/*******************************************************************************
* Copyright (c) 2000, 2003 IBM Corporation and others.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Common Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/cpl-v10.html
*
* Contributors:
* IBM Corporation - initial API and implementation
* MetaMatrix, Inc - repackaging and updates for use as a metadata store
*******************************************************************************/
package org.teiid.designer.core.index;
import java.io.File;
import java.io.IOException;
import java.io.RandomAccessFile;
import org.teiid.designer.legacy.Messages;
/**
* A blocksIndexOutput is used to save an index in a file with the given structure:<br>
* - Signature of the file;<br>
* - FileListBlocks;<br>
* - IndexBlocks;<br>
* - Summary of the index.
*
* @since 8.0
*/
public class BlocksIndexOutput extends IndexOutput {
protected RandomAccessFile indexOut;
protected int blockNum;
protected boolean opened= false;
protected File indexFile;
protected FileListBlock fileListBlock;
protected IndexBlock indexBlock;
protected int numWords= 0;
protected IndexSummary summary;
protected int numFiles= 0;
protected boolean firstInBlock;
protected boolean firstIndexBlock;
protected boolean firstFileListBlock;
/**
* @param indexFile
*/
public BlocksIndexOutput(File indexFile) {
this.indexFile= indexFile;
summary= new IndexSummary();
blockNum= 1;
firstInBlock= true;
firstIndexBlock= true;
firstFileListBlock= true;
}
/**
* @see IndexOutput#addFile
*/
@Override
public void addFile(IndexedFile indexedFile) throws IOException {
if (firstFileListBlock) {
firstInBlock= true;
fileListBlock= new FileListBlock(IIndexConstants.BLOCK_SIZE);
firstFileListBlock= false;
}
if (fileListBlock.addFile(indexedFile)) {
if (firstInBlock) {
summary.addFirstFileInBlock(indexedFile, blockNum);
firstInBlock= false;
}
numFiles++;
} else {
if (fileListBlock.isEmpty()) {
return;
}
flushFiles();
addFile(indexedFile);
}
}
/**
* @see IndexOutput#addWord
*/
@Override
public void addWord(WordEntry entry) throws IOException {
if (firstIndexBlock) {
indexBlock= new GammaCompressedIndexBlock(IIndexConstants.BLOCK_SIZE);
firstInBlock= true;
firstIndexBlock= false;
}
if (entry.getNumRefs() == 0)
return;
if (indexBlock.addEntry(entry)) {
if (firstInBlock) {
summary.addFirstWordInBlock(entry.getWord(), blockNum);
firstInBlock= false;
}
numWords++;
} else { // Failed to add block
if (indexBlock.getOffset() == 0) {
//
// An empty index block is too small to accommodate the word entry
//
throw new BlockIndexException(new String(entry.getWord()), Messages.blockSizeExceeded);
}
flushWords();
addWord(entry);
}
}
/**
* @see IndexOutput#close
*/
@Override
public void close() throws IOException {
if (opened) {
indexOut.close();
summary= null;
numFiles= 0;
opened= false;
}
}
/**
* @see IndexOutput#flush
*/
@Override
public void flush() throws IOException {
summary.setNumFiles(numFiles);
summary.setNumWords(numWords);
indexOut.seek(blockNum * (long) IIndexConstants.BLOCK_SIZE);
summary.write(indexOut);
indexOut.seek(0);
indexOut.writeUTF(IIndexConstants.SIGNATURE);
indexOut.writeInt(blockNum);
}
/**
* Writes the current fileListBlock on the disk and initialises it
* (when it's full or it's the end of the index).
*/
protected void flushFiles() throws IOException {
if (!firstFileListBlock
&& fileListBlock != null) {
fileListBlock.flush();
fileListBlock.write(indexOut, blockNum++);
fileListBlock.clear();
firstInBlock= true;
}
}
/**
* Writes the current indexBlock on the disk and initialises it
* (when it's full or it's the end of the index).
*/
protected void flushWords() throws IOException {
if (!firstInBlock
&& indexBlock != null) { // could have added a document without any indexed word, no block created yet
indexBlock.flush();
indexBlock.write(indexOut, blockNum++);
indexBlock.clear();
firstInBlock= true;
}
}
/**
* @see IndexOutput#getDestination
*/
@Override
public Object getDestination() {
return indexFile;
}
/**
* @see IndexOutput#open
*/
@Override
public void open() throws IOException {
if (!opened) {
summary= new IndexSummary();
numFiles= 0;
numWords= 0;
blockNum= 1;
firstInBlock= true;
firstIndexBlock= true;
firstFileListBlock= true;
indexOut= new SafeRandomAccessFile(this.indexFile, "rw"); //$NON-NLS-1$
opened= true;
}
}
}