Java tutorial
package edu.stanford.nlp.ling; import edu.stanford.nlp.process.Morphology; /** * A WordLemmaTag corresponds to a pair of a tagged (e.g., for part of speech) * word and its lemma. WordLemmaTag is implemented with String-valued word, * lemma and tag. * It implements the Label interface; the {@code value()} method for that * interface corresponds to the word of the WordLemmaTag. * <p> * The equality relation for WordLemmaTag is defined as identity of * word, lemma and tag. * * @author Marie-Catherine de Marneffe */ public class WordLemmaTag implements Label, Comparable<WordLemmaTag>, HasWord, HasTag { private String word; private String lemma; private String tag; private static final String DIVIDER = "/"; public WordLemmaTag(String word) { this.word = word; this.lemma = null; setTag(null); } public WordLemmaTag(Label word) { this(word.value()); } public WordLemmaTag() { } /** * Create a new {@code WordLemmaTag}. * * @param word This word is set as the word of this Label * @param tag The {@code value()} of this Label is set as the * tag of this Label */ public WordLemmaTag(String word, String tag) { WordTag wT = new WordTag(word, tag); this.word = word; this.lemma = Morphology.stemStatic(wT).word(); setTag(tag); } /** * Create a new {@code WordLemmaTag}. * * @param word This word is passed to the supertype constructor * @param lemma The lemma is set as the lemma of this Label * @param tag The {@code value()} of this Label is set as the * tag of this Label */ public WordLemmaTag(String word, String lemma, String tag) { this(word); this.lemma = lemma; setTag(tag); } /** * Create a new {@code WordLemmaTag} from a Label. The value of * the Label corresponds to the word of the WordLemmaTag. * * @param word This word is passed to the supertype constructor * @param tag The {@code value()} of this Label is set as the * tag of this Label */ public WordLemmaTag(Label word, Label tag) { this(word); WordTag wT = new WordTag(word, tag); this.lemma = Morphology.stemStatic(wT).word(); setTag(tag.value()); } /** * Return a String representation of just the "main" value of this Label. * * @return the "value" of the Label */ @Override public String value() { return word; } @Override public String word() { return value(); } /** * Set the value for the Label. * * @param value the value for the Label */ @Override public void setValue(String value) { word = value; } @Override public void setWord(String word) { setValue(word); } public void setLemma(String lemma) { this.lemma = lemma; } /** * Set the tag for the Label. * * @param tag the value for the Label */ @Override public final void setTag(String tag) { this.tag = tag; } @Override public String tag() { return tag; } public String lemma() { return lemma; } /** * Return a String representation of the Label. For a multipart Label, * this will return all parts. * * @return a text representation of the full label contents: word/lemma/tag */ @Override public String toString() { return toString(DIVIDER); } public String toString(String divider) { return word() + divider + lemma + divider + tag; } /** * The String is divided according to the divider character (usually, "/"). * We assume that we can always just divide on the rightmost divider character, * rather than trying to parse up escape sequences. If the divider character isn't found * in the word, then the whole string becomes the word, and lemma and tag * are {@code null}. * We assume that if only one divider character is found, word and tag are present in * the String, and lemma will be computed. * * @param labelStr The word that will go into the {@code WordLemmaTag} */ @Override public void setFromString(String labelStr) { setFromString(labelStr, DIVIDER); } public void setFromString(String labelStr, String divider) { int first = labelStr.indexOf(divider); int second = labelStr.lastIndexOf(divider); if (first == second) { setWord(labelStr.substring(0, first)); setTag(labelStr.substring(first + 1)); setLemma(Morphology.lemmaStatic(labelStr.substring(0, first), labelStr.substring(first + 1))); } else if (first >= 0) { setWord(labelStr.substring(0, first)); setLemma(labelStr.substring(first + 1, second)); setTag(labelStr.substring(second + 1)); } else { setWord(labelStr); setLemma(null); setTag(null); } } /** * Equality is satisfied only if the compared object is a WordLemmaTag * and has String-equal word, lemma and tag fields. */ @Override public boolean equals(Object o) { if (this == o) return true; if (!(o instanceof WordLemmaTag)) return false; final WordLemmaTag other = (WordLemmaTag) o; return word().equals(other.word()) && lemma().equals(other.lemma()) && tag().equals(other.tag()); } @Override public int hashCode() { int result; result = (word != null ? word.hashCode() : 3); result = 29 * result + (tag != null ? tag.hashCode() : 0); result = 29 * result + (lemma != null ? lemma.hashCode() : 0); return result; } /** * Orders first by word, then by lemma, then by tag. * * @param wordLemmaTag object to compare to * @return result (positive if {@code this} is greater than * {@code obj}, 0 if equal, negative otherwise) */ @Override public int compareTo(WordLemmaTag wordLemmaTag) { int first = word().compareTo(wordLemmaTag.word()); if (first != 0) return first; int second = lemma().compareTo(wordLemmaTag.lemma()); if (second != 0) return second; else return tag().compareTo(wordLemmaTag.tag()); } /** * Return a factory for this kind of label * (i.e., {@code TaggedWord}). * The factory returned is always the same one (a singleton). * * @return The label factory */ @Override public LabelFactory labelFactory() { return new WordLemmaTagFactory(); } /*for debugging only*/ public static void main(String[] args) { WordLemmaTag wLT = new WordLemmaTag(); wLT.setFromString("hunter/NN"); System.out.println(wLT.word()); System.out.println(wLT.lemma()); System.out.println(wLT.tag()); WordLemmaTag wLT2 = new WordLemmaTag(); wLT2.setFromString("bought/buy/V"); System.out.println(wLT2.word()); System.out.println(wLT2.lemma()); System.out.println(wLT2.tag()); WordLemmaTag wLT3 = new WordLemmaTag(); wLT2.setFromString("life"); System.out.println(wLT3.word()); System.out.println(wLT3.lemma()); System.out.println(wLT3.tag()); } private static final long serialVersionUID = -5993410244163988138L; }