001/* 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache License, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the License for the specific language governing permissions and 015 * limitations under the License. 016 */ 017package org.apache.commons.vfs2.provider; 018 019import java.util.ArrayList; 020 021import org.apache.commons.vfs2.FileSystemException; 022 023/** 024 * A {@link VfsComponent} that contains a set of sub-components. 025 */ 026public abstract class AbstractVfsContainer extends AbstractVfsComponent { 027 /** 028 * The components contained by this component. 029 */ 030 private final ArrayList<Object> components = new ArrayList<>(); // @GuardedBy("self") 031 032 /** 033 * Adds a sub-component to this component. 034 * <p> 035 * If the sub-component implements {@link VfsComponent}, it is initialised. All sub-components are closed when this 036 * component is closed. 037 * 038 * @param component the component to add. 039 * @throws FileSystemException if any error occurs. 040 */ 041 protected void addComponent(final Object component) throws FileSystemException { 042 synchronized (components) { 043 if (!components.contains(component)) { 044 // Initialise 045 if (component instanceof VfsComponent) { 046 final VfsComponent vfsComponent = (VfsComponent) component; 047 vfsComponent.setLogger(getLogger()); 048 vfsComponent.setContext(getContext()); 049 vfsComponent.init(); 050 } 051 052 // Keep track of component, to close it later 053 components.add(component); 054 } 055 } // synchronized 056 } 057 058 /** 059 * Removes a sub-component from this component. 060 * 061 * @param component the component to remove. 062 */ 063 protected void removeComponent(final Object component) { 064 synchronized (components) { 065 // multiple instances should not happen 066 components.remove(component); 067 } 068 } 069 070 /** 071 * Closes the sub-components of this component. 072 */ 073 @Override 074 public void close() { 075 final Object[] toclose; 076 synchronized (components) { 077 toclose = components.toArray(); 078 components.clear(); 079 } 080 081 // Close all components 082 for (final Object component : toclose) { 083 if (component instanceof VfsComponent) { 084 final VfsComponent vfsComponent = (VfsComponent) component; 085 vfsComponent.close(); 086 } 087 } 088 } 089}