org.trypticon.luceneupgrader.lucene5.internal.lucene.index.IndexCommit Maven / Gradle / Ivy
/*
* 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.trypticon.luceneupgrader.lucene5.internal.lucene.index;
import java.util.Collection;
import java.util.Map;
import java.io.IOException;
import org.trypticon.luceneupgrader.lucene5.internal.lucene.store.Directory;
/**
* Expert: represents a single commit into an index as seen by the
* {@link IndexDeletionPolicy} or {@link IndexReader}.
*
* 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
* (segments_N). This point in time, when the
* action of writing of a new segments file to the directory
* is completed, is an index commit.
*
* 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.
*
* @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 {
/**
* Get the segments file (segments_N) associated
* with this commit point.
*/
public abstract String getSegmentsFileName();
/**
* Returns all index files referenced by this commit point.
*/
public abstract Collection 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.
*
* Upon calling this, the writer is notified that this commit
* point should be deleted.
*
* 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#setCommitData(Map)} for this commit. Map is
* {@code String -> String}. */
public abstract Map 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;
}
}