eu.numberfour.n4js.antlr.replacements.Replacements.java Source code

Introduction

Here is the source code for eu.numberfour.n4js.antlr.replacements.Replacements.java

Source

/**
 * Copyright (c) 2016 NumberFour AG.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *   NumberFour AG - Initial API and implementation
 */
package eu.numberfour.n4js.antlr.replacements;

import java.io.IOException;
import java.net.URL;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import com.google.common.base.Charsets;
import com.google.common.io.Resources;

/**
 * Replacement methods used by injectors to replace snippets in the generated grammar and lexer, and by fragments to
 * replace snippets in the generated java parser.
 */
public class Replacements {

    /**
     * Returns the simple name of the top level class defined in the given grammar content.
     */
    public static String getGrammarClass(String grammarContent) {
        Matcher m = Pattern.compile("public\\ class\\ ([a-zA-Z0-9_]+)\\ ").matcher(grammarContent);
        if (m.find()) {
            return m.group(1);
        }
        return "unknown grammar class";
    }

    /**
     * Replaces all matches of the given pattern in the given input string. If no match was found, an
     * {@link IllegalStateException} is raised.
     *
     * @see String#replaceAll(String, String)
     */
    public static String replaceAll(String in, String pattern, String replacement) {
        String result = in.replaceAll(pattern, replacement);
        if (result.equals(in)) {
            Thread.dumpStack();
            throw new IllegalStateException("Did not find '" + pattern + "' in grammar");
        }
        return result;
    }

    /**
     * Replaces all matches of the given pattern in the given input string. If no match was found, an
     * {@link IllegalStateException} is raised.
     *
     * @see String#replaceFirst(String, String)
     */
    public static String replaceFirst(String in, String pattern, String replacement) {
        String result = in.replaceFirst(pattern, replacement);
        if (result.equals(in)) {
            Thread.dumpStack();
            throw new IllegalStateException("Did not find '" + pattern + "' in grammar");
        }
        return result;
    }

    /**
     * Replaces all matches of the given lookup in the given input string. If no match was found, an
     * {@link IllegalStateException} is raised.
     *
     * @see String#replace(CharSequence, CharSequence)
     */
    public static String replace(String in, String lookup, String replacement) {
        String result = in.replace(lookup, replacement);
        if (result.equals(in)) {
            Thread.dumpStack();
            throw new IllegalStateException("Did not find '" + lookup + "' in grammar");
        }
        return result;
    }

    /**
     * Applies a replacement, which is a string containing both the lookup (non-regex) and the replacement.These two
     * strings are separated via
     *
     * <pre>
     * _________________________________REPLACE_WITH_________________________________
     * </pre>
     *
     * The replacement file has to be in the same folder as this class.
     */
    public static String applyReplacement(String in, String replacementName) {
        try {
            URL url = ClassLoader.getSystemResource(
                    Replacements.class.getPackage().getName().replace(".", "/") + "/" + replacementName);
            // normalize string to run on Windows and Mac/Unix
            String replacement = Resources.toString(url, Charsets.UTF_8).replace("\r\n", "\n");

            String[] findReplace = replacement
                    .split("\n_________________________________REPLACE_WITH_________________________________\n");

            return replace(in, findReplace[0], findReplace[1]);
        } catch (IOException e) {
            throw new IllegalStateException(e);
        }
    }

}