Java tutorial
/* * 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. */ package org.apache.lucene.codecs.perfield; import java.io.Closeable; import java.io.IOException; import java.util.ArrayList; import java.util.Collection; import java.util.HashMap; import java.util.IdentityHashMap; import java.util.Map; import java.util.ServiceLoader; import java.util.TreeMap; import org.apache.lucene.codecs.DocValuesConsumer; import org.apache.lucene.codecs.DocValuesFormat; import org.apache.lucene.codecs.DocValuesProducer; import org.apache.lucene.codecs.PostingsFormat; import org.apache.lucene.index.BinaryDocValues; import org.apache.lucene.index.DocValuesType; import org.apache.lucene.index.FieldInfo; import org.apache.lucene.index.MergeState; import org.apache.lucene.index.NumericDocValues; import org.apache.lucene.index.SegmentReadState; import org.apache.lucene.index.SegmentWriteState; import org.apache.lucene.index.SortedDocValues; import org.apache.lucene.index.SortedNumericDocValues; import org.apache.lucene.index.SortedSetDocValues; import org.apache.lucene.util.Accountable; import org.apache.lucene.util.Accountables; import org.apache.lucene.util.IOUtils; /** * Enables per field docvalues support. * <p> * Note, when extending this class, the name ({@link #getName}) is * written into the index. In order for the field to be read, the * name must resolve to your implementation via {@link #forName(String)}. * This method uses Java's * {@link ServiceLoader Service Provider Interface} to resolve format names. * <p> * Files written by each docvalues format have an additional suffix containing the * format name. For example, in a per-field configuration instead of <tt>_1.dat</tt> * filenames would look like <tt>_1_Lucene40_0.dat</tt>. * @see ServiceLoader * @lucene.experimental */ public abstract class PerFieldDocValuesFormat extends DocValuesFormat { /** Name of this {@link PostingsFormat}. */ public static final String PER_FIELD_NAME = "PerFieldDV40"; /** {@link FieldInfo} attribute name used to store the * format name for each field. */ public static final String PER_FIELD_FORMAT_KEY = PerFieldDocValuesFormat.class.getSimpleName() + ".format"; /** {@link FieldInfo} attribute name used to store the * segment suffix name for each field. */ public static final String PER_FIELD_SUFFIX_KEY = PerFieldDocValuesFormat.class.getSimpleName() + ".suffix"; /** Sole constructor. */ public PerFieldDocValuesFormat() { super(PER_FIELD_NAME); } @Override public final DocValuesConsumer fieldsConsumer(SegmentWriteState state) throws IOException { return new FieldsWriter(state); } static class ConsumerAndSuffix implements Closeable { DocValuesConsumer consumer; int suffix; @Override public void close() throws IOException { consumer.close(); } } private class FieldsWriter extends DocValuesConsumer { private final Map<DocValuesFormat, ConsumerAndSuffix> formats = new HashMap<>(); private final Map<String, Integer> suffixes = new HashMap<>(); private final SegmentWriteState segmentWriteState; public FieldsWriter(SegmentWriteState state) { segmentWriteState = state; } @Override public void addNumericField(FieldInfo field, DocValuesProducer valuesProducer) throws IOException { getInstance(field).addNumericField(field, valuesProducer); } @Override public void addBinaryField(FieldInfo field, DocValuesProducer valuesProducer) throws IOException { getInstance(field).addBinaryField(field, valuesProducer); } @Override public void addSortedField(FieldInfo field, DocValuesProducer valuesProducer) throws IOException { getInstance(field).addSortedField(field, valuesProducer); } @Override public void addSortedNumericField(FieldInfo field, DocValuesProducer valuesProducer) throws IOException { getInstance(field).addSortedNumericField(field, valuesProducer); } @Override public void addSortedSetField(FieldInfo field, DocValuesProducer valuesProducer) throws IOException { getInstance(field).addSortedSetField(field, valuesProducer); } @Override public void merge(MergeState mergeState) throws IOException { Map<DocValuesConsumer, Collection<String>> consumersToField = new IdentityHashMap<>(); // Group each consumer by the fields it handles for (FieldInfo fi : mergeState.mergeFieldInfos) { // merge should ignore current format for the fields being merged DocValuesConsumer consumer = getInstance(fi, true); Collection<String> fieldsForConsumer = consumersToField.get(consumer); if (fieldsForConsumer == null) { fieldsForConsumer = new ArrayList<>(); consumersToField.put(consumer, fieldsForConsumer); } fieldsForConsumer.add(fi.name); } // Delegate the merge to the appropriate consumer PerFieldMergeState pfMergeState = new PerFieldMergeState(mergeState); try { for (Map.Entry<DocValuesConsumer, Collection<String>> e : consumersToField.entrySet()) { e.getKey().merge(pfMergeState.apply(e.getValue())); } } finally { pfMergeState.reset(); } } private DocValuesConsumer getInstance(FieldInfo field) throws IOException { return getInstance(field, false); } /** * DocValuesConsumer for the given field. * @param field - FieldInfo object. * @param ignoreCurrentFormat - ignore the existing format attributes. * @return DocValuesConsumer for the field. * @throws IOException if there is a low-level IO error */ private DocValuesConsumer getInstance(FieldInfo field, boolean ignoreCurrentFormat) throws IOException { DocValuesFormat format = null; if (field.getDocValuesGen() != -1) { String formatName = null; if (ignoreCurrentFormat == false) { formatName = field.getAttribute(PER_FIELD_FORMAT_KEY); } // this means the field never existed in that segment, yet is applied updates if (formatName != null) { format = DocValuesFormat.forName(formatName); } } if (format == null) { format = getDocValuesFormatForField(field.name); } if (format == null) { throw new IllegalStateException("invalid null DocValuesFormat for field=\"" + field.name + "\""); } final String formatName = format.getName(); field.putAttribute(PER_FIELD_FORMAT_KEY, formatName); Integer suffix = null; ConsumerAndSuffix consumer = formats.get(format); if (consumer == null) { // First time we are seeing this format; create a new instance if (field.getDocValuesGen() != -1) { String suffixAtt = null; if (!ignoreCurrentFormat) { suffixAtt = field.getAttribute(PER_FIELD_SUFFIX_KEY); } // even when dvGen is != -1, it can still be a new field, that never // existed in the segment, and therefore doesn't have the recorded // attributes yet. if (suffixAtt != null) { suffix = Integer.valueOf(suffixAtt); } } if (suffix == null) { // bump the suffix suffix = suffixes.get(formatName); if (suffix == null) { suffix = 0; } else { suffix = suffix + 1; } } suffixes.put(formatName, suffix); final String segmentSuffix = getFullSegmentSuffix(segmentWriteState.segmentSuffix, getSuffix(formatName, Integer.toString(suffix))); consumer = new ConsumerAndSuffix(); consumer.consumer = format.fieldsConsumer(new SegmentWriteState(segmentWriteState, segmentSuffix)); consumer.suffix = suffix; formats.put(format, consumer); } else { // we've already seen this format, so just grab its suffix assert suffixes.containsKey(formatName); suffix = consumer.suffix; } field.putAttribute(PER_FIELD_SUFFIX_KEY, Integer.toString(suffix)); // TODO: we should only provide the "slice" of FIS // that this DVF actually sees ... return consumer.consumer; } @Override public void close() throws IOException { // Close all subs IOUtils.close(formats.values()); } } static String getSuffix(String formatName, String suffix) { return formatName + "_" + suffix; } static String getFullSegmentSuffix(String outerSegmentSuffix, String segmentSuffix) { if (outerSegmentSuffix.length() == 0) { return segmentSuffix; } else { return outerSegmentSuffix + "_" + segmentSuffix; } } private class FieldsReader extends DocValuesProducer { private final Map<String, DocValuesProducer> fields = new TreeMap<>(); private final Map<String, DocValuesProducer> formats = new HashMap<>(); // clone for merge FieldsReader(FieldsReader other) { Map<DocValuesProducer, DocValuesProducer> oldToNew = new IdentityHashMap<>(); // First clone all formats for (Map.Entry<String, DocValuesProducer> ent : other.formats.entrySet()) { DocValuesProducer values = ent.getValue().getMergeInstance(); formats.put(ent.getKey(), values); oldToNew.put(ent.getValue(), values); } // Then rebuild fields: for (Map.Entry<String, DocValuesProducer> ent : other.fields.entrySet()) { DocValuesProducer producer = oldToNew.get(ent.getValue()); assert producer != null; fields.put(ent.getKey(), producer); } } public FieldsReader(final SegmentReadState readState) throws IOException { // Init each unique format: boolean success = false; try { // Read field name -> format name for (FieldInfo fi : readState.fieldInfos) { if (fi.getDocValuesType() != DocValuesType.NONE) { final String fieldName = fi.name; final String formatName = fi.getAttribute(PER_FIELD_FORMAT_KEY); if (formatName != null) { // null formatName means the field is in fieldInfos, but has no docvalues! final String suffix = fi.getAttribute(PER_FIELD_SUFFIX_KEY); if (suffix == null) { throw new IllegalStateException( "missing attribute: " + PER_FIELD_SUFFIX_KEY + " for field: " + fieldName); } DocValuesFormat format = DocValuesFormat.forName(formatName); String segmentSuffix = getFullSegmentSuffix(readState.segmentSuffix, getSuffix(formatName, suffix)); if (!formats.containsKey(segmentSuffix)) { formats.put(segmentSuffix, format.fieldsProducer(new SegmentReadState(readState, segmentSuffix))); } fields.put(fieldName, formats.get(segmentSuffix)); } } } success = true; } finally { if (!success) { IOUtils.closeWhileHandlingException(formats.values()); } } } @Override public NumericDocValues getNumeric(FieldInfo field) throws IOException { DocValuesProducer producer = fields.get(field.name); return producer == null ? null : producer.getNumeric(field); } @Override public BinaryDocValues getBinary(FieldInfo field) throws IOException { DocValuesProducer producer = fields.get(field.name); return producer == null ? null : producer.getBinary(field); } @Override public SortedDocValues getSorted(FieldInfo field) throws IOException { DocValuesProducer producer = fields.get(field.name); return producer == null ? null : producer.getSorted(field); } @Override public SortedNumericDocValues getSortedNumeric(FieldInfo field) throws IOException { DocValuesProducer producer = fields.get(field.name); return producer == null ? null : producer.getSortedNumeric(field); } @Override public SortedSetDocValues getSortedSet(FieldInfo field) throws IOException { DocValuesProducer producer = fields.get(field.name); return producer == null ? null : producer.getSortedSet(field); } @Override public void close() throws IOException { IOUtils.close(formats.values()); } @Override public long ramBytesUsed() { long size = 0; for (Map.Entry<String, DocValuesProducer> entry : formats.entrySet()) { size += (entry.getKey().length() * Character.BYTES) + entry.getValue().ramBytesUsed(); } return size; } @Override public Collection<Accountable> getChildResources() { return Accountables.namedAccountables("format", formats); } @Override public void checkIntegrity() throws IOException { for (DocValuesProducer format : formats.values()) { format.checkIntegrity(); } } @Override public DocValuesProducer getMergeInstance() { return new FieldsReader(this); } @Override public String toString() { return "PerFieldDocValues(formats=" + formats.size() + ")"; } } @Override public final DocValuesProducer fieldsProducer(SegmentReadState state) throws IOException { return new FieldsReader(state); } /** * Returns the doc values format that should be used for writing * new segments of <code>field</code>. * <p> * The field to format mapping is written to the index, so * this method is only invoked when writing, not when reading. */ public abstract DocValuesFormat getDocValuesFormatForField(String field); }