| /* |
| * 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.index; |
| |
| import java.util.Collection; |
| import java.util.Map; |
| import java.io.IOException; |
| |
| import org.apache.lucene.store.Directory; |
| |
| /** |
| * <p>Expert: represents a single commit into an index as seen by the |
| * {@link IndexDeletionPolicy} or {@link IndexReader}.</p> |
| * |
| * <p> Changes to the content of an index are made visible |
| * only after the writer who made that change commits by |
| * writing a new segments file |
| * (<code>segments_N</code>). This point in time, when the |
| * action of writing of a new segments file to the directory |
| * is completed, is an index commit.</p> |
| * |
| * <p>Each index commit point has a unique segments file |
| * associated with it. The segments file associated with a |
| * later index commit point would have a larger N.</p> |
| * |
| * @lucene.experimental |
| */ |
| |
| // TODO: this is now a poor name, because this class also represents a |
| // point-in-time view from an NRT reader |
| public abstract class IndexCommit implements Comparable<IndexCommit> { |
| |
| /** |
| * Get the segments file (<code>segments_N</code>) associated |
| * with this commit point. |
| */ |
| public abstract String getSegmentsFileName(); |
| |
| /** |
| * Returns all index files referenced by this commit point. |
| */ |
| public abstract Collection<String> getFileNames() throws IOException; |
| |
| /** |
| * Returns the {@link Directory} for the index. |
| */ |
| public abstract Directory getDirectory(); |
| |
| /** |
| * Delete this commit point. This only applies when using |
| * the commit point in the context of IndexWriter's |
| * IndexDeletionPolicy. |
| * <p> |
| * Upon calling this, the writer is notified that this commit |
| * point should be deleted. |
| * <p> |
| * Decision that a commit-point should be deleted is taken by the {@link IndexDeletionPolicy} in effect |
| * and therefore this should only be called by its {@link IndexDeletionPolicy#onInit onInit()} or |
| * {@link IndexDeletionPolicy#onCommit onCommit()} methods. |
| */ |
| public abstract void delete(); |
| |
| /** Returns true if this commit should be deleted; this is |
| * only used by {@link IndexWriter} after invoking the |
| * {@link IndexDeletionPolicy}. */ |
| public abstract boolean isDeleted(); |
| |
| /** Returns number of segments referenced by this commit. */ |
| public abstract int getSegmentCount(); |
| |
| /** Sole constructor. (For invocation by subclass |
| * constructors, typically implicit.) */ |
| protected IndexCommit() { |
| } |
| |
| /** Two IndexCommits are equal if both their Directory and versions are equal. */ |
| @Override |
| public boolean equals(Object other) { |
| if (other instanceof IndexCommit) { |
| IndexCommit otherCommit = (IndexCommit) other; |
| return otherCommit.getDirectory() == getDirectory() && otherCommit.getGeneration() == getGeneration(); |
| } else { |
| return false; |
| } |
| } |
| |
| @Override |
| public int hashCode() { |
| return getDirectory().hashCode() + Long.valueOf(getGeneration()).hashCode(); |
| } |
| |
| /** Returns the generation (the _N in segments_N) for this |
| * IndexCommit */ |
| public abstract long getGeneration(); |
| |
| /** Returns userData, previously passed to {@link |
| * IndexWriter#setLiveCommitData(Iterable)} for this commit. Map is |
| * {@code String -> String}. */ |
| public abstract Map<String,String> getUserData() throws IOException; |
| |
| @Override |
| public int compareTo(IndexCommit commit) { |
| if (getDirectory() != commit.getDirectory()) { |
| throw new UnsupportedOperationException("cannot compare IndexCommits from different Directory instances"); |
| } |
| |
| long gen = getGeneration(); |
| long comgen = commit.getGeneration(); |
| return Long.compare(gen, comgen); |
| } |
| |
| /** Package-private API for IndexWriter to init from a commit-point pulled from an NRT or non-NRT reader. */ |
| StandardDirectoryReader getReader() { |
| return null; |
| } |
| } |