GwtXmlUtils.java

/*******************************************************************************
 * Copyright (c) 2012-2017 Codenvy, S.A.
 * 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:
 *   Codenvy, S.A. - initial API and implementation
 *******************************************************************************/
package org.eclipse.che.ide.commons;

import java.io.File;
import java.io.IOException;
import java.nio.file.FileSystems;
import java.nio.file.FileVisitOption;
import java.nio.file.FileVisitResult;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.PathMatcher;
import java.nio.file.SimpleFileVisitor;
import java.nio.file.attribute.BasicFileAttributes;
import java.util.EnumSet;
import java.util.List;

import static java.nio.charset.StandardCharsets.UTF_8;
import static java.nio.file.FileVisitResult.CONTINUE;
import static java.nio.file.FileVisitResult.TERMINATE;

/**
 * A smattering of useful methods to work with GWT module descriptor (*.gwt.xml) files.
 *
 * @author Artem Zatsarynnyi
 */
public class GwtXmlUtils {
    /** Filename suffix used for GWT module XML files. */
    public static final String GWT_MODULE_XML_SUFFIX = ".gwt.xml";

    private GwtXmlUtils() {
    }

    /**
     * Inherit the specified module name in the provided GWT module descriptor.
     *
     * @param path
     *         GWT module descriptor
     * @param inheritableModuleLogicalName
     *         logical name of the GWT module to inherit
     * @throws java.io.IOException
     *         error occurred while reading or writing content of file
     */
    public static void inheritGwtModule(Path path, String inheritableModuleLogicalName) throws IOException {
        final String inheritsString = "    <inherits name='" + inheritableModuleLogicalName + "'/>";
        List<String> content = Files.readAllLines(path, UTF_8);
        // insert custom module as last 'inherits' entry
        int i = 0, lastInheritsLine = 0;
        for (String str : content) {
            i++;
            if (str.contains("<inherits")) {
                lastInheritsLine = i;
            }
        }
        content.add(lastInheritsLine, inheritsString);
        Files.write(path, content, UTF_8);
    }

    /**
     * Returns logical name of the first found GWT module.
     *
     * @param folder
     *         path to folder that contains project sources
     * @return GWT module logical name
     * @throws java.io.IOException
     *         if an I/O error is thrown while finding GWT module descriptor
     * @throws IllegalArgumentException
     *         if GWT module descriptor not found
     */
    public static String detectGwtModuleLogicalName(Path folder) throws IOException {
        final String resourcesDir = folder.toString();

        Finder finder = new Finder("*" + GWT_MODULE_XML_SUFFIX);
        Files.walkFileTree(folder, EnumSet.of(FileVisitOption.FOLLOW_LINKS), Integer.MAX_VALUE, finder);
        if (finder.getFirstMatchedFile() == null) {
            throw new IllegalArgumentException("GWT module descriptor (*.gwt.xml) not found.");
        }

        String filePath = finder.getFirstMatchedFile().toString();
        filePath = filePath.substring(filePath.indexOf(resourcesDir) + resourcesDir.length() + 1,
                                      filePath.length() - GWT_MODULE_XML_SUFFIX.length());
        return filePath.replace(File.separatorChar, '.');
    }

    /** A {@code FileVisitor} that finds first file that match the specified pattern. */
    private static class Finder extends SimpleFileVisitor<Path> {
        final PathMatcher matcher;
        Path firstMatchedFile;

        Finder(String pattern) {
            matcher = FileSystems.getDefault().getPathMatcher("glob:" + pattern);
        }

        /** {@inheritDoc} */
        @Override
        public FileVisitResult visitFile(Path file, BasicFileAttributes attrs) throws IOException {
            Path fileName = file.getFileName();
            if (fileName != null && matcher.matches(fileName)) {
                firstMatchedFile = file;
                return TERMINATE;
            }
            return CONTINUE;
        }

        /** Returns the first matched {@link java.nio.file.Path}. */
        Path getFirstMatchedFile() {
            return firstMatchedFile;
        }
    }
}