast function

exasol · Oct 22, 2020 · 21814a2 · 21814a2
1 parent c940c39
commit 21814a2
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Showing 8 changed files with 44 additions and 47 deletions.
diff --git a/src/main/java/com/exasol/sql/dql/select/Select.java b/src/main/java/com/exasol/sql/dql/select/Select.java
@@ -3,15 +3,10 @@
 import java.util.ArrayList;
 import java.util.List;
 
-import com.exasol.datatype.type.DataType;
-import com.exasol.sql.AbstractFragment;
-import com.exasol.sql.ColumnsDefinition;
-import com.exasol.sql.DerivedColumn;
-import com.exasol.sql.SqlStatement;
+import com.exasol.sql.*;
 import com.exasol.sql.expression.*;
 import com.exasol.sql.expression.function.Function;
 import com.exasol.sql.expression.function.FunctionName;
-import com.exasol.sql.expression.function.exasol.ExasolCastFunction;
 
 /**
  * This class implements an SQL {@link Select} statement.
@@ -60,7 +55,7 @@ public Select field(final String... names) {
     /**
      * Add a function.
      * 
-     * @param functionName     a name of function
+     * @param functionName     name of function
      * @param valueExpressions zero or more value expression
      * @return <code>this</code> instance for fluent programming
      */
@@ -85,28 +80,26 @@ public Select function(final FunctionName functionName, final String derivedColu
     }
 
     /**
-     * Add a cast function.
+     * Add a function.
      *
-     * @param value value to cast
-     * @param type  type to cast the value to
+     * @param function          function
+     * @param derivedColumnName name under which you can refer to the derived column
      * @return <code>this</code> instance for fluent programming
      */
-    public Select cast(final ValueExpression value, final DataType type) {
-        return this.cast(value, type, "");
+    public Select function(final Function function, final String derivedColumnName) {
+        final DerivedColumn derivedColumn = new DerivedColumn(this, function, derivedColumnName);
+        this.derivedColumns.add(derivedColumn);
+        return this;
     }
 
     /**
-     * Add a cast function.
-     * 
-     * @param value             value to cast
-     * @param type              type to cast the value to
-     * @param derivedColumnName name under which you can refer to the derived column
+     * Add a function.
+     *
+     * @param function function
      * @return <code>this</code> instance for fluent programming
      */
-    public Select cast(final ValueExpression value, final DataType type, final String derivedColumnName) {
-        final Function castFunction = ExasolCastFunction.of(value, type);
-        final DerivedColumn derivedColumn = new DerivedColumn(this, castFunction, derivedColumnName);
-        this.derivedColumns.add(derivedColumn);
+    public Select function(final Function function) {
+        function(function, "");
         return this;
     }
 

diff --git a/src/main/java/com/exasol/sql/expression/ValueExpressionVisitor.java b/src/main/java/com/exasol/sql/expression/ValueExpressionVisitor.java
@@ -1,9 +1,7 @@
 package com.exasol.sql.expression;
 
 import com.exasol.sql.UnnamedPlaceholder;
-import com.exasol.sql.expression.function.exasol.ExasolCastFunction;
-import com.exasol.sql.expression.function.exasol.ExasolFunction;
-import com.exasol.sql.expression.function.exasol.ExasolUdf;
+import com.exasol.sql.expression.function.exasol.*;
 
 /**
  * Visitor interface for a {@link BooleanTerm}.
@@ -43,5 +41,5 @@ public interface ValueExpressionVisitor {
 
     public void visit(BooleanExpression booleanExpression);
 
-    public void visit(ExasolCastFunction castFunction);
+    public void visit(ExasolFunctionCast castFunction);
 }
diff --git a/...ction/exasol/ExasolAnalyticFunctions.java → ...nction/exasol/ExasolAnalyticFunction.java b/...ction/exasol/ExasolAnalyticFunctions.java → ...nction/exasol/ExasolAnalyticFunction.java
@@ -14,6 +14,6 @@
  * <a href="https://github.com/exasol/sql-statement-builder/issues/72"> github issue # 72</a>.
  * </p>
  */
-public enum ExasolAnalyticFunctions implements FunctionName {
+public enum ExasolAnalyticFunction implements FunctionName {
     ANY, EVERY, LISTAGG
 }
diff --git a/src/main/java/com/exasol/sql/expression/function/exasol/ExasolFunction.java b/src/main/java/com/exasol/sql/expression/function/exasol/ExasolFunction.java
@@ -2,6 +2,7 @@
 
 import java.util.*;
 
+import com.exasol.datatype.type.DataType;
 import com.exasol.sql.expression.ValueExpression;
 import com.exasol.sql.expression.ValueExpressionVisitor;
 import com.exasol.sql.expression.function.AbstractFunction;
@@ -14,7 +15,7 @@ public class ExasolFunction extends AbstractFunction {
     private static final List<String> functionsWithoutParenthesis = Arrays.asList("SYSDATE", "CURRENT_SCHEMA",
             "CURRENT_SESSION", "CURRENT_STATEMENT", "CURRENT_USER", "ROWNUM", "ROWID", "SCOPE_USER", "USER");
 
-    private ExasolFunction(final FunctionName functionName, final List<ValueExpression> valueExpressions) {
+    protected ExasolFunction(final FunctionName functionName, final List<ValueExpression> valueExpressions) {
         super(functionName.toString(), valueExpressions);
     }
 
@@ -31,14 +32,18 @@ public static ExasolFunction of(final FunctionName functionName) {
     /**
      * Create a new {@link ExasolFunction} instance.
      *
-     * @param functionName name of the function
+     * @param functionName     name of the function
      * @param valueExpressions zero or more value expressions
      * @return new {@link ExasolFunction}
      */
     public static ExasolFunction of(final FunctionName functionName, final ValueExpression... valueExpressions) {
         return new ExasolFunction(functionName, Arrays.asList(valueExpressions));
     }
 
+    public static ExasolFunction castScalarFunction(final ValueExpression valueExpression, final DataType dataType) {
+        return ExasolFunctionCast.of(valueExpression, dataType);
+    }
+
     @Override
     public boolean hasParenthesis() {
         return !functionsWithoutParenthesis.contains(this.functionName);

diff --git a/...n/function/exasol/ExasolCastFunction.java → ...n/function/exasol/ExasolFunctionCast.java b/...n/function/exasol/ExasolCastFunction.java → ...n/function/exasol/ExasolFunctionCast.java
@@ -5,29 +5,28 @@
 import com.exasol.datatype.type.DataType;
 import com.exasol.sql.expression.ValueExpression;
 import com.exasol.sql.expression.ValueExpressionVisitor;
-import com.exasol.sql.expression.function.AbstractFunction;
+import com.exasol.sql.expression.function.FunctionName;
 
 /**
  * This class represents the Exasol CAST function.
  */
-public class ExasolCastFunction extends AbstractFunction {
-    private static final String FUNCTION_NAME = "CAST";
+public class ExasolFunctionCast extends ExasolFunction {
     private final DataType type;
 
-    private ExasolCastFunction(final ValueExpression value, final DataType type) {
-        super(FUNCTION_NAME, List.of(value));
+    private ExasolFunctionCast(final ValueExpression value, final DataType type) {
+        super(ExasolScalarFunctionCast.CAST, List.of(value));
         this.type = type;
     }
 
     /**
-     * Create a new {@link ExasolCastFunction} instance.
+     * Create a new {@link ExasolFunctionCast} instance.
      *
      * @param valueExpression value to cast
      * @param type            type to cast the value to
-     * @return new {@link ExasolCastFunction}
+     * @return new {@link ExasolFunctionCast}
      */
-    public static ExasolCastFunction of(final ValueExpression valueExpression, final DataType type) {
-        return new ExasolCastFunction(valueExpression, type);
+    public static ExasolFunctionCast of(final ValueExpression valueExpression, final DataType type) {
+        return new ExasolFunctionCast(valueExpression, type);
     }
 
     /**
@@ -57,4 +56,8 @@ public boolean hasParenthesis() {
     public void accept(final ValueExpressionVisitor visitor) {
         visitor.visit(this);
     }
+
+    private enum ExasolScalarFunctionCast implements FunctionName {
+        CAST
+    }
 }
diff --git a/src/main/java/com/exasol/sql/expression/rendering/ValueExpressionRenderer.java b/src/main/java/com/exasol/sql/expression/rendering/ValueExpressionRenderer.java
@@ -5,9 +5,7 @@
 import com.exasol.sql.UnnamedPlaceholder;
 import com.exasol.sql.expression.*;
 import com.exasol.sql.expression.function.Function;
-import com.exasol.sql.expression.function.exasol.ExasolCastFunction;
-import com.exasol.sql.expression.function.exasol.ExasolFunction;
-import com.exasol.sql.expression.function.exasol.ExasolUdf;
+import com.exasol.sql.expression.function.exasol.*;
 import com.exasol.sql.rendering.ColumnsDefinitionRenderer;
 import com.exasol.sql.rendering.StringRendererConfig;
 
@@ -169,7 +167,7 @@ public void visit(final BooleanExpression booleanExpression) {
     }
 
     @Override
-    public void visit(final ExasolCastFunction castFunction) {
+    public void visit(final ExasolFunctionCast castFunction) {
         appendKeyword("CAST");
         startParenthesis();
         castFunction.getValue().accept(this);

diff --git a/src/test/java/com/exasol/sql/expression/function/exasol/ExasolAnalyticFunctionTest.java b/src/test/java/com/exasol/sql/expression/function/exasol/ExasolAnalyticFunctionTest.java
@@ -16,7 +16,7 @@ class ExasolAnalyticFunctionTest {
     void testAggregateFunctionCoalesce() {
         final Select select = StatementFactory.getInstance().select() //
                 .field("department") //
-                .function(ExasolAnalyticFunctions.ANY, " ANY_ ", BooleanTerm.lt(column("age"), integerLiteral(30)));
+                .function(ExasolAnalyticFunction.ANY, " ANY_ ", BooleanTerm.lt(column("age"), integerLiteral(30)));
         select.from().table("employee_table");
         select.groupBy(column("department"));
         assertThat(select,

diff --git a/...nction/exasol/ExasolCastFunctionTest.java → ...nction/exasol/ExasolFunctionCastTest.java b/...nction/exasol/ExasolCastFunctionTest.java → ...nction/exasol/ExasolFunctionCastTest.java
@@ -10,18 +10,18 @@
 import com.exasol.sql.dql.select.Select;
 import com.exasol.sql.expression.NullLiteral;
 
-class ExasolCastFunctionTest {
-
+class ExasolFunctionCastTest {
     @Test
     void testRendering() {
-        final Select select = StatementFactory.getInstance().select().cast(NullLiteral.nullLiteral(), new Varchar(254));
+        final Select select = StatementFactory.getInstance().select()
+                .function(ExasolFunction.castScalarFunction(NullLiteral.nullLiteral(), new Varchar(254)));
         assertThat(select, rendersTo("SELECT CAST(NULL AS VARCHAR(254))"));
     }
 
     @Test
     void testRenderingWithName() {
-        final Select select = StatementFactory.getInstance().select().cast(NullLiteral.nullLiteral(), new Varchar(254),
-                "TEST");
+        final Select select = StatementFactory.getInstance().select()
+                .function(ExasolFunction.castScalarFunction(NullLiteral.nullLiteral(), new Varchar(254)), "TEST");
         assertThat(select, rendersTo("SELECT CAST(NULL AS VARCHAR(254)) TEST"));
     }
 }