--- /dev/null
+package org.apache.lucene.search;
+
+/**
+ * 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.
+ */
+
+import java.io.IOException;
+import java.util.Set;
+import java.util.ArrayList;
+
+import org.apache.lucene.index.Term;
+import org.apache.lucene.index.TermPositions;
+import org.apache.lucene.index.IndexReader;
+import org.apache.lucene.search.Explanation.IDFExplanation;
+import org.apache.lucene.util.ToStringUtils;
+import org.apache.lucene.util.ArrayUtil;
+
+/** A Query that matches documents containing a particular sequence of terms.
+ * A PhraseQuery is built by QueryParser for input like <code>"new york"</code>.
+ *
+ * <p>This query may be combined with other terms or queries with a {@link BooleanQuery}.
+ */
+public class PhraseQuery extends Query {
+ private String field;
+ private ArrayList<Term> terms = new ArrayList<Term>(4);
+ private ArrayList<Integer> positions = new ArrayList<Integer>(4);
+ private int maxPosition = 0;
+ private int slop = 0;
+
+ /** Constructs an empty phrase query. */
+ public PhraseQuery() {}
+
+ /** Sets the number of other words permitted between words in query phrase.
+ If zero, then this is an exact phrase search. For larger values this works
+ like a <code>WITHIN</code> or <code>NEAR</code> operator.
+
+ <p>The slop is in fact an edit-distance, where the units correspond to
+ moves of terms in the query phrase out of position. For example, to switch
+ the order of two words requires two moves (the first move places the words
+ atop one another), so to permit re-orderings of phrases, the slop must be
+ at least two.
+
+ <p>More exact matches are scored higher than sloppier matches, thus search
+ results are sorted by exactness.
+
+ <p>The slop is zero by default, requiring exact matches.*/
+ public void setSlop(int s) { slop = s; }
+ /** Returns the slop. See setSlop(). */
+ public int getSlop() { return slop; }
+
+ /**
+ * Adds a term to the end of the query phrase.
+ * The relative position of the term is the one immediately after the last term added.
+ */
+ public void add(Term term) {
+ int position = 0;
+ if(positions.size() > 0)
+ position = positions.get(positions.size()-1).intValue() + 1;
+
+ add(term, position);
+ }
+
+ /**
+ * Adds a term to the end of the query phrase.
+ * The relative position of the term within the phrase is specified explicitly.
+ * This allows e.g. phrases with more than one term at the same position
+ * or phrases with gaps (e.g. in connection with stopwords).
+ *
+ * @param term
+ * @param position
+ */
+ public void add(Term term, int position) {
+ if (terms.size() == 0)
+ field = term.field();
+ else if (term.field() != field)
+ throw new IllegalArgumentException("All phrase terms must be in the same field: " + term);
+
+ terms.add(term);
+ positions.add(Integer.valueOf(position));
+ if (position > maxPosition) maxPosition = position;
+ }
+
+ /** Returns the set of terms in this phrase. */
+ public Term[] getTerms() {
+ return terms.toArray(new Term[0]);
+ }
+
+ /**
+ * Returns the relative positions of terms in this phrase.
+ */
+ public int[] getPositions() {
+ int[] result = new int[positions.size()];
+ for(int i = 0; i < positions.size(); i++)
+ result[i] = positions.get(i).intValue();
+ return result;
+ }
+
+ @Override
+ public Query rewrite(IndexReader reader) throws IOException {
+ if (terms.size() == 1) {
+ TermQuery tq = new TermQuery(terms.get(0));
+ tq.setBoost(getBoost());
+ return tq;
+ } else
+ return super.rewrite(reader);
+ }
+
+ static class PostingsAndFreq implements Comparable<PostingsAndFreq> {
+ final TermPositions postings;
+ final int docFreq;
+ final int position;
+ final Term term;
+
+ public PostingsAndFreq(TermPositions postings, int docFreq, int position, Term term) {
+ this.postings = postings;
+ this.docFreq = docFreq;
+ this.position = position;
+ this.term = term;
+ }
+
+ public int compareTo(PostingsAndFreq other) {
+ if (docFreq == other.docFreq) {
+ if (position == other.position) {
+ return term.compareTo(other.term);
+ }
+ return position - other.position;
+ }
+ return docFreq - other.docFreq;
+ }
+
+ @Override
+ public int hashCode() {
+ final int prime = 31;
+ int result = 1;
+ result = prime * result + docFreq;
+ result = prime * result + position;
+ result = prime * result + ((term == null) ? 0 : term.hashCode());
+ return result;
+ }
+
+ @Override
+ public boolean equals(Object obj) {
+ if (this == obj) return true;
+ if (obj == null) return false;
+ if (getClass() != obj.getClass()) return false;
+ PostingsAndFreq other = (PostingsAndFreq) obj;
+ if (docFreq != other.docFreq) return false;
+ if (position != other.position) return false;
+ if (term == null) {
+ if (other.term != null) return false;
+ } else if (!term.equals(other.term)) return false;
+ return true;
+ }
+ }
+
+ private class PhraseWeight extends Weight {
+ private final Similarity similarity;
+ private float value;
+ private float idf;
+ private float queryNorm;
+ private float queryWeight;
+ private IDFExplanation idfExp;
+
+ public PhraseWeight(Searcher searcher)
+ throws IOException {
+ this.similarity = getSimilarity(searcher);
+
+ idfExp = similarity.idfExplain(terms, searcher);
+ idf = idfExp.getIdf();
+ }
+
+ @Override
+ public String toString() { return "weight(" + PhraseQuery.this + ")"; }
+
+ @Override
+ public Query getQuery() { return PhraseQuery.this; }
+
+ @Override
+ public float getValue() { return value; }
+
+ @Override
+ public float sumOfSquaredWeights() {
+ queryWeight = idf * getBoost(); // compute query weight
+ return queryWeight * queryWeight; // square it
+ }
+
+ @Override
+ public void normalize(float queryNorm) {
+ this.queryNorm = queryNorm;
+ queryWeight *= queryNorm; // normalize query weight
+ value = queryWeight * idf; // idf for document
+ }
+
+ @Override
+ public Scorer scorer(IndexReader reader, boolean scoreDocsInOrder, boolean topScorer) throws IOException {
+ if (terms.size() == 0) // optimize zero-term case
+ return null;
+
+ PostingsAndFreq[] postingsFreqs = new PostingsAndFreq[terms.size()];
+ for (int i = 0; i < terms.size(); i++) {
+ final Term t = terms.get(i);
+ TermPositions p = reader.termPositions(t);
+ if (p == null)
+ return null;
+ postingsFreqs[i] = new PostingsAndFreq(p, reader.docFreq(t), positions.get(i).intValue(), t);
+ }
+
+ // sort by increasing docFreq order
+ if (slop == 0) {
+ ArrayUtil.mergeSort(postingsFreqs);
+ }
+
+ if (slop == 0) { // optimize exact case
+ ExactPhraseScorer s = new ExactPhraseScorer(this, postingsFreqs, similarity,
+ reader.norms(field));
+ if (s.noDocs) {
+ return null;
+ } else {
+ return s;
+ }
+ } else {
+ return
+ new SloppyPhraseScorer(this, postingsFreqs, similarity, slop,
+ reader.norms(field));
+ }
+ }
+
+ @Override
+ public Explanation explain(IndexReader reader, int doc)
+ throws IOException {
+
+ ComplexExplanation result = new ComplexExplanation();
+ result.setDescription("weight("+getQuery()+" in "+doc+"), product of:");
+
+ StringBuilder docFreqs = new StringBuilder();
+ StringBuilder query = new StringBuilder();
+ query.append('\"');
+ docFreqs.append(idfExp.explain());
+ for (int i = 0; i < terms.size(); i++) {
+ if (i != 0) {
+ query.append(" ");
+ }
+
+ Term term = terms.get(i);
+
+ query.append(term.text());
+ }
+ query.append('\"');
+
+ Explanation idfExpl =
+ new Explanation(idf, "idf(" + field + ":" + docFreqs + ")");
+
+ // explain query weight
+ Explanation queryExpl = new Explanation();
+ queryExpl.setDescription("queryWeight(" + getQuery() + "), product of:");
+
+ Explanation boostExpl = new Explanation(getBoost(), "boost");
+ if (getBoost() != 1.0f)
+ queryExpl.addDetail(boostExpl);
+ queryExpl.addDetail(idfExpl);
+
+ Explanation queryNormExpl = new Explanation(queryNorm,"queryNorm");
+ queryExpl.addDetail(queryNormExpl);
+
+ queryExpl.setValue(boostExpl.getValue() *
+ idfExpl.getValue() *
+ queryNormExpl.getValue());
+
+ result.addDetail(queryExpl);
+
+ // explain field weight
+ Explanation fieldExpl = new Explanation();
+ fieldExpl.setDescription("fieldWeight("+field+":"+query+" in "+doc+
+ "), product of:");
+
+ Scorer scorer = scorer(reader, true, false);
+ if (scorer == null) {
+ return new Explanation(0.0f, "no matching docs");
+ }
+ Explanation tfExplanation = new Explanation();
+ int d = scorer.advance(doc);
+ float phraseFreq;
+ if (d == doc) {
+ phraseFreq = scorer.freq();
+ } else {
+ phraseFreq = 0.0f;
+ }
+
+ tfExplanation.setValue(similarity.tf(phraseFreq));
+ tfExplanation.setDescription("tf(phraseFreq=" + phraseFreq + ")");
+
+ fieldExpl.addDetail(tfExplanation);
+ fieldExpl.addDetail(idfExpl);
+
+ Explanation fieldNormExpl = new Explanation();
+ byte[] fieldNorms = reader.norms(field);
+ float fieldNorm =
+ fieldNorms!=null ? similarity.decodeNormValue(fieldNorms[doc]) : 1.0f;
+ fieldNormExpl.setValue(fieldNorm);
+ fieldNormExpl.setDescription("fieldNorm(field="+field+", doc="+doc+")");
+ fieldExpl.addDetail(fieldNormExpl);
+
+ fieldExpl.setValue(tfExplanation.getValue() *
+ idfExpl.getValue() *
+ fieldNormExpl.getValue());
+
+ result.addDetail(fieldExpl);
+
+ // combine them
+ result.setValue(queryExpl.getValue() * fieldExpl.getValue());
+ result.setMatch(tfExplanation.isMatch());
+ return result;
+ }
+ }
+
+ @Override
+ public Weight createWeight(Searcher searcher) throws IOException {
+ if (terms.size() == 1) { // optimize one-term case
+ Term term = terms.get(0);
+ Query termQuery = new TermQuery(term);
+ termQuery.setBoost(getBoost());
+ return termQuery.createWeight(searcher);
+ }
+ return new PhraseWeight(searcher);
+ }
+
+ /**
+ * @see org.apache.lucene.search.Query#extractTerms(Set)
+ */
+ @Override
+ public void extractTerms(Set<Term> queryTerms) {
+ queryTerms.addAll(terms);
+ }
+
+ /** Prints a user-readable version of this query. */
+ @Override
+ public String toString(String f) {
+ StringBuilder buffer = new StringBuilder();
+ if (field != null && !field.equals(f)) {
+ buffer.append(field);
+ buffer.append(":");
+ }
+
+ buffer.append("\"");
+ String[] pieces = new String[maxPosition + 1];
+ for (int i = 0; i < terms.size(); i++) {
+ int pos = positions.get(i).intValue();
+ String s = pieces[pos];
+ if (s == null) {
+ s = (terms.get(i)).text();
+ } else {
+ s = s + "|" + (terms.get(i)).text();
+ }
+ pieces[pos] = s;
+ }
+ for (int i = 0; i < pieces.length; i++) {
+ if (i > 0) {
+ buffer.append(' ');
+ }
+ String s = pieces[i];
+ if (s == null) {
+ buffer.append('?');
+ } else {
+ buffer.append(s);
+ }
+ }
+ buffer.append("\"");
+
+ if (slop != 0) {
+ buffer.append("~");
+ buffer.append(slop);
+ }
+
+ buffer.append(ToStringUtils.boost(getBoost()));
+
+ return buffer.toString();
+ }
+
+ /** Returns true iff <code>o</code> is equal to this. */
+ @Override
+ public boolean equals(Object o) {
+ if (!(o instanceof PhraseQuery))
+ return false;
+ PhraseQuery other = (PhraseQuery)o;
+ return (this.getBoost() == other.getBoost())
+ && (this.slop == other.slop)
+ && this.terms.equals(other.terms)
+ && this.positions.equals(other.positions);
+ }
+
+ /** Returns a hash code value for this object.*/
+ @Override
+ public int hashCode() {
+ return Float.floatToIntBits(getBoost())
+ ^ slop
+ ^ terms.hashCode()
+ ^ positions.hashCode();
+ }
+
+}
fnp / pylucene.git / blobdiff