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.configuration2.io;
018
019import java.io.File;
020import java.io.InputStream;
021import java.io.OutputStream;
022import java.net.MalformedURLException;
023import java.net.URL;
024
025import org.apache.commons.configuration2.ex.ConfigurationException;
026
027/**
028 * Abstract layer to allow various types of file systems.
029 *
030 * @since 1.7
031 */
032public abstract class FileSystem {
033    /** Constant for the default logger. */
034    private static final ConfigurationLogger DEFAULT_LOG = ConfigurationLogger.newDummyLogger();
035
036    /** The Logger. */
037    private volatile ConfigurationLogger log;
038
039    /** FileSystem options provider. */
040    private volatile FileOptionsProvider optionsProvider;
041
042    /**
043     * Gets the base path of the given path, for example a directory for a file.
044     *
045     * @param path the source path.
046     * @return the base path.
047     */
048    public abstract String getBasePath(String path);
049
050    /**
051     * Gets the file name of the given path.
052     *
053     * @param path the source path.
054     * @return the file name.
055     */
056    public abstract String getFileName(String path);
057
058    /**
059     * Gets the FileSystem options provider.
060     *
061     * @return the FileSystem options provider.
062     */
063    public FileOptionsProvider getFileOptionsProvider() {
064        return this.optionsProvider;
065    }
066
067    /**
068     * Gets an input stream for a URL.
069     *
070     * @param url the source URL.
071     * @return an input stream.
072     * @throws ConfigurationException if an problem occurs getting the input stream.
073     */
074    public abstract InputStream getInputStream(URL url) throws ConfigurationException;
075
076    /**
077     * Not abstract for binary compatibility.
078     *
079     * @param url TODO
080     * @param urlConnectionOptions Ignored.
081     * @return TODO
082     * @throws ConfigurationException TODO
083     * @since 2.8.0
084     */
085    public InputStream getInputStream(final URL url, final URLConnectionOptions urlConnectionOptions) throws ConfigurationException {
086        return getInputStream(url);
087    }
088
089    /**
090     * Gets the logger used by this FileSystem.
091     *
092     * @return the logger
093     */
094    public ConfigurationLogger getLogger() {
095        final ConfigurationLogger result = log;
096        return result != null ? result : DEFAULT_LOG;
097    }
098
099    /**
100     * Gets an output stream for a File.
101     *
102     * @param file the source File.
103     * @return an output stream.
104     * @throws ConfigurationException if an problem occurs getting the output stream.
105     */
106    public abstract OutputStream getOutputStream(File file) throws ConfigurationException;
107
108    /**
109     * Gets an output stream for a URL.
110     *
111     * @param url the source URL.
112     * @return an output stream.
113     * @throws ConfigurationException if an problem occurs getting the output stream.
114     */
115    public abstract OutputStream getOutputStream(URL url) throws ConfigurationException;
116
117    /**
118     * Gets a path string for the given input where some values may be null.
119     * <p>
120     * The implementation decides on which argument take precedence.
121     * </p>
122     *
123     * @param file A file.
124     * @param url A URL.
125     * @param basePath A base path string.
126     * @param fileName A file name.
127     * @return A path string.
128     */
129    public abstract String getPath(File file, URL url, String basePath, String fileName);
130
131    /**
132     * Gets a URL for a base path and file name.
133     *
134     * @param basePath The base path.
135     * @param fileName The file name.
136     * @return a URL.
137     * @throws MalformedURLException if a problem occurs creating the URL.
138     */
139    public abstract URL getURL(String basePath, String fileName) throws MalformedURLException;
140
141    /**
142     * Locates a URL for a base path and file name.
143     *
144     * @param basePath The base path.
145     * @param fileName The file name.
146     * @return a URL.
147     */
148    public abstract URL locateFromURL(String basePath, String fileName);
149
150    /**
151     * Sets the FileOptionsProvider
152     *
153     * @param provider The FileOptionsProvider
154     */
155    public void setFileOptionsProvider(final FileOptionsProvider provider) {
156        this.optionsProvider = provider;
157    }
158
159    /**
160     * Sets the logger to be used by this FileSystem. This method makes it possible for clients to exactly control
161     * logging behavior. Per default a logger is set that will ignore all log messages. Derived classes that want to enable
162     * logging should call this method during their initialization with the logger to be used. Passing in a <strong>null</strong>
163     * argument disables logging.
164     *
165     * @param log the new logger
166     */
167    public void setLogger(final ConfigurationLogger log) {
168        this.log = log;
169    }
170}