001: /* Copyright (c) 1995-2000, The Hypersonic SQL Group.
002: * All rights reserved.
003: *
004: * Redistribution and use in source and binary forms, with or without
005: * modification, are permitted provided that the following conditions are met:
006: *
007: * Redistributions of source code must retain the above copyright notice, this
008: * list of conditions and the following disclaimer.
009: *
010: * Redistributions in binary form must reproduce the above copyright notice,
011: * this list of conditions and the following disclaimer in the documentation
012: * and/or other materials provided with the distribution.
013: *
014: * Neither the name of the Hypersonic SQL Group nor the names of its
015: * contributors may be used to endorse or promote products derived from this
016: * software without specific prior written permission.
017: *
018: * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
019: * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
020: * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
021: * ARE DISCLAIMED. IN NO EVENT SHALL THE HYPERSONIC SQL GROUP,
022: * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
023: * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
024: * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
025: * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
026: * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
027: * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
028: * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
029: *
030: * This software consists of voluntary contributions made by many individuals
031: * on behalf of the Hypersonic SQL Group.
032: *
033: *
034: * For work added by the HSQL Development Group:
035: *
036: * Copyright (c) 2001-2005, The HSQL Development Group
037: * All rights reserved.
038: *
039: * Redistribution and use in source and binary forms, with or without
040: * modification, are permitted provided that the following conditions are met:
041: *
042: * Redistributions of source code must retain the above copyright notice, this
043: * list of conditions and the following disclaimer.
044: *
045: * Redistributions in binary form must reproduce the above copyright notice,
046: * this list of conditions and the following disclaimer in the documentation
047: * and/or other materials provided with the distribution.
048: *
049: * Neither the name of the HSQL Development Group nor the names of its
050: * contributors may be used to endorse or promote products derived from this
051: * software without specific prior written permission.
052: *
053: * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
054: * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
055: * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
056: * ARE DISCLAIMED. IN NO EVENT SHALL HSQL DEVELOPMENT GROUP, HSQLDB.ORG,
057: * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
058: * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
059: * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
060: * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
061: * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
062: * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
063: * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
064: */
065:
066: package org.hsqldb;
067:
068: import java.io.IOException;
069:
070: import org.hsqldb.rowio.RowInputInterface;
071: import org.hsqldb.rowio.RowOutputInterface;
072:
073: // fredt@users 20020221 - patch 513005 by sqlbob@users (RMP)
074: // fredt@users 20020920 - path 1.7.1 - refactoring to cut mamory footprint
075: // fredt@users 20021205 - path 1.7.2 - enhancements
076: // fredt@users 20021215 - doc 1.7.2 - javadoc comments
077:
078: /**
079: * The parent for all AVL node implementations, features factory methods for
080: * its subclasses. Subclasses of Node vary in the way they hold
081: * references to other Nodes in the AVL tree, or to their Row data.<br>
082: *
083: * nNext links the Node objects belonging to different indexes for each
084: * table row. It is used solely by Row to locate the node belonging to a
085: * particular index.
086: *
087: *
088: * @author Thomas Mueller (Hypersonic SQL Group)
089: * @version 1.7.2
090: * @since Hypersonic SQL
091: */
092: abstract class Node {
093:
094: static final int NO_POS = CachedRow.NO_POS;
095: int iBalance; // currently, -2 means 'deleted'
096: Node nNext; // node of next index (nNext==null || nNext.iId=iId+1)
097:
098: static final Node newNode(Row r, int id, Table t) {
099:
100: switch (t.getIndexType()) {
101:
102: case Index.MEMORY_INDEX:
103: return new MemoryNode(r);
104:
105: case Index.POINTER_INDEX:
106: return new PointerNode((CachedRow) r, id);
107:
108: case Index.DISK_INDEX:
109: default:
110: return new DiskNode((CachedRow) r, id);
111: }
112: }
113:
114: static final Node newNode(Row r, RowInputInterface in, int id,
115: Table t) throws IOException, HsqlException {
116:
117: switch (t.getIndexType()) {
118:
119: case Index.MEMORY_INDEX:
120: return new MemoryNode(r);
121:
122: case Index.POINTER_INDEX:
123: return new PointerNode((CachedRow) r, id);
124:
125: case Index.DISK_INDEX:
126: default:
127: return new DiskNode((CachedRow) r, in, id);
128: }
129: }
130:
131: /**
132: * This method unlinks the Node from the other Nodes in the same Index
133: * and from the Row.
134: *
135: * It must keep the links between the Nodes in different Indexes.
136: */
137: abstract void delete();
138:
139: /**
140: * File offset of Node. Used with CachedRow objects only
141: */
142: abstract int getKey();
143:
144: /**
145: * Return the Row Object that is linked to this Node.
146: */
147: abstract Row getRow() throws HsqlException;
148:
149: /**
150: * Getters and setters for AVL index operations.
151: */
152: abstract boolean isLeft(Node node) throws HsqlException;
153:
154: abstract boolean isRight(Node node) throws HsqlException;
155:
156: abstract Node getLeft() throws HsqlException;
157:
158: abstract void setLeft(Node n) throws HsqlException;
159:
160: abstract Node getRight() throws HsqlException;
161:
162: abstract void setRight(Node n) throws HsqlException;
163:
164: abstract Node getParent() throws HsqlException;
165:
166: abstract void setParent(Node n) throws HsqlException;
167:
168: final int getBalance() throws HsqlException {
169:
170: if (Trace.DOASSERT) {
171: Trace.doAssert(iBalance != -2);
172: }
173:
174: return iBalance;
175: }
176:
177: abstract void setBalance(int b) throws HsqlException;
178:
179: abstract boolean isRoot();
180:
181: abstract boolean isFromLeft() throws HsqlException;
182:
183: /**
184: * Returns the database table data for this Node
185: *
186: */
187: abstract Object[] getData() throws HsqlException;
188:
189: abstract boolean equals(Node n);
190:
191: /**
192: * Returns the Node Object that currently represents this Node in the
193: * AVL index structure. In current implementations of Node this is
194: * always the same as the this Object for MEMORY and TEXT tables but can
195: * be a different Object for CACHED tables, where DiskNode Objects may
196: * be freed from the Cache. Calling this method returns a Node with
197: * currently valid pointers to its linked AVL Nodes.
198: *
199: */
200: Node getUpdatedNode() throws HsqlException {
201: return this ;
202: }
203:
204: /**
205: * Writes out the node in an implementation dependent way.
206: */
207: abstract void write(RowOutputInterface out) throws IOException;
208:
209: boolean isDeleted() {
210: return iBalance == -2;
211: }
212: }
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