io.proleap.cobol.preprocessor.sub.parser.impl.CobolParserPreprocessorImpl.java Source code

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Here is the source code for io.proleap.cobol.preprocessor.sub.parser.impl.CobolParserPreprocessorImpl.java

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/*
 * Copyright (C) 2017, Ulrich Wolffgang <u.wol@wwu.de>
 * All rights reserved.
 *
 * This software may be modified and distributed under the terms
 * of the BSD 3-clause license. See the LICENSE file for details.
 */

package io.proleap.cobol.preprocessor.sub.parser.impl;

import java.io.File;

import org.antlr.v4.runtime.CharStreams;
import org.antlr.v4.runtime.CommonTokenStream;
import org.antlr.v4.runtime.tree.ParseTreeWalker;

import io.proleap.cobol.Cobol85PreprocessorLexer;
import io.proleap.cobol.Cobol85PreprocessorParser;
import io.proleap.cobol.Cobol85PreprocessorParser.StartRuleContext;
import io.proleap.cobol.preprocessor.CobolPreprocessor.CobolDialect;
import io.proleap.cobol.preprocessor.CobolPreprocessor.CobolSourceFormatEnum;
import io.proleap.cobol.preprocessor.sub.impl.ThrowingErrorListener;
import io.proleap.cobol.preprocessor.sub.parser.CobolParserPreprocessor;

/**
 * Preprocessor, which parses and processes COPY REPLACE and EXEC SQL
 * statements.
 */
public class CobolParserPreprocessorImpl implements CobolParserPreprocessor {

    protected final File libDirectory;

    protected final String[] triggers = new String[] { "copy", "exec sql", "exec sqlims", "exec cics", "replace" };

    public CobolParserPreprocessorImpl(final File libDirectory) {
        this.libDirectory = libDirectory;
    }

    protected boolean containsTrigger(final String line, final String[] triggers) {
        final String lineLowerCase = line.toLowerCase();
        boolean result = false;

        for (final String trigger : triggers) {
            final boolean containsTrigger = lineLowerCase.contains(trigger);

            if (containsTrigger) {
                result = true;
                break;
            }
        }

        return result;
    }

    @Override
    public String processLines(final String lines, final CobolSourceFormatEnum format, final CobolDialect dialect) {
        final boolean requiresProcessorExecution = containsTrigger(lines, triggers);
        final String result;

        if (requiresProcessorExecution) {
            result = processWithParser(lines, libDirectory, format, dialect);
        } else {
            result = lines;
        }

        return result;
    }

    protected String processWithParser(final String program, final File libDirectory,
            final CobolSourceFormatEnum format, final CobolDialect dialect) {
        // run the lexer
        final Cobol85PreprocessorLexer lexer = new Cobol85PreprocessorLexer(CharStreams.fromString(program));

        // get a list of matched tokens
        final CommonTokenStream tokens = new CommonTokenStream(lexer);

        // pass the tokens to the parser
        final Cobol85PreprocessorParser parser = new Cobol85PreprocessorParser(tokens);

        // register an error listener, so that preprocessing stops on errors
        parser.removeErrorListeners();
        parser.addErrorListener(new ThrowingErrorListener());

        // specify our entry point
        final StartRuleContext startRule = parser.startRule();

        // analyze contained copy books
        final CobolParserPreprocessorListenerImpl listener = new CobolParserPreprocessorListenerImpl(libDirectory,
                format, dialect, tokens);
        final ParseTreeWalker walker = new ParseTreeWalker();

        walker.walk(listener, startRule);

        final String result = listener.context().read();
        return result;
    }
}