SQL: Add support for single parameter text manipulating functions (#31874)

Added support for ASCII, BIT_LENGTH, CHAR, CHAR_LENGTH, LCASE, LENGTH, LTRIM, RTRIM, SPACE, UCASE functions.
Wherever Painless scripting is necessary (WHERE conditions, ORDER BY etc), those scripts are being used.

Author: astefan

x-pack/plugin/sql/src/main/java/org/elasticsearch/xpack/sql/expression/function/FunctionRegistry.java

@@ -58,6 +58,16 @@
 import org.elasticsearch.xpack.sql.expression.function.scalar.math.Sinh;
 import org.elasticsearch.xpack.sql.expression.function.scalar.math.Sqrt;
 import org.elasticsearch.xpack.sql.expression.function.scalar.math.Tan;
+import org.elasticsearch.xpack.sql.expression.function.scalar.string.Ascii;
+import org.elasticsearch.xpack.sql.expression.function.scalar.string.BitLength;
+import org.elasticsearch.xpack.sql.expression.function.scalar.string.Char;
+import org.elasticsearch.xpack.sql.expression.function.scalar.string.CharLength;
+import org.elasticsearch.xpack.sql.expression.function.scalar.string.LCase;
+import org.elasticsearch.xpack.sql.expression.function.scalar.string.LTrim;
+import org.elasticsearch.xpack.sql.expression.function.scalar.string.Length;
+import org.elasticsearch.xpack.sql.expression.function.scalar.string.RTrim;
+import org.elasticsearch.xpack.sql.expression.function.scalar.string.Space;
+import org.elasticsearch.xpack.sql.expression.function.scalar.string.UCase;
 import org.elasticsearch.xpack.sql.parser.ParsingException;
 import org.elasticsearch.xpack.sql.tree.Location;
 import org.elasticsearch.xpack.sql.util.StringUtils;
@@ -134,6 +144,17 @@ public class FunctionRegistry {
             def(Sinh.class, Sinh::new),
             def(Sqrt.class, Sqrt::new),
             def(Tan.class, Tan::new),
+            // String
+            def(Ascii.class, Ascii::new),
+            def(Char.class, Char::new),
+            def(BitLength.class, BitLength::new),
+            def(CharLength.class, CharLength::new),
+            def(LCase.class, LCase::new),
+            def(Length.class, Length::new),
+            def(LTrim.class, LTrim::new),
+            def(RTrim.class, RTrim::new),
+            def(Space.class, Space::new),
+            def(UCase.class, UCase::new),
         // Special
             def(Score.class, Score::new)));
 
@@ -299,6 +320,7 @@ interface BinaryFunctionBuilder<T> {
         T build(Location location, Expression lhs, Expression rhs);
     }
 
+    @SuppressWarnings("overloads")
     private static FunctionDefinition def(Class<? extends Function> function, FunctionBuilder builder,
             boolean datetime, String... aliases) {
         String primaryName = normalize(function.getSimpleName());

x-pack/plugin/sql/src/main/java/org/elasticsearch/xpack/sql/expression/function/scalar/Processors.java

@@ -17,6 +17,7 @@
 import org.elasticsearch.xpack.sql.expression.function.scalar.processor.runtime.ConstantProcessor;
 import org.elasticsearch.xpack.sql.expression.function.scalar.processor.runtime.HitExtractorProcessor;
 import org.elasticsearch.xpack.sql.expression.function.scalar.processor.runtime.Processor;
+import org.elasticsearch.xpack.sql.expression.function.scalar.string.StringProcessor;
 
 import java.util.ArrayList;
 import java.util.List;
@@ -46,6 +47,8 @@ public static List<NamedWriteableRegistry.Entry> getNamedWriteables() {
         entries.add(new Entry(Processor.class, DateTimeProcessor.NAME, DateTimeProcessor::new));
         // math
         entries.add(new Entry(Processor.class, MathProcessor.NAME, MathProcessor::new));
+        // string
+        entries.add(new Entry(Processor.class, StringProcessor.NAME, StringProcessor::new));
         return entries;
     }
 }

x-pack/plugin/sql/src/main/java/org/elasticsearch/xpack/sql/expression/function/scalar/math/ATan2.java

@@ -30,7 +30,7 @@ protected BiFunction<Number, Number, Number> operation() {
     }
 
     @Override
-    protected NodeInfo<? extends Expression> info() {
+    protected NodeInfo<ATan2> info() {
         return NodeInfo.create(this, ATan2::new, left(), right());
     }
 

x-pack/plugin/sql/src/main/java/org/elasticsearch/xpack/sql/expression/function/scalar/math/Power.java

@@ -26,7 +26,7 @@ protected BiFunction<Number, Number, Number> operation() {
     }
 
     @Override
-    protected NodeInfo<? extends Expression> info() {
+    protected NodeInfo<Power> info() {
         return NodeInfo.create(this, Power::new, left(), right());
     }
 

x-pack/plugin/sql/src/main/java/org/elasticsearch/xpack/sql/expression/function/scalar/string/Ascii.java

@@ -0,0 +1,42 @@
+/*
+ * 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.sql.expression.function.scalar.string;
+
+import org.elasticsearch.xpack.sql.expression.Expression;
+import org.elasticsearch.xpack.sql.expression.function.scalar.string.StringProcessor.StringOperation;
+import org.elasticsearch.xpack.sql.tree.Location;
+import org.elasticsearch.xpack.sql.tree.NodeInfo;
+import org.elasticsearch.xpack.sql.type.DataType;
+
+/**
+ * Returns the ASCII code of the leftmost character of the given (char) expression.
+ */
+public class Ascii extends UnaryStringFunction {
+
+    public Ascii(Location location, Expression field) {
+        super(location, field);
+    }
+
+    @Override
+    protected NodeInfo<Ascii> info() {
+        return NodeInfo.create(this, Ascii::new, field());
+    }
+
+    @Override
+    protected Ascii replaceChild(Expression newChild) {
+        return new Ascii(location(), newChild);
+    }
+
+    @Override
+    protected StringOperation operation() {
+        return StringOperation.ASCII;
+    }
+
+    @Override
+    public DataType dataType() {
+        return DataType.INTEGER;
+    }
+}

x-pack/plugin/sql/src/main/java/org/elasticsearch/xpack/sql/expression/function/scalar/string/BitLength.java

@@ -0,0 +1,43 @@
+/*
+ * 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.sql.expression.function.scalar.string;
+
+import org.elasticsearch.xpack.sql.expression.Expression;
+import org.elasticsearch.xpack.sql.expression.function.scalar.string.StringProcessor.StringOperation;
+import org.elasticsearch.xpack.sql.tree.Location;
+import org.elasticsearch.xpack.sql.tree.NodeInfo;
+import org.elasticsearch.xpack.sql.type.DataType;
+
+/**
+ * Returns returns the number of bits contained within the value expression.
+ */
+public class BitLength extends UnaryStringFunction {
+
+    public BitLength(Location location, Expression field) {
+        super(location, field);
+    }
+
+    @Override
+    protected NodeInfo<BitLength> info() {
+        return NodeInfo.create(this, BitLength::new, field());
+    }
+
+    @Override
+    protected BitLength replaceChild(Expression newChild) {
+        return new BitLength(location(), newChild);
+    }
+
+    @Override
+    protected StringOperation operation() {
+        return StringOperation.BIT_LENGTH;
+    }
+
+    @Override
+    public DataType dataType() {
+        //TODO investigate if a data type Long (BIGINT) wouldn't be more appropriate here
+        return DataType.INTEGER;
+    }
+}

x-pack/plugin/sql/src/main/java/org/elasticsearch/xpack/sql/expression/function/scalar/string/Char.java

@@ -0,0 +1,42 @@
+/*
+ * 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.sql.expression.function.scalar.string;
+
+import org.elasticsearch.xpack.sql.expression.Expression;
+import org.elasticsearch.xpack.sql.expression.function.scalar.string.StringProcessor.StringOperation;
+import org.elasticsearch.xpack.sql.tree.Location;
+import org.elasticsearch.xpack.sql.tree.NodeInfo;
+import org.elasticsearch.xpack.sql.type.DataType;
+
+/**
+ * Converts an int ASCII code to a character value.
+ */
+public class Char extends UnaryStringIntFunction {
+
+    public Char(Location location, Expression field) {
+        super(location, field);
+    }
+
+    @Override
+    protected NodeInfo<Char> info() {
+        return NodeInfo.create(this, Char::new, field());
+    }
+
+    @Override
+    protected Char replaceChild(Expression newChild) {
+        return new Char(location(), newChild);
+    }
+
+    @Override
+    protected StringOperation operation() {
+        return StringOperation.CHAR;
+    }
+
+    @Override
+    public DataType dataType() {
+        return DataType.KEYWORD;
+    }
+}

x-pack/plugin/sql/src/main/java/org/elasticsearch/xpack/sql/expression/function/scalar/string/CharLength.java

@@ -0,0 +1,42 @@
+/*
+ * 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.sql.expression.function.scalar.string;
+
+import org.elasticsearch.xpack.sql.expression.Expression;
+import org.elasticsearch.xpack.sql.expression.function.scalar.string.StringProcessor.StringOperation;
+import org.elasticsearch.xpack.sql.tree.Location;
+import org.elasticsearch.xpack.sql.tree.NodeInfo;
+import org.elasticsearch.xpack.sql.type.DataType;
+
+/**
+ * Returns the length (in characters) of the string expression.
+ */
+public class CharLength extends UnaryStringFunction {
+
+    public CharLength(Location location, Expression field) {
+        super(location, field);
+    }
+
+    @Override
+    protected NodeInfo<CharLength> info() {
+        return NodeInfo.create(this, CharLength::new, field());
+    }
+
+    @Override
+    protected CharLength replaceChild(Expression newChild) {
+        return new CharLength(location(), newChild);
+    }
+
+    @Override
+    protected StringOperation operation() {
+        return StringOperation.CHAR_LENGTH;
+    }
+
+    @Override
+    public DataType dataType() {
+        return DataType.INTEGER;
+    }
+}

x-pack/plugin/sql/src/main/java/org/elasticsearch/xpack/sql/expression/function/scalar/string/LCase.java

@@ -0,0 +1,42 @@
+/*
+ * 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.sql.expression.function.scalar.string;
+
+import org.elasticsearch.xpack.sql.expression.Expression;
+import org.elasticsearch.xpack.sql.expression.function.scalar.string.StringProcessor.StringOperation;
+import org.elasticsearch.xpack.sql.tree.Location;
+import org.elasticsearch.xpack.sql.tree.NodeInfo;
+import org.elasticsearch.xpack.sql.type.DataType;
+
+/**
+ * Lowercases all uppercase letters in a string.
+ */
+public class LCase extends UnaryStringFunction {
+
+    public LCase(Location location, Expression field) {
+        super(location, field);
+    }
+
+    @Override
+    protected NodeInfo<LCase> info() {
+        return NodeInfo.create(this, LCase::new, field());
+    }
+
+    @Override
+    protected LCase replaceChild(Expression newChild) {
+        return new LCase(location(), newChild);
+    }
+
+    @Override
+    protected StringOperation operation() {
+        return StringOperation.LCASE;
+    }
+
+    @Override
+    public DataType dataType() {
+        return DataType.KEYWORD;
+    }
+}

x-pack/plugin/sql/src/main/java/org/elasticsearch/xpack/sql/expression/function/scalar/string/LTrim.java

@@ -0,0 +1,43 @@
+/*
+ * 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.sql.expression.function.scalar.string;
+
+import org.elasticsearch.xpack.sql.expression.Expression;
+import org.elasticsearch.xpack.sql.expression.function.scalar.string.StringProcessor.StringOperation;
+import org.elasticsearch.xpack.sql.tree.Location;
+import org.elasticsearch.xpack.sql.tree.NodeInfo;
+import org.elasticsearch.xpack.sql.type.DataType;
+
+/**
+ * Trims the leading whitespaces.
+ */
+public class LTrim extends UnaryStringFunction {
+
+    public LTrim(Location location, Expression field) {
+        super(location, field);
+    }
+
+    @Override
+    protected NodeInfo<LTrim> info() {
+        return NodeInfo.create(this, LTrim::new, field());
+    }
+
+    @Override
+    protected LTrim replaceChild(Expression newChild) {
+        return new LTrim(location(), newChild);
+    }
+
+    @Override
+    protected StringOperation operation() {
+        return StringOperation.LTRIM;
+    }
+
+    @Override
+    public DataType dataType() {
+        return DataType.KEYWORD;
+    }
+
+}