com.ctriposs.rest4j.server.util.FileClassNameScanner.java Source code

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Here is the source code for com.ctriposs.rest4j.server.util.FileClassNameScanner.java

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/**
 * Copyright (C) 2014 the original author or authors.
 * See the notice.md file distributed with this work for additional
 * information regarding copyright ownership.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.ctriposs.rest4j.server.util;

import org.apache.commons.io.FileUtils;

import java.io.File;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.Map;

/**
 * Scanner to find class names under a directory according to their source file names.
 *
 */
public class FileClassNameScanner {
    /**
     * Construct map from fully qualified class name to filename whose sources are found under a given source directory.
     * All source files are required to have an extension. No specific extension is required.
     *
     * @param sourceDir the source directory to scan
     * @return map from fully qualified class name to filename for scanned source files.
     */
    public static Map<String, String> scan(String sourceDir) {
        return scan(sourceDir, null);
    }

    /**
     * Construct map from fully qualified class name to filename whose sources are found under a given source directory.
     * All source files are required to have an extension.
     *
     * @param sourceDir the source directory to scan
     * @param requiredExtension only include files whose extension equals to this parameter
     *                          null if no specific extension is required
     * @return map from fully qualified class name to filename for scanned source files.
     */
    public static Map<String, String> scan(String sourceDir, String requiredExtension) {
        final String sourceDirWithSeparator = sourceDir.endsWith(File.separator) ? sourceDir
                : sourceDir + File.separator;
        final File dir = new File(sourceDirWithSeparator);
        if (!dir.exists() || !dir.isDirectory()) {
            return Collections.emptyMap();
        }

        // suppress the warning because of inconsistent FileUtils interface
        @SuppressWarnings("unchecked")
        final Collection<File> files = (Collection<File>) FileUtils.listFiles(dir, null, true);
        final Map<String, String> classFileNames = new HashMap<String, String>();
        final int prefixLength = sourceDirWithSeparator.length();
        for (File f : files) {
            assert (f.exists() && f.isFile());

            final int extensionIndex = f.getName().lastIndexOf('.');
            final String filePath = f.getPath();
            if (extensionIndex < 0 || !filePath.startsWith(sourceDirWithSeparator)) {
                continue;
            }

            final int reverseExtensionIndex = f.getName().length() - extensionIndex;
            final String classPathName = filePath.substring(prefixLength,
                    filePath.length() - reverseExtensionIndex);
            if (classPathName.contains(".")) {
                // dot is not allowed in package name, thus not allowed in the directory path
                continue;
            }

            if (requiredExtension != null) {
                final String extension = f.getName().substring(extensionIndex + 1);
                if (!extension.equals(requiredExtension)) {
                    continue;
                }
            }
            classFileNames.put(classPathName.replace(File.separator, "."), filePath);
        }

        return classFileNames;
    }
}