001: /*
002: * $Id: BaseBTreeIndexLoader.java,v 1.2 2005/05/02 22:22:47 ahimanikya Exp $
003: * =======================================================================
004: * Copyright (c) 2002-2005 Axion Development Team. All rights reserved.
005: *
006: * Redistribution and use in source and binary forms, with or without
007: * modification, are permitted provided that the following conditions
008: * are met:
009: *
010: * 1. Redistributions of source code must retain the above
011: * copyright notice, this list of conditions and the following
012: * disclaimer.
013: *
014: * 2. Redistributions in binary form must reproduce the above copyright
015: * notice, this list of conditions and the following disclaimer in
016: * the documentation and/or other materials provided with the
017: * distribution.
018: *
019: * 3. The names "Tigris", "Axion", nor the names of its contributors may
020: * not be used to endorse or promote products derived from this
021: * software without specific prior written permission.
022: *
023: * 4. Products derived from this software may not be called "Axion", nor
024: * may "Tigris" or "Axion" appear in their names without specific prior
025: * written permission.
026: *
027: * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
028: * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
029: * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
030: * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
031: * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
032: * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
033: * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
034: * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
035: * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
036: * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
037: * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
038: * =======================================================================
039: */
040:
041: package org.axiondb.engine.indexes;
042:
043: import java.io.File;
044: import java.io.IOException;
045: import java.io.ObjectInputStream;
046: import java.io.ObjectOutputStream;
047:
048: import org.axiondb.AxionException;
049: import org.axiondb.Column;
050: import org.axiondb.Index;
051: import org.axiondb.IndexLoader;
052: import org.axiondb.Table;
053: import org.axiondb.io.AxionFileSystem;
054:
055: /**
056: * @version $Revision: 1.2 $ $Date: 2005/05/02 22:22:47 $
057: * @author Dave Pekarek Krohn
058: * @author Ahimanikya Satapathy
059: */
060: public abstract class BaseBTreeIndexLoader implements IndexLoader {
061: protected static AxionFileSystem FS = new AxionFileSystem();
062:
063: public BaseBTreeIndexLoader() {
064: }
065:
066: public Index loadIndex(Table table, File dataDirectory)
067: throws AxionException {
068: ObjectInputStream in = null;
069: try {
070: String name = dataDirectory.getName();
071: File file = new File(dataDirectory, name + ".DATA");
072: in = FS.openObjectInputSteam(file);
073:
074: int ver = in.readInt(); // read version number
075: if (ver != 1) {
076: throw new AxionException("Can't parse data file "
077: + file + " for index " + name
078: + ", unrecognized data file version " + ver);
079: }
080:
081: String col = in.readUTF(); // read column name
082: boolean unique = in.readBoolean(); // read unique flag
083: return makeIndex(name, table.getColumn(col), unique,
084: dataDirectory);
085: } catch (IOException e) {
086: throw new AxionException(e);
087: } finally {
088: FS.closeInputStream(in);
089: }
090: }
091:
092: public void saveIndex(Index index, File dataDirectory)
093: throws AxionException {
094: ObjectOutputStream out = null;
095: try {
096: String name = index.getName();
097: File file = new File(dataDirectory, name + ".DATA");
098: out = FS.createObjectOutputSteam(file);
099: out.writeInt(1); // write version number
100: out.writeUTF(index.getIndexedColumn().getName()); // write column name
101: out.writeBoolean(index.isUnique()); // write unique flag
102: } catch (IOException e) {
103: throw new AxionException(e);
104: } finally {
105: FS.closeOutputStream(out);
106: }
107:
108: save(index, dataDirectory);
109: }
110:
111: public abstract void saveIndexAfterTruncate(Index ndx,
112: File dataDirectory) throws AxionException;
113:
114: public abstract void save(Index ndx, File dataDirectory)
115: throws AxionException;
116:
117: protected abstract Index makeIndex(String name, Column col,
118: boolean unique, File dataDirectory) throws AxionException;
119:
120: }
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