001/* 002 * Copyright 2006 - 2013 003 * Stefan Balev <stefan.balev@graphstream-project.org> 004 * Julien Baudry <julien.baudry@graphstream-project.org> 005 * Antoine Dutot <antoine.dutot@graphstream-project.org> 006 * Yoann Pigné <yoann.pigne@graphstream-project.org> 007 * Guilhelm Savin <guilhelm.savin@graphstream-project.org> 008 * 009 * This file is part of GraphStream <http://graphstream-project.org>. 010 * 011 * GraphStream is a library whose purpose is to handle static or dynamic 012 * graph, create them from scratch, file or any source and display them. 013 * 014 * This program is free software distributed under the terms of two licenses, the 015 * CeCILL-C license that fits European law, and the GNU Lesser General Public 016 * License. You can use, modify and/ or redistribute the software under the terms 017 * of the CeCILL-C license as circulated by CEA, CNRS and INRIA at the following 018 * URL <http://www.cecill.info> or under the terms of the GNU LGPL as published by 019 * the Free Software Foundation, either version 3 of the License, or (at your 020 * option) any later version. 021 * 022 * This program is distributed in the hope that it will be useful, but WITHOUT ANY 023 * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A 024 * PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. 025 * 026 * You should have received a copy of the GNU Lesser General Public License 027 * along with this program. If not, see <http://www.gnu.org/licenses/>. 028 * 029 * The fact that you are presently reading this means that you have had 030 * knowledge of the CeCILL-C and LGPL licenses and that you accept their terms. 031 */ 032package org.graphstream.graph; 033 034import java.util.HashMap; 035 036/** 037 * Definition of some compound value that can be used as attribute and can be 038 * transformed to a hash map. 039 * 040 * <p> 041 * The purpose of this class is to allow to specify how some values are stored 042 * in the graph and can be exported to files (or others) when the graph is 043 * output. Most graph writers can only handle basic types for attributes (when 044 * they are able to store attributes in files). This interface may allow to 045 * store more complex attributes, made of several elements. The DGS writer is 046 * able to understand these kinds of attributes and store them in files. 047 * </p> 048 * 049 * <p> 050 * The compound attribute is made of fields. Each fields has a name and a value. 051 * For these fields to be exported successfully, they must be transformable to a 052 * hash map where each element is indexed by its name (a String). 053 * </p> 054 * 055 * <p> 056 * For the values to be exported successfully, they must either be basic types, 057 * or be themselves instances of CompountAttribute. 058 * </p> 059 */ 060public interface CompoundAttribute { 061 /** 062 * Transforms this object to a hash map where each field is stored as a pair 063 * (key,value) where the key is the field name. As we cannot enforce the 064 * types of the key and value, the key are considered strings (or 065 * Object.toString()). The value is an arbitrary object. 066 * 067 * @return The conversion of this attribute to a hash. 068 */ 069 HashMap<?, ?> toHashMap(); 070 071 /** 072 * The usual key used to store this attribute inside a graph element. 073 * 074 * @return The attribute usual name. 075 */ 076 String getKey(); 077}