CavalliumDBEngine/src/main/java/it/cavallium/dbengine/database/disk/LuceneIndexSnapshot.java

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2020-12-07 22:15:18 +01:00
package it.cavallium.dbengine.database.disk;
import java.io.IOException;
import org.apache.lucene.index.DirectoryReader;
import org.apache.lucene.index.IndexCommit;
import org.apache.lucene.search.IndexSearcher;
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@SuppressWarnings("unused")
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public class LuceneIndexSnapshot {
private final IndexCommit snapshot;
private boolean initialized;
private boolean failed;
private boolean closed;
private DirectoryReader indexReader;
private IndexSearcher indexSearcher;
public LuceneIndexSnapshot(IndexCommit snapshot) {
this.snapshot = snapshot;
}
public IndexCommit getSnapshot() {
return snapshot;
}
/**
* Can be called only if the snapshot has not been closed
* @throws IllegalStateException if closed or failed
*/
public synchronized DirectoryReader getIndexReader() throws IllegalStateException {
openDirectoryIfNeeded();
return indexReader;
}
/**
* Can be called only if the snapshot has not been closed
* @throws IllegalStateException if closed or failed
*/
public synchronized IndexSearcher getIndexSearcher() throws IllegalStateException {
openDirectoryIfNeeded();
return indexSearcher;
}
private synchronized void openDirectoryIfNeeded() throws IllegalStateException {
if (closed) {
throw new IllegalStateException("Snapshot is closed");
}
if (failed) {
throw new IllegalStateException("Snapshot failed to open");
}
if (!initialized) {
try {
indexReader = DirectoryReader.open(snapshot);
indexSearcher = new IndexSearcher(indexReader);
initialized = true;
} catch (IOException e) {
failed = true;
throw new RuntimeException(e);
}
}
}
public synchronized void close() throws IOException {
closed = true;
if (initialized && !failed) {
indexReader.close();
indexReader = null;
indexSearcher = null;
}
}
}