io.cdap.wrangler.parser

Class RecipeVisitor

java.lang.Object

org.antlr.v4.runtime.tree.AbstractParseTreeVisitor<T>

io.cdap.wrangler.parser.DirectivesBaseVisitor<RecipeSymbol.Builder>

io.cdap.wrangler.parser.RecipeVisitor

All Implemented Interfaces:

DirectivesVisitor<RecipeSymbol.Builder>, org.antlr.v4.runtime.tree.ParseTreeVisitor<RecipeSymbol.Builder>

public final class RecipeVisitor
extends DirectivesBaseVisitor<RecipeSymbol.Builder>

This class RecipeVisitor implements the visitor pattern used during traversal of the AST tree. The ParserTree#Walker invokes appropriate methods as call backs with information about the node.

In order to understand what's being invoked, please look at the grammar file Directive.g4

.

This class exposes a getTokenGroups method for retrieving the RecipeSymbol after visiting. The RecipeSymbol represents all the TokenGroup for all directives in a recipe. Each directive will create a TokenGroup

As the ParseTree is walking through the call graph, it generates one TokenGroup for each directive in the recipe. Each TokenGroup contains parsed Tokens for that directive along with more information like SourceInfo. A collection of TokenGroup consistutes a RecipeSymbol that is returned by this function.

Constructor Summary

Constructors

Constructor and Description
RecipeVisitor()

Method Summary

Modifier and Type	Method and Description
RecipeSymbol	getCompiledUnit() Returns a RecipeSymbol for the recipe being parsed.
RecipeSymbol.Builder	visitBool(DirectivesParser.BoolContext ctx) A Directive can consist of Bool field.
RecipeSymbol.Builder	visitBoolList(DirectivesParser.BoolListContext ctx) This visitor methods extracts the list of booleans specified.
RecipeSymbol.Builder	visitColList(DirectivesParser.ColListContext ctx) This visitor methods extracts the list of columns specified.
RecipeSymbol.Builder	visitColumn(DirectivesParser.ColumnContext ctx) A Directive can consist of column specifiers.
RecipeSymbol.Builder	visitCommand(DirectivesParser.CommandContext ctx) A Directive has name and in the parsing context it's called a command.
RecipeSymbol.Builder	visitCondition(DirectivesParser.ConditionContext ctx) A Directive can include a expression or a condition to be evaluated.
RecipeSymbol.Builder	visitDirective(DirectivesParser.DirectiveContext ctx) A Recipe is made up of Directives and Directives is made up of each individual Directive.
RecipeSymbol.Builder	visitEcommand(DirectivesParser.EcommandContext ctx) This visitor method extracts the custom directive name specified.
RecipeSymbol.Builder	visitIdentifier(DirectivesParser.IdentifierContext ctx) A Directive can include identifiers, this method extracts that token that is being identified as token of type Identifier.
RecipeSymbol.Builder	visitNumber(DirectivesParser.NumberContext ctx) A Directive can consist of numeric field.
RecipeSymbol.Builder	visitNumberList(DirectivesParser.NumberListContext ctx) This visitor methods extracts the list of numeric specified.
RecipeSymbol.Builder	visitNumberRanges(DirectivesParser.NumberRangesContext ctx) A Directive can include number ranges like start:end=value[,start:end=value]*.
RecipeSymbol.Builder	visitPragmaLoadDirective(DirectivesParser.PragmaLoadDirectiveContext ctx) A Pragma is an instruction to the compiler to dynamically load the directives being specified from the DirectiveRegistry.
RecipeSymbol.Builder	visitPragmaVersion(DirectivesParser.PragmaVersionContext ctx) A Pragma version is a informational directive to notify compiler about the grammar that is should be using to parse the directives below.
RecipeSymbol.Builder	visitPropertyList(DirectivesParser.PropertyListContext ctx) A Directive can include properties (which are a collection of key and value pairs), this method extracts that token that is being identified as token of type Properties.
RecipeSymbol.Builder	visitStringList(DirectivesParser.StringListContext ctx) This visitor methods extracts the list of strings specified.
RecipeSymbol.Builder	visitText(DirectivesParser.TextContext ctx) A Directive can consist of text field.

Methods inherited from class io.cdap.wrangler.parser.DirectivesBaseVisitor

visitCodeblock, visitConfig, visitElseIfStat, visitElseStat, visitExpression, visitForStatement, visitIdentifierList, visitIfStat, visitIfStatement, visitMacro, visitNumberRange, visitPragma, visitProperties, visitProperty, visitRecipe, visitStatements, visitValue

Methods inherited from class org.antlr.v4.runtime.tree.AbstractParseTreeVisitor

aggregateResult, defaultResult, shouldVisitNextChild, visit, visitChildren, visitErrorNode, visitTerminal

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface org.antlr.v4.runtime.tree.ParseTreeVisitor

visit, visitChildren, visitErrorNode, visitTerminal

Constructor Detail

RecipeVisitor

public RecipeVisitor()

Method Detail

getCompiledUnit

public RecipeSymbol getCompiledUnit()

Returns a RecipeSymbol for the recipe being parsed. This object has all the tokens that were successfully parsed along with source information for each directive in the recipe.

Returns:

An compiled object after parsing the recipe.

visitDirective

public RecipeSymbol.Builder visitDirective(DirectivesParser.DirectiveContext ctx)

A Recipe is made up of Directives and Directives is made up of each individual Directive. This method is invoked on every visit to a new directive in the recipe.

Specified by:

visitDirective in interface DirectivesVisitor<RecipeSymbol.Builder>

Overrides:

visitDirective in class DirectivesBaseVisitor<RecipeSymbol.Builder>

Parameters:

ctx - the parse tree

Returns:

the visitor result

visitIdentifier

public RecipeSymbol.Builder visitIdentifier(DirectivesParser.IdentifierContext ctx)

A Directive can include identifiers, this method extracts that token that is being identified as token of type Identifier.

Specified by:

visitIdentifier in interface DirectivesVisitor<RecipeSymbol.Builder>

Overrides:

visitIdentifier in class DirectivesBaseVisitor<RecipeSymbol.Builder>

Parameters:

ctx - the parse tree

Returns:

the visitor result

visitPropertyList

public RecipeSymbol.Builder visitPropertyList(DirectivesParser.PropertyListContext ctx)

A Directive can include properties (which are a collection of key and value pairs), this method extracts that token that is being identified as token of type Properties.

Specified by:

visitPropertyList in interface DirectivesVisitor<RecipeSymbol.Builder>

Overrides:

visitPropertyList in class DirectivesBaseVisitor<RecipeSymbol.Builder>

Parameters:

ctx - the parse tree

Returns:

the visitor result

visitPragmaLoadDirective

public RecipeSymbol.Builder visitPragmaLoadDirective(DirectivesParser.PragmaLoadDirectiveContext ctx)

A Pragma is an instruction to the compiler to dynamically load the directives being specified from the DirectiveRegistry. These do not affect the data flow.

E.g. #pragma load-directives test1, test2, test3; will collect the tokens test1, test2 and test3 as dynamically loadable directives.

Specified by:

visitPragmaLoadDirective in interface DirectivesVisitor<RecipeSymbol.Builder>

Overrides:

visitPragmaLoadDirective in class DirectivesBaseVisitor<RecipeSymbol.Builder>

Parameters:

ctx - the parse tree

Returns:

the visitor result

visitPragmaVersion

public RecipeSymbol.Builder visitPragmaVersion(DirectivesParser.PragmaVersionContext ctx)

A Pragma version is a informational directive to notify compiler about the grammar that is should be using to parse the directives below.

Specified by:

visitPragmaVersion in interface DirectivesVisitor<RecipeSymbol.Builder>

Overrides:

visitPragmaVersion in class DirectivesBaseVisitor<RecipeSymbol.Builder>

Parameters:

ctx - the parse tree

Returns:

the visitor result

visitNumberRanges

public RecipeSymbol.Builder visitNumberRanges(DirectivesParser.NumberRangesContext ctx)

A Directive can include number ranges like start:end=value[,start:end=value]*. This visitor method allows you to collect all the number ranges and create a token type Ranges.

Specified by:

visitNumberRanges in interface DirectivesVisitor<RecipeSymbol.Builder>

Overrides:

visitNumberRanges in class DirectivesBaseVisitor<RecipeSymbol.Builder>

Parameters:

ctx - the parse tree

Returns:

the visitor result

visitEcommand

public RecipeSymbol.Builder visitEcommand(DirectivesParser.EcommandContext ctx)

This visitor method extracts the custom directive name specified. The custom directives are specified with a bang (!) at the start.

Specified by:

visitEcommand in interface DirectivesVisitor<RecipeSymbol.Builder>

Overrides:

visitEcommand in class DirectivesBaseVisitor<RecipeSymbol.Builder>

Parameters:

ctx - the parse tree

Returns:

the visitor result

visitColumn

public RecipeSymbol.Builder visitColumn(DirectivesParser.ColumnContext ctx)

A Directive can consist of column specifiers. These are columns that the directive would operate on. When a token of type column is visited, it would generate a token type of type ColumnName.

Specified by:

visitColumn in interface DirectivesVisitor<RecipeSymbol.Builder>

Overrides:

visitColumn in class DirectivesBaseVisitor<RecipeSymbol.Builder>

Parameters:

ctx - the parse tree

Returns:

the visitor result

visitText

public RecipeSymbol.Builder visitText(DirectivesParser.TextContext ctx)

A Directive can consist of text field. These type of fields are enclosed within a single-quote or a double-quote. This visitor method extracts the string value within the quotes and creates a token type Text.

Specified by:

visitText in interface DirectivesVisitor<RecipeSymbol.Builder>

Overrides:

visitText in class DirectivesBaseVisitor<RecipeSymbol.Builder>

Parameters:

ctx - the parse tree

Returns:

the visitor result

visitNumber

public RecipeSymbol.Builder visitNumber(DirectivesParser.NumberContext ctx)

A Directive can consist of numeric field. This visitor method extracts the numeric value Numeric.

Specified by:

visitNumber in interface DirectivesVisitor<RecipeSymbol.Builder>

Overrides:

visitNumber in class DirectivesBaseVisitor<RecipeSymbol.Builder>

Parameters:

ctx - the parse tree

Returns:

the visitor result

visitBool

public RecipeSymbol.Builder visitBool(DirectivesParser.BoolContext ctx)

A Directive can consist of Bool field. The Bool field is represented as either true or false. This visitor method extract the bool value into a token type Bool.

Specified by:

visitBool in interface DirectivesVisitor<RecipeSymbol.Builder>

Overrides:

visitBool in class DirectivesBaseVisitor<RecipeSymbol.Builder>

Parameters:

ctx - the parse tree

Returns:

the visitor result

visitCondition

public RecipeSymbol.Builder visitCondition(DirectivesParser.ConditionContext ctx)

A Directive can include a expression or a condition to be evaluated. When such a token type is found, the visitor extracts the expression and generates a token type Expression to be added to the TokenGroup

Specified by:

visitCondition in interface DirectivesVisitor<RecipeSymbol.Builder>

Overrides:

visitCondition in class DirectivesBaseVisitor<RecipeSymbol.Builder>

Parameters:

ctx - the parse tree

Returns:

the visitor result

visitCommand

public RecipeSymbol.Builder visitCommand(DirectivesParser.CommandContext ctx)

A Directive has name and in the parsing context it's called a command. This visitor methods extracts the command and creates a toke type DirectiveName

Specified by:

visitCommand in interface DirectivesVisitor<RecipeSymbol.Builder>

Overrides:

visitCommand in class DirectivesBaseVisitor<RecipeSymbol.Builder>

Parameters:

ctx - the parse tree

Returns:

the visitor result

visitColList

public RecipeSymbol.Builder visitColList(DirectivesParser.ColListContext ctx)

This visitor methods extracts the list of columns specified. It creates a token type ColumnNameList to be added to TokenGroup.

Specified by:

visitColList in interface DirectivesVisitor<RecipeSymbol.Builder>

Overrides:

visitColList in class DirectivesBaseVisitor<RecipeSymbol.Builder>

Parameters:

ctx - the parse tree

Returns:

the visitor result

visitNumberList

public RecipeSymbol.Builder visitNumberList(DirectivesParser.NumberListContext ctx)

This visitor methods extracts the list of numeric specified. It creates a token type NumericList to be added to TokenGroup.

Specified by:

visitNumberList in interface DirectivesVisitor<RecipeSymbol.Builder>

Overrides:

visitNumberList in class DirectivesBaseVisitor<RecipeSymbol.Builder>

Parameters:

ctx - the parse tree

Returns:

the visitor result

visitBoolList

public RecipeSymbol.Builder visitBoolList(DirectivesParser.BoolListContext ctx)

This visitor methods extracts the list of booleans specified. It creates a token type BoolList to be added to TokenGroup.

Specified by:

visitBoolList in interface DirectivesVisitor<RecipeSymbol.Builder>

Overrides:

visitBoolList in class DirectivesBaseVisitor<RecipeSymbol.Builder>

Parameters:

ctx - the parse tree

Returns:

the visitor result

visitStringList

public RecipeSymbol.Builder visitStringList(DirectivesParser.StringListContext ctx)

This visitor methods extracts the list of strings specified. It creates a token type StringList to be added to TokenGroup.

Specified by:

visitStringList in interface DirectivesVisitor<RecipeSymbol.Builder>

Overrides:

visitStringList in class DirectivesBaseVisitor<RecipeSymbol.Builder>

Parameters:

ctx - the parse tree

Returns:

the visitor result