FileDocCategorySizeDatePackage
RangeQuery.javaAPI DocApache Lucene 1.4.35277Tue Mar 30 00:48:04 BST 2004org.apache.lucene.search

RangeQuery

public class RangeQuery extends Query
A Query that matches documents within an exclusive range.
version
$Id: RangeQuery.java,v 1.12 2004/03/29 22:48:03 cutting Exp $

Fields Summary
private Term
lowerTerm
private Term
upperTerm
private boolean
inclusive
Constructors Summary
public RangeQuery(Term lowerTerm, Term upperTerm, boolean inclusive)
Constructs a query selecting all terms greater than lowerTerm but less than upperTerm. There must be at least one term and either term may be null, in which case there is no bound on that side, but if there are two terms, both terms must be for the same field.

        if (lowerTerm == null && upperTerm == null)
        {
            throw new IllegalArgumentException("At least one term must be non-null");
        }
        if (lowerTerm != null && upperTerm != null && lowerTerm.field() != upperTerm.field())
        {
            throw new IllegalArgumentException("Both terms must be for the same field");
        }

        // if we have a lowerTerm, start there. otherwise, start at beginning
        if (lowerTerm != null) {
            this.lowerTerm = lowerTerm;
        }
        else {
            this.lowerTerm = new Term(upperTerm.field(), "");
        }

        this.upperTerm = upperTerm;
        this.inclusive = inclusive;
Methods Summary
public org.apache.lucene.search.Querycombine(org.apache.lucene.search.Query[] queries)

      return Query.mergeBooleanQueries(queries);
public java.lang.StringgetField()
Returns the field name for this query

      return (lowerTerm != null ? lowerTerm.field() : upperTerm.field());
public org.apache.lucene.index.TermgetLowerTerm()
Returns the lower term of this range query

 return lowerTerm;
public org.apache.lucene.index.TermgetUpperTerm()
Returns the upper term of this range query

 return upperTerm;
public booleanisInclusive()
Returns true if the range query is inclusive

 return inclusive;
public org.apache.lucene.search.Queryrewrite(org.apache.lucene.index.IndexReader reader)
FIXME: Describe rewrite method here.

param
reader an IndexReader value
return
a Query value
exception
IOException if an error occurs


        BooleanQuery query = new BooleanQuery();
        TermEnum enumerator = reader.terms(lowerTerm);

        try {

            boolean checkLower = false;
            if (!inclusive) // make adjustments to set to exclusive
                checkLower = true;

            String testField = getField();

            do {
                Term term = enumerator.term();
                if (term != null && term.field() == testField) {
                    if (!checkLower || term.text().compareTo(lowerTerm.text()) > 0) {
                        checkLower = false;
                        if (upperTerm != null) {
                            int compare = upperTerm.text().compareTo(term.text());
                            /* if beyond the upper term, or is exclusive and
                             * this is equal to the upper term, break out */
                            if ((compare < 0) || (!inclusive && compare == 0))
                                break;
                        }
                        TermQuery tq = new TermQuery(term); // found a match
                        tq.setBoost(getBoost()); // set the boost
                        query.add(tq, false, false); // add to query
                    }
                }
                else {
                    break;
                }
            }
            while (enumerator.next());
        }
        finally {
            enumerator.close();
        }
        return query;
public java.lang.StringtoString(java.lang.String field)
Prints a user-readable version of this query.

        StringBuffer buffer = new StringBuffer();
        if (!getField().equals(field))
        {
            buffer.append(getField());
            buffer.append(":");
        }
        buffer.append(inclusive ? "[" : "{");
        buffer.append(lowerTerm != null ? lowerTerm.text() : "null");
        buffer.append(" TO ");
        buffer.append(upperTerm != null ? upperTerm.text() : "null");
        buffer.append(inclusive ? "]" : "}");
        if (getBoost() != 1.0f)
        {
            buffer.append("^");
            buffer.append(Float.toString(getBoost()));
        }
        return buffer.toString();