File	Doc	Category	Size	Date	Package
DisjunctionMaxQuery.java	API Doc	Apache Lucene 2.0.0	10538	Fri May 26 09:54:18 BST 2006	org.apache.lucene.search

DisjunctionMaxQuery

• java.lang.Object
  • org.apache.lucene.search.Query

Fields Summary
private ArrayList	disjuncts
private float	tieBreakerMultiplier

Constructors Summary
public DisjunctionMaxQuery(float tieBreakerMultiplier) Creates a new empty DisjunctionMaxQuery. Use add() to add the subqueries. param tieBreakerMultiplier this score of each non-maximum disjunct for a document is multiplied by this weight and added into the final score. If non-zero, the value should be small, on the order of 0.1, which says that 10 occurrences of word in a lower-scored field that is also in a higher scored field is just as good as a unique word in the lower scored field (i.e., one that is not in any higher scored field. this.tieBreakerMultiplier = tieBreakerMultiplier;
public DisjunctionMaxQuery(Collection disjuncts, float tieBreakerMultiplier) Creates a new DisjunctionMaxQuery param disjuncts a Collection of all the disjuncts to add param tieBreakerMultiplier the weight to give to each matching non-maximum disjunct this.tieBreakerMultiplier = tieBreakerMultiplier; add(disjuncts);

Methods Summary
public void	add(org.apache.lucene.search.Query query) Add a subquery to this disjunction param query the disjunct added disjuncts.add(query);
public void	add(java.util.Collection disjuncts) Add a collection of disjuncts to this disjunction via Iterable this.disjuncts.addAll(disjuncts);
public java.lang.Object	clone() Create a shallow copy of us -- used in rewriting if necessary return a copy of us (but reuse, don't copy, our subqueries) DisjunctionMaxQuery clone = (DisjunctionMaxQuery)super.clone(); clone.disjuncts = (ArrayList)this.disjuncts.clone(); return clone;
protected org.apache.lucene.search.Weight	createWeight(org.apache.lucene.search.Searcher searcher) return new DisjunctionMaxWeight(searcher);
public boolean	equals(java.lang.Object o) Return true iff we represent the same query as o param o another object return true iff o is a DisjunctionMaxQuery with the same boost and the same subqueries, in the same order, as us if (! (o instanceof DisjunctionMaxQuery) ) return false; DisjunctionMaxQuery other = (DisjunctionMaxQuery)o; return this.getBoost() == other.getBoost() && this.tieBreakerMultiplier == other.tieBreakerMultiplier && this.disjuncts.equals(other.disjuncts);
public void	extractTerms(java.util.Set terms) for (int i = 0; i < disjuncts.size(); i++) { ((Query)disjuncts.get(i)).extractTerms(terms); }
public int	hashCode() Compute a hash code for hashing us return the hash code return Float.floatToIntBits(getBoost()) + Float.floatToIntBits(tieBreakerMultiplier) + disjuncts.hashCode();
public java.util.Iterator	iterator() An Iterator over the disjuncts return disjuncts.iterator();
public org.apache.lucene.search.Query	rewrite(org.apache.lucene.index.IndexReader reader) Optimize our representation and our subqueries representations param reader the IndexReader we query return an optimized copy of us (which may not be a copy if there is nothing to optimize) if (disjuncts.size() == 1) { Query singleton = (Query) disjuncts.get(0); Query result = singleton.rewrite(reader); if (getBoost() != 1.0f) { if (result == singleton) result = (Query)result.clone(); result.setBoost(getBoost() * result.getBoost()); } return result; } DisjunctionMaxQuery clone = null; for (int i = 0 ; i < disjuncts.size(); i++) { Query clause = (Query) disjuncts.get(i); Query rewrite = clause.rewrite(reader); if (rewrite != clause) { if (clone == null) clone = (DisjunctionMaxQuery)this.clone(); clone.disjuncts.set(i, rewrite); } } if (clone != null) return clone; else return this;
public java.lang.String	toString(java.lang.String field) Prettyprint us. param field the field to which we are applied return a string that shows what we do, of the form "(disjunct1 | disjunct2 | ... | disjunctn)^boost" StringBuffer buffer = new StringBuffer(); buffer.append("("); for (int i = 0 ; i < disjuncts.size(); i++) { Query subquery = (Query) disjuncts.get(i); if (subquery instanceof BooleanQuery) { // wrap sub-bools in parens buffer.append("("); buffer.append(subquery.toString(field)); buffer.append(")"); } else buffer.append(subquery.toString(field)); if (i != disjuncts.size()-1) buffer.append(" | "); } buffer.append(")"); if (tieBreakerMultiplier != 0.0f) { buffer.append("~"); buffer.append(tieBreakerMultiplier); } if (getBoost() != 1.0) { buffer.append("^"); buffer.append(getBoost()); } return buffer.toString();