001/**
002 * Copyright (c) 2011, The University of Southampton and the individual contributors.
003 * All rights reserved.
004 *
005 * Redistribution and use in source and binary forms, with or without modification,
006 * are permitted provided that the following conditions are met:
007 *
008 *   *  Redistributions of source code must retain the above copyright notice,
009 *      this list of conditions and the following disclaimer.
010 *
011 *   *  Redistributions in binary form must reproduce the above copyright notice,
012 *      this list of conditions and the following disclaimer in the documentation
013 *      and/or other materials provided with the distribution.
014 *
015 *   *  Neither the name of the University of Southampton nor the names of its
016 *      contributors may be used to endorse or promote products derived from this
017 *      software without specific prior written permission.
018 *
019 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
020 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
021 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
022 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
023 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
024 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
025 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
026 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
027 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
028 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
029 */
030package org.openimaj.text.nlp.sentiment.type;
031
032import java.util.HashMap;
033import java.util.HashSet;
034import java.util.Map;
035import java.util.Set;
036
037/**
038 * Encapsulate a simple sentiment that something is positive, negative or
039 * neutral.
040 * 
041 * @author Sina Samangooei (ss@ecs.soton.ac.uk)
042 * 
043 */
044public class BipolarSentiment implements Sentiment {
045        /**
046         * The states of a bipolar sentiment
047         * 
048         * @author Sina Samangooei (ss@ecs.soton.ac.uk)
049         * 
050         */
051        public static enum State {
052                /**
053                 * positive sentiment
054                 */
055                POSITIVE,
056                /**
057                 * negative sentiment
058                 */
059                NEGATIVE,
060                /**
061                 * Neither positive nore negative, neutral sentiment (or objective for
062                 * example)
063                 */
064                NEUTRAL
065        }
066
067        /**
068         * a neutral sentiment instance
069         */
070        public static final BipolarSentiment NEUTRAL = new BipolarSentiment(State.NEUTRAL);
071        /**
072         * a negative sentiment instance
073         */
074        public static final BipolarSentiment NEGATIVE = new BipolarSentiment(State.NEGATIVE);
075        /**
076         * a positive sentiment instance
077         */
078        public static final BipolarSentiment POSITIVE = new BipolarSentiment(State.POSITIVE);
079        private State state;
080
081        /**
082         * Initialize sentiment as {@link State#NEUTRAL}
083         */
084        public BipolarSentiment() {
085                this(State.NEUTRAL);
086        }
087
088        /**
089         * Instantiate the sentiment
090         * 
091         * @param positive
092         */
093        public BipolarSentiment(State positive) {
094                this.state = positive;
095        }
096
097        /**
098         * @return sentiment == NEGATIVE
099         */
100        public boolean negative() {
101                return state == State.NEGATIVE;
102        }
103
104        /**
105         * @return positive
106         */
107        public boolean positive() {
108                return state == State.POSITIVE;
109        }
110
111        /**
112         * @return positive
113         */
114        public boolean neutral() {
115                return state == State.NEUTRAL;
116        }
117
118        /**
119         * @return the bipolar sentiment
120         */
121        public State sentiment() {
122                return state;
123        }
124
125        @Override
126        public Map<String, ?> asMap() {
127                final HashMap<String, Object> ret = new HashMap<String, Object>();
128                ret.put("state", state);
129                return ret;
130        }
131
132        @Override
133        public void fromMap(Map<String, ?> map) throws UnrecognisedMapException {
134                if (!map.containsKey("state")) {
135                        throw new UnrecognisedMapException("state");
136                }
137                this.state = (State) map.get("state");
138        }
139
140        @Override
141        public boolean equals(Object obj) {
142                if (!(obj instanceof BipolarSentiment))
143                        return false;
144                final BipolarSentiment that = (BipolarSentiment) obj;
145                return that.state == this.state;
146        }
147
148        @Override
149        public String toString() {
150                return this.state.name();
151        }
152
153        /**
154         * @return a list of the {@link BipolarSentiment} instances
155         */
156        public static Set<BipolarSentiment> listBipolarSentiment() {
157                final Set<BipolarSentiment> ret = new HashSet<BipolarSentiment>();
158                ret.add(POSITIVE);
159                ret.add(NEUTRAL);
160                ret.add(NEGATIVE);
161                return ret;
162        }
163
164}