001    package org.maltparser.ml.lib;
002    
003    import java.io.Serializable;
004    
005    
006    import org.maltparser.core.helper.HashMap;
007    
008    /**
009     * The purpose of the feature map is to map MaltParser's column based features together with the symbol code from the symbol table to 
010     * unique indices suitable for liblinear and libsvm.  A feature column position are combined together with the symbol code in a 
011     * 64-bit key (Long), where 16 bits are reserved for the position and 48 bits are reserved for the symbol code.  
012     * 
013     * @author Johan Hall
014     *
015     */
016    public class FeatureMap  implements Serializable {
017            private static final long serialVersionUID = 7526471155622776147L;
018            private final HashMap<Long,Integer> map;
019            private int featureCounter;
020            
021            /**
022             * Creates a feature map and sets the feature counter to 1
023             */
024            public FeatureMap() {
025                    map = new HashMap<Long, Integer>();
026                    this.featureCounter = 1;
027            }
028            
029            /**
030             * Adds a mapping from a combination of the position in the column-based feature vector and the symbol code to 
031             * an index value suitable for liblinear and libsvm.
032             * 
033             * @param featurePosition a position in the column-based feature vector
034             * @param code a symbol code
035             * @return the index value 
036             */
037            public int addIndex(int featurePosition, int code) {
038                    final long key = ((((long)featurePosition) << 48) | (long)code);
039                    Integer index = map.get(key);
040                    if (index == null) {
041                            index = featureCounter++;
042                            map.put(key, index);
043                    }
044                    return index.intValue();
045            }
046            
047            /**
048             * Return
049             * 
050             * @param featurePosition the position in the column-based feature vector
051             * @param code the symbol code suitable for liblinear and libsvm
052             * @return the index value if it exists, otherwise -1
053             */
054            public int getIndex(int featurePosition, int code) {
055                    final Integer index = map.get(((((long)featurePosition) << 48) | (long)code));
056                    return (index == null)?-1:index;
057            }
058            
059            
060            public int addIndex(int featurePosition, int code1, int code2) {
061                    final long key = ((((long)featurePosition) << 48) | (((long)code1) << 24) | (long)code2);
062                    Integer index = map.get(key);
063                    if (index == null) {
064                            index = featureCounter++;
065                            map.put(key, index);
066                    }
067                    return index.intValue();
068            }
069            
070            public int setIndex(long key, int index) {
071                    return map.put(key, index);
072            }
073            
074            public int decrementIndex(Long key) {
075                    Integer index = map.get(key);
076                    if (index != null) {
077                            map.put(key, index - 1);
078                    }
079                    return (index != null)?index - 1 : -1;
080            }
081            
082            public void decrementfeatureCounter() {
083                    featureCounter--;
084            }
085            
086            public Integer removeIndex(long key) {
087                    return map.remove(key);
088            }
089            
090            public int getIndex(int featurePosition, int code1, int code2) {
091                    final Integer index = map.get(((((long)featurePosition) << 48) | (((long)code1) << 24) | (long)code2));
092                    return (index == null)?-1:index;
093            }
094                    
095            /**
096             * @return the size of the map
097             */
098            public int size() {
099                    return map.size();
100            }
101            
102            
103            public Long[] reverseMap() {
104                    Long[] reverseMap = new Long[map.size() +1];
105    
106                    for (Long key : map.keySet()) {
107                            reverseMap[map.get(key)] = key;
108                    }
109                    return reverseMap;
110            }
111            
112            
113            
114            public void setFeatureCounter(int featureCounter) {
115                    this.featureCounter = featureCounter;
116            }
117    
118            /**
119             * @return the current value of the feature counter.
120             */
121            public int getFeatureCounter() {
122                    return featureCounter;
123            }
124    }