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Lucene example source code file (FrozenBufferedDeletes.java)

This example Lucene source code file (FrozenBufferedDeletes.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Java - Lucene tags/keywords

bytes_per_del_query, bytes_per_del_term, frozenbuffereddeletes, iterable, iterable, iterator, iterator, override, queryandlimit, queryandlimit, string, term, term, unsupportedoperationexception, util

The Lucene FrozenBufferedDeletes.java source code

package org.apache.lucene.index;

/**
 * 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.util.Iterator;
import java.util.Map;

import org.apache.lucene.search.Query;
import org.apache.lucene.util.RamUsageEstimator;
import org.apache.lucene.index.BufferedDeletesStream.QueryAndLimit;

/** Holds buffered deletes by term or query, once pushed.
 *  Pushed deltes are write-once, so we shift to more
 *  memory efficient data structure to hold them.  We don't
 *  hold docIDs because these are applied on flush. */

class FrozenBufferedDeletes {

  /* Rough logic: Term is object w/
     String field and String text (OBJ_HEADER + 2*POINTER).
     We don't count Term's field since it's interned.
     Term's text is String (OBJ_HEADER + 4*INT + POINTER +
     OBJ_HEADER + string.length*CHAR). */
  final static int BYTES_PER_DEL_TERM = 3*RamUsageEstimator.NUM_BYTES_OBJECT_REF + 3*RamUsageEstimator.NUM_BYTES_OBJECT_HEADER + 4*RamUsageEstimator.NUM_BYTES_INT;

  /* Query we often undercount (say 24 bytes), plus int. */
  final static int BYTES_PER_DEL_QUERY = RamUsageEstimator.NUM_BYTES_OBJECT_REF + RamUsageEstimator.NUM_BYTES_INT + 24;

  // Terms, in sorted order:
  // TODO: would be more RAM efficient to store BytesRef[],
  // per field:
  final Term[] terms;

  // Parallel array of deleted query, and the docIDUpto for
  // each
  final Query[] queries;
  final int[] queryLimits;
  final int bytesUsed;
  final int numTermDeletes;
  final long gen;

  public FrozenBufferedDeletes(BufferedDeletes deletes, long gen) {
    terms = deletes.terms.keySet().toArray(new Term[deletes.terms.size()]);
    queries = new Query[deletes.queries.size()];
    queryLimits = new int[deletes.queries.size()];
    int upto = 0;
    for(Map.Entry<Query,Integer> ent : deletes.queries.entrySet()) {
      queries[upto] = ent.getKey();
      queryLimits[upto] = ent.getValue();
      upto++;
    }
    int termDataChars = 0;
    for(Map.Entry<Term,Integer> ent : deletes.terms.entrySet()) {
      final Term term = ent.getKey();
      termDataChars += term.text().length();
    }
    bytesUsed = terms.length * BYTES_PER_DEL_TERM + queries.length * BYTES_PER_DEL_QUERY + termDataChars*RamUsageEstimator.NUM_BYTES_CHAR;
    numTermDeletes = deletes.numTermDeletes.get();
    this.gen = gen;
  }

  public Iterable<Term> termsIterable() {
    return new Iterable<Term>() {
      // @Override -- not until Java 1.6
      public Iterator<Term> iterator() {
        return new Iterator<Term>() {
          private int upto;

          // @Override -- not until Java 1.6
          public boolean hasNext() {
            return upto < terms.length;
          }

          // @Override -- not until Java 1.6
          public Term next() {
            return terms[upto++];
          }

          // @Override -- not until Java 1.6
          public void remove() {
            throw new UnsupportedOperationException();
          }
        };
      }
    };
  }

  public Iterable<QueryAndLimit> queriesIterable() {
    return new Iterable<QueryAndLimit>() {
      // @Override -- not until Java 1.6
      public Iterator<QueryAndLimit> iterator() {
        return new Iterator<QueryAndLimit>() {
          private int upto;

          // @Override -- not until Java 1.6
          public boolean hasNext() {
            return upto < queries.length;
          }

          // @Override -- not until Java 1.6
          public QueryAndLimit next() {
            QueryAndLimit ret = new QueryAndLimit(queries[upto], queryLimits[upto]);
            upto++;
            return ret;
          }

          // @Override -- not until Java 1.6
          public void remove() {
            throw new UnsupportedOperationException();
          }
        };
      }
    };
  }

  @Override
  public String toString() {
    String s = "";
    if (numTermDeletes != 0) {
      s += " " + numTermDeletes + " deleted terms (unique count=" + terms.length + ")";
    }
    if (queries.length != 0) {
      s += " " + queries.length + " deleted queries";
    }
    if (bytesUsed != 0) {
      s += " bytesUsed=" + bytesUsed;
    }

    return s;
  }
  
  boolean any() {
    return terms.length > 0 || queries.length > 0;
  }
}

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