001/*
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements.  See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership.  The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License.  You may obtain a copy of the License at
009 *
010 *     http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing, software
013 * distributed under the License is distributed on an "AS IS" BASIS,
014 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015 * See the License for the specific language governing permissions and
016 * limitations under the License.
017 */
018package org.apache.hadoop.hbase.util;
019
020import java.net.URL;
021import java.net.URLClassLoader;
022import org.apache.yetus.audience.InterfaceAudience;
023
024import org.apache.hbase.thirdparty.com.google.common.base.Preconditions;
025
026/**
027 * Base class loader that defines couple shared constants used by sub-classes.
028 */
029@InterfaceAudience.Private
030public class ClassLoaderBase extends URLClassLoader {
031
032  protected static final String DEFAULT_LOCAL_DIR = "/tmp/hbase-local-dir";
033  protected static final String LOCAL_DIR_KEY = "hbase.local.dir";
034
035  /**
036   * Parent class loader.
037   */
038  protected final ClassLoader parent;
039
040  /**
041   * Creates a DynamicClassLoader that can load classes dynamically from jar files under a specific
042   * folder.
043   * @param parent the parent ClassLoader to set.
044   */
045  public ClassLoaderBase(final ClassLoader parent) {
046    super(new URL[] {}, parent);
047    Preconditions.checkNotNull(parent, "No parent classloader!");
048    this.parent = parent;
049  }
050
051}