ClassPathUtil.java

/*
 * Copyright (C) 2017 The Guava Authors
 *
 * 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.google.common.util.concurrent;

import static com.google.common.base.StandardSystemProperty.JAVA_CLASS_PATH;
import static com.google.common.base.StandardSystemProperty.PATH_SEPARATOR;

import com.google.common.base.Splitter;
import com.google.common.collect.ImmutableList;
import java.io.File;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLClassLoader;

// TODO(b/65488446): Make this a public API.
/** Utility method to parse the system class path. */
final class ClassPathUtil {
  private ClassPathUtil() {}

  /**
   * Returns the URLs in the class path specified by the {@code java.class.path} {@linkplain
   * System#getProperty system property}.
   */
  // TODO(b/65488446): Make this a public API.
  static URL[] parseJavaClassPath() {
    ImmutableList.Builder<URL> urls = ImmutableList.builder();
    for (String entry : Splitter.on(PATH_SEPARATOR.value()).split(JAVA_CLASS_PATH.value())) {
      try {
        try {
          urls.add(new File(entry).toURI().toURL());
        } catch (SecurityException e) { // File.toURI checks to see if the file is a directory
          urls.add(new URL("file", null, new File(entry).getAbsolutePath()));
        }
      } catch (MalformedURLException e) {
        AssertionError error = new AssertionError("malformed class path entry: " + entry);
        error.initCause(e);
        throw error;
      }
    }
    return urls.build().toArray(new URL[0]);
  }

  /** Returns the URLs in the class path. */
  static URL[] getClassPathUrls() {
    return ClassPathUtil.class.getClassLoader() instanceof URLClassLoader
        ? ((URLClassLoader) ClassPathUtil.class.getClassLoader()).getURLs()
        : parseJavaClassPath();
  }
}