| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you 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 org.apache.tinkerpop.gremlin.structure.io; |
| |
| import org.apache.tinkerpop.gremlin.process.computer.KeyValue; |
| import org.apache.tinkerpop.gremlin.structure.Vertex; |
| |
| import java.io.File; |
| import java.util.Iterator; |
| import java.util.List; |
| |
| /** |
| * Storage is a standard API that providers can implement to allow abstract UNIX-like file system for data sources. |
| * The methods provided by Storage are similar in form and behavior to standard Linux operating system commands. |
| *<ul> |
| * <li>A <b>name pattern</b> (file or directory) is a sequence of characters, not containing "/", leading spaces, trailing spaces. </li> |
| * <li>A <b>name</b> (file or directory name) is a name pattern, not containing "*" or "?".</li> |
| * <li>A <b>pattern</b> is a sequence of names separated with "/", optionally ending at a name pattern. |
| * <pre> |
| * <pattern> ::= <absolute pattern> | |
| * <relative pattern> |
| * <absolute path> ::= / [<relative pattern>] |
| * <relative path> ::= <name> {/ <name>} [/ <name pattern>] [/] | |
| * <name pattern> [/] |
| * </pre></li> |
| * <li>A <b>path</b> is a path is a pattern, not containing any name pattern. </li> |
| * </ul> |
| * NOTE: <ol> |
| * <li>Even though the syntax allows patterns with trailing "/", they are treated as referring the same |
| * file or directory as the path without the trailing / |
| * <li>This is an abstract file system abstracting the underlying physical file system if any. Thus, under Windows the |
| * directories separator is still /, no matter that Windows uses \ |
| * </ol> |
| * @author Marko A. Rodriguez (http://markorodriguez.com) |
| */ |
| public interface Storage { |
| /** |
| * The file and directory names separator in this uniform UNIX-like abstract file system |
| */ |
| String FILE_SEPARATOR = "/"; |
| |
| String ROOT_DIRECTORY = FILE_SEPARATOR; |
| |
| /** |
| * List all the data sources in the root directory. |
| * |
| * @return non-null list of files (data sources) and directories in the root directory (/) |
| * @see #ls(String) |
| */ |
| public List<String> ls(); |
| |
| /** |
| * List all the files (e.g. data sources) and directories matching the location pattern. |
| * |
| * @param pattern non-null pattern specifying a set of files and directories. Cases:<ul> |
| * <li>a path to a file - specifies a single file to list |
| * <li>a path to a directory - specifies all files and directories immediately nested in that directory to list |
| * <li>pattern - specifies a set of files and directories to list |
| * <li>/ - specifies the root directory to list its contents |
| * </ul> |
| * @return non-null list of files (data sources) and directories matching the pattern. |
| */ |
| public List<String> ls(final String pattern); |
| |
| /** |
| * Recursively copy all the data sources from the source location to the target location. |
| * |
| * @param sourcePattern non-null pattern specifying a set of files and directories. Cases:<ul> |
| * <li>a path to a file - specifies a single file |
| * <li>a path to a directory - specifies all files and directories nested (recursively) in that directory |
| * <li>pattern - specifies a set of files and directories |
| * <li>/ - specifies the contents of the root directory (recursively) |
| * </ul> |
| * @param targetDirectory non-null directory where to copy to |
| * @return whether data sources were copied |
| */ |
| public boolean cp(final String sourcePattern, final String targetDirectory); |
| |
| /** |
| * Determine whether the specified location has a data source. |
| * |
| * @param pattern non-null pattern specifying a set of files and directories. Examples:<ul> |
| * <li>a path to a file - specifies a single file |
| * <li>a path to a directory - specifies the contents of that directory as all files and directories immediately nested in it |
| * <li>pattern - specifies a set of files and directories |
| * <li>/ - specifies the immediate contents of the root directory |
| * </ul> |
| * |
| * @return true if the pattern specifies a non-empty set of files and directories |
| */ |
| public boolean exists(final String pattern); |
| |
| /** |
| * Recursively remove the file (data source) at the specified location. |
| * |
| * NOTE: Some implementations derive the notion of the containing directory from the presence of the file, |
| * so removing all files from a directory in those implementations removes also their directory. |
| * |
| * @param pattern non-null pattern specifying a set of files and directories. Examples:<ul> |
| * <li>a path to a file - specifies a single file |
| * <li>a path to a directory - specifies <b>that directory and</b> all files and directories recursively nested in it |
| * <li>pattern - specifies a set of files and directories |
| * <li>/ - specifies the root directory |
| * </ul> |
| * @return true if all specified files and directories were removed |
| */ |
| public boolean rm(final String pattern); |
| |
| /** |
| * Get a string representation of the specified number of lines at the data source location. |
| * |
| * @param location the data source location |
| * @return an iterator of lines |
| */ |
| public default Iterator<String> head(final String location) { |
| return this.head(location, Integer.MAX_VALUE); |
| } |
| |
| /** |
| * Get a string representation of the specified number of lines at the data source location. |
| * |
| * @param location the data source location |
| * @param totalLines the total number of lines to retrieve |
| * @return an iterator of lines. |
| */ |
| public Iterator<String> head(final String location, final int totalLines); |
| |
| /** |
| * Get the vertices at the specified graph location. |
| * |
| * @param location the location of the graph (or the root location and search will be made) |
| * @param readerClass the class of the parser that understands the graph format |
| * @param totalLines the total number of lines of the graph to return |
| * @return an iterator of vertices. |
| */ |
| public Iterator<Vertex> head(final String location, final Class readerClass, final int totalLines); |
| |
| /** |
| * Get the vertices at the specified graph location. |
| * |
| * @param location the location of the graph (or the root location and search will be made) |
| * @param readerClass the class of the parser that understands the graph format |
| * @return an iterator of vertices. |
| */ |
| public default Iterator<Vertex> head(final String location, final Class readerClass) { |
| return this.head(location, readerClass, Integer.MAX_VALUE); |
| } |
| |
| /** |
| * Get the {@link KeyValue} data at the specified memory location. |
| * |
| * @param location the root location of the data |
| * @param memoryKey the memory key |
| * @param readerClass the class of the parser that understands the memory format |
| * @param totalLines the total number of key-values to return |
| * @return an iterator of key-values. |
| */ |
| public <K, V> Iterator<KeyValue<K, V>> head(final String location, final String memoryKey, final Class readerClass, final int totalLines); |
| |
| |
| /** |
| * Get the {@link KeyValue} data at the specified memory location. |
| * |
| * @param location the root location of the data |
| * @param memoryKey the memory key |
| * @param readerClass the class of the parser that understands the memory format |
| * @return an iterator of key-values. |
| */ |
| public default <K, V> Iterator<KeyValue<K, V>> head(final String location, final String memoryKey, final Class readerClass) { |
| return this.head(location, memoryKey, readerClass, Integer.MAX_VALUE); |
| } |
| |
| |
| /** |
| * @param path non-null local file path |
| * @return non-null, not empty path in the {@link Storage} file system. |
| */ |
| public static String toPath(final File path) { |
| return toPath(path.getAbsolutePath()); |
| } |
| |
| /** |
| * @param path non-null local file path |
| * @return non-null, not empty path in the {@link Storage} file system. |
| */ |
| public static String toPath(final String path) { |
| return path.replace("\\", FILE_SEPARATOR); |
| } |
| } |