com.greplin.lucene.filter.TermsFilter.java Source code

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Here is the source code for com.greplin.lucene.filter.TermsFilter.java

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/*
 * Copyright 2012 The greplin-lucene-utils Authors.
 *
 * Licensed 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.
 */

package com.greplin.lucene.filter;

import com.google.common.base.Objects;
import com.google.common.collect.Sets;
import org.apache.lucene.index.IndexReader;
import org.apache.lucene.index.Term;
import org.apache.lucene.index.TermDocs;
import org.apache.lucene.search.DocIdSet;
import org.apache.lucene.search.Filter;
import org.apache.lucene.util.FixedBitSet;

import java.io.IOException;
import java.util.Set;

/**
 * Constructs a filter for docs matching any of the terms added to this class.
 */
public class TermsFilter extends Filter {

    /**
     * Terms to match.
     */
    private final Set<Term> terms = Sets.newTreeSet();

    /**
     * Creates a TermsFilter composed from multiple terms.
     * @param terms the terms to add to the filter.
     * @return the new TermsFilter.
     */
    public static TermsFilter from(final Term... terms) {
        TermsFilter filter = new TermsFilter();
        for (Term term : terms) {
            filter.addTerm(term);
        }
        return filter;
    }

    /**
     * Adds a term to the list of acceptable terms.
     * @param term the term to add.
     */
    public void addTerm(final Term term) {
        this.terms.add(term);
    }

    @Override
    public DocIdSet getDocIdSet(final IndexReader reader) throws IOException {
        FixedBitSet result = new FixedBitSet(reader.maxDoc());
        TermDocs td = reader.termDocs();
        try {
            for (Term term : this.terms) {
                td.seek(term);
                while (td.next()) {
                    result.set(td.doc());
                }
            }
        } finally {
            td.close();
        }
        return result;
    }

    @Override
    public boolean equals(final Object obj) {
        if (this == obj) {
            return true;
        }
        if ((obj == null) || (obj.getClass() != this.getClass())) {
            return false;
        }
        TermsFilter that = (TermsFilter) obj;
        return that.terms.equals(this.terms);
    }

    @Override
    public int hashCode() {
        return this.terms.hashCode();
    }

    @Override
    public String toString() {
        return Objects.toStringHelper(TermsFilter.class).add("terms", this.terms).toString();
    }
}