io.mindmaps.graql.internal.template.TemplateParser Maven / Gradle / Ivy

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/*
 * MindmapsDB - A Distributed Semantic Database
 * Copyright (C) 2016  Mindmaps Research Ltd
 *
 * MindmapsDB is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * MindmapsDB is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with MindmapsDB. If not, see .
 */

package io.mindmaps.graql.internal.template;

import io.mindmaps.graql.internal.antlr.GraqlTemplateLexer;
import io.mindmaps.graql.internal.antlr.GraqlTemplateParser;
import io.mindmaps.graql.internal.template.macro.DoubleMacro;
import io.mindmaps.graql.internal.template.macro.IntMacro;
import io.mindmaps.graql.internal.template.macro.Macro;
import io.mindmaps.graql.internal.template.macro.NoescpMacro;
import io.mindmaps.graql.internal.template.macro.EqualsMacro;
import org.antlr.v4.runtime.ANTLRInputStream;
import org.antlr.v4.runtime.CommonTokenStream;
import org.antlr.v4.runtime.tree.ParseTree;

import java.util.HashMap;
import java.util.Map;

public class TemplateParser {

    private static Map> macros;

    /**
     * Create a template parser
     */
    private TemplateParser(){
        registerDefaultMacros();
    }

    /**
     * Create a template parser
     * @return a template parser
     */
    public static TemplateParser create(){
        return new TemplateParser();
    }

    public void registerMacro(String name, Macro macro){
        macros.put(name, macro);
    }

    /**
     * Parse and resolve a graql template
     * @param templateString a string representing a graql template
     * @param data data to use in template
     * @return resolved graql query string
     */
    public String parseTemplate(String templateString, Map data){

        GraqlTemplateLexer lexer = getLexer(templateString);
        CommonTokenStream tokens = new CommonTokenStream(lexer);
        GraqlTemplateParser parser = getParser(tokens);
        parser.setBuildParseTree(true);
        ParseTree tree = parser.template();

        TemplateVisitor visitor = new TemplateVisitor(tokens, data, macros);
        return visitor.visit(tree).toString();
    }


    private GraqlTemplateLexer getLexer(String templateString){
        ANTLRInputStream inputStream = new ANTLRInputStream(templateString);
        return new GraqlTemplateLexer(inputStream);
    }

    private GraqlTemplateParser getParser(CommonTokenStream tokens){
        return new GraqlTemplateParser(tokens);
    }

    /**
     * Register the default macros that can be used by the visitor
     */
    private void registerDefaultMacros(){
        macros = new HashMap<>();
        registerMacro("noescp", new NoescpMacro());
        registerMacro("int", new IntMacro());
        registerMacro("double", new DoubleMacro());
        registerMacro("equals", new EqualsMacro());
    }
}