change pom to java11 and add visitor + examples

CONTRIBUTING.md

@@ -0,0 +1,6 @@
+1. Make sure you have Java 11 installed by running `java -v`
+2. Clone the repo
+3. In root, run `mvn clean install`
+4. Set up Google style. To do this in IntelliJ, follow this guide: https://medium.com/swlh/configuring-google-style-guide-for-java-for-intellij-c727af4ef248
+5. In IntelliJ, you may need to go to each module, click on src folder, mark directory as -> sources root.
+This will let you run IntelliJ

common/pom.xml

@@ -1,4 +1,5 @@
-<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
   xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
   <modelVersion>4.0.0</modelVersion>
 

common/src/README.md

@@ -1 +1,2 @@
-Common resources for other packages. To prevent circular dependencies, avoid adding dependencies on other packages to common.
+Common resources for other packages. To prevent circular dependencies, avoid adding dependencies on
+other packages to common.

common/src/logical_node/Node.java

@@ -0,0 +1,12 @@
+package logical_node;
+
+import java.util.List;
+
+public abstract class Node {
+
+  public <R, C> R accept(Visitor<R, C> visitor, C context) {
+    return visitor.visitPlan(this, context);
+  }
+
+  List<Node> children;
+}

common/src/logical_node/Visitor.java

@@ -0,0 +1,13 @@
+package logical_node;
+
+// Visitor interface needs to be aware of all implementations of Node to have visit{x}Node methods declared for each.
+public abstract class Visitor<R, C> {
+
+  abstract R visitPlan(Node node, C context);
+
+  // Example visit node function. See examples directory for complete example of implemented visitor pattern.
+//    R visitDogNode(DogNode node, C context) {
+//        return visitPlan(node, context);
+//    }
+
+}

common/src/logical_node/examples/AnimalNode.java

@@ -0,0 +1,12 @@
+package logical_node.examples;
+
+import java.util.List;
+
+public abstract class AnimalNode {
+
+  public <R, C> R accept(AnimalVisitor<R, C> visitor, C context) {
+    return visitor.visitPlan(this, context);
+  }
+
+  List<AnimalNode> children;
+}

common/src/logical_node/examples/AnimalVisitor.java

@@ -0,0 +1,15 @@
+package logical_node.examples;
+
+// Visitor interface needs to be aware of all implementations of Node to have visit{x}Node methods declared for each.
+public abstract class AnimalVisitor<R, C> {
+
+  abstract R visitPlan(AnimalNode node, C context);
+
+  R visitDogNode(DogNode node, C context) {
+    return visitPlan(node, context);
+  }
+
+  R visitCatNode(CatNode node, C context) {
+    return visitPlan(node, context);
+  }
+}

common/src/logical_node/examples/CatNode.java

@@ -0,0 +1,23 @@
+package logical_node.examples;
+
+public class CatNode extends AnimalNode {
+
+  @Override
+  public <R, C> R accept(AnimalVisitor<R, C> visitor, C context) {
+    return visitor.visitCatNode(this, context);
+  }
+
+  public CatNode(String id) {
+    this.children = null;
+    this.id = id;
+  }
+
+  @Override
+  public String toString() {
+    return "logical_node.examples.CatNode{" +
+        "id='" + id + '\'' +
+        '}';
+  }
+
+  String id;
+}

common/src/logical_node/examples/DogNode.java

@@ -0,0 +1,25 @@
+package logical_node.examples;
+
+import java.util.List;
+
+public class DogNode extends AnimalNode {
+
+  @Override
+  public <R, C> R accept(AnimalVisitor<R, C> visitor, C context) {
+    return visitor.visitDogNode(this, context);
+  }
+
+  public DogNode(String id, List<AnimalNode> children) {
+    this.children = children;
+    this.id = id;
+  }
+
+  @Override
+  public String toString() {
+    return "logical_node.examples.DogNode{" +
+        "id='" + id + '\'' +
+        '}';
+  }
+
+  String id;
+}

common/src/logical_node/examples/Main.java

@@ -0,0 +1,26 @@
+package logical_node.examples;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class Main {
+
+  static AnimalNode createDogTree() {
+    DogNode dog1 = new DogNode("Leaf doggo", new ArrayList<>());
+    CatNode cat1 = new CatNode("Leaf kitty1");
+    CatNode cat2 = new CatNode("Leaf kitty2");
+    DogNode dog2 = new DogNode("Intermediate doggo", List.of(cat1, dog1));
+    DogNode dog3 = new DogNode("Root doggo", List.of(dog2, cat2));
+
+    return dog3;
+  }
+
+  public static void main(String[] args) {
+    AnimalNode node = createDogTree();
+
+    PrettyPrintVisitor visitor = new PrettyPrintVisitor();
+
+    // Enter plan on unknown node type
+    visitor.visitPlan(node, "");
+  }
+}

common/src/logical_node/examples/PrettyPrintVisitor.java

@@ -0,0 +1,27 @@
+package logical_node.examples;
+
+public class PrettyPrintVisitor extends AnimalVisitor<Void, String> {
+
+  @Override
+  Void visitPlan(AnimalNode node, String context) {
+    node.accept(this, context);
+    return null;
+  }
+
+  @Override
+  Void visitDogNode(DogNode node, String context) {
+    // Print it's a good boy
+    System.out.println(context + node.toString());
+    // Enter children
+    for (AnimalNode n : node.children) {
+      visitPlan(n, context + "  ");
+    }
+    return null;
+  }
+
+  @Override
+  Void visitCatNode(CatNode node, String context) {
+    System.out.println(context + node.toString());
+    return null;
+  }
+}

common/src/logical_node/examples/README.md

@@ -0,0 +1,4 @@
+Example of how to implement a visitor.
+
+-- todo(jason) -> Put down our learnings as bullet points here- explain what a visitor does,
+how to implement one for a specific type of node, how to add a new visitor/node

common/src/types/Type.java

@@ -4,8 +4,7 @@
  * Types must map
  */
 public enum Type {
-    INT,
-    VARCHAR,
-    BOOL
+  INT,
+  VARCHAR,
+  BOOL
 }
-

execution/pom.xml

@@ -1,4 +1,5 @@
-<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
   xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
   <modelVersion>4.0.0</modelVersion>
 

main/pom.xml

@@ -1,4 +1,5 @@
-<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
   xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
   <modelVersion>4.0.0</modelVersion>
 

main/src/Main.java

@@ -1,6 +1,3 @@
 public class Main {
 
-  public static void main(String[] args) {
-    System.out.println("Hello world!");
-  }
-}
+}

parser/pom.xml

@@ -1,6 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
 
-<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
   xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
   <modelVersion>4.0.0</modelVersion>
 

parser/src/README.md

@@ -1,6 +1,8 @@
 Parser layer does this:
 
-
-- Tokenize the input SQL statement. `SELECT (c1, c3) FROM tbl` should be converted to `[select,(,c1,c3,),FROM,tbl`
-- Turn tokenized input into an AST. Then on the AST, do some language-level optimizations: CSE, const folding (use visitor pattern)
-- Turn AST into IR. Maybe this should be a different layer? Anyways, figure out the difference, if there is one, between IR and the nodes we perform logical optimizations on
+- Tokenize the input SQL statement. `SELECT (c1, c3) FROM tbl` should be converted
+  to `[select,(,c1,c3,),FROM,tbl`
+- Turn tokenized input into an AST. Then on the AST, do some language-level optimizations: CSE,
+  const folding (use visitor pattern)
+- Turn AST into IR. Maybe this should be a different layer? Anyways, figure out the difference, if
+  there is one, between IR and the nodes we perform logical optimizations on

parser/src/main/antlr4/org/mycompany/README.md

@@ -1,3 +1,5 @@
-- SqlBase is a copy of Presto's grammar file. It was not apparent to me how to initialize all the available grammars
-- SqlGrammarCopy is a direct copy from https://medium.com/@sasidharc/build-sql-parser-using-antlr4-part1-2044916a8406
+- SqlBase is a copy of Presto's grammar file. It was not apparent to me how to initialize all the
+  available grammars
+- SqlGrammarCopy is a direct copy
+  from https://medium.com/@sasidharc/build-sql-parser-using-antlr4-part1-2044916a8406
 - SqlGrammar is the above, but edited. Use this as a sandbox.

parser/src/main/java.org.mycompany/Main.java

@@ -86,6 +86,7 @@ public void exitConstants(ConstantsContext ctx) {
     @Override
     public void enterExpressionList(ExpressionListContext ctx) {
     }
+
     @Override
     public void exitExpressionList(ExpressionListContext ctx) {
 
@@ -122,7 +123,7 @@ public void exitExpression(ExpressionContext ctx) {
 
     @Override
     public void enterIdentifier(IdentifierContext ctx) {
-      int size =  ctx.IDENTIFIER().size();
+      int size = ctx.IDENTIFIER().size();
       if (size == 2) {
         // Qualified with table name
       } else if (size == 1) {
@@ -183,6 +184,7 @@ public void exitEveryRule(ParserRuleContext parserRuleContext) {
 
     }
   }
+
   public static void main(String[] args) throws IOException {
 
     // This works in lexer/parser, but not lexer/parser{2} (presto grammar). Cookie for who
@@ -192,11 +194,11 @@ public static void main(String[] args) throws IOException {
     // create a CharStream that reads from standard input
     ANTLRInputStream input = new ANTLRInputStream(inputString);
 
-        // create a lexer that feeds off of input CharStream
+    // create a lexer that feeds off of input CharStream
     SqlGrammarLexer lexer = new SqlGrammarLexer(input);
 
     // create a buffer of tokens pulled from the lexer
-        CommonTokenStream tokens = new CommonTokenStream(lexer);
+    CommonTokenStream tokens = new CommonTokenStream(lexer);
 
     // create a parser that feeds off the tokens buffer
     SqlGrammarParser parser = new SqlGrammarParser(tokens);
@@ -208,7 +210,7 @@ public static void main(String[] args) throws IOException {
     SqlGrammarListener listener = new MyListener();
     walker.walk(listener, tree);
 
-        System.out.println(tree.toStringTree(parser)); // print LISP-style tree
+    System.out.println(tree.toStringTree(parser)); // print LISP-style tree
 
   }
 }

planner/pom.xml

@@ -1,4 +1,5 @@
-<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
   xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
   <modelVersion>4.0.0</modelVersion>
 

planner/src/Main.java

@@ -1,5 +1,6 @@
 public class Main {
-    public static void main(String[] args) {
-        System.out.println("Hello world!");
-    }
+
+  public static void main(String[] args) {
+    System.out.println("Hello world!");
+  }
 }