SubstringIndexer.java revision d25372dc8e65a9ed019a88fdf659ca61313f1b31
/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License, Version 1.0 only
* (the "License"). You may not use this file except in compliance
* with the License.
*
* You can obtain a copy of the license at
* trunk/opends/resource/legal-notices/OpenDS.LICENSE
* or https://OpenDS.dev.java.net/OpenDS.LICENSE.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at
* trunk/opends/resource/legal-notices/OpenDS.LICENSE. If applicable,
* add the following below this CDDL HEADER, with the fields enclosed
* by brackets "[]" replaced with your own identifying information:
* Portions Copyright [yyyy] [name of copyright owner]
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* CDDL HEADER END
*
*
* Copyright 2006-2008 Sun Microsystems, Inc.
*/
package org.opends.server.backends.jeb;
import static org.opends.server.loggers.debug.DebugLogger.*;
import org.opends.server.loggers.debug.DebugTracer;
import org.opends.server.types.*;
import java.util.*;
/**
* An implementation of an Indexer for attribute substrings.
*/
public class SubstringIndexer extends Indexer
{
/**
* The tracer object for the debug logger.
*/
private static final DebugTracer TRACER = getTracer();
/**
* The comparator for index keys generated by this class.
*/
private static final Comparator<byte[]> comparator =
new AttributeIndex.KeyComparator();
/**
* The attribute type for which this instance will
* generate index keys.
*/
private AttributeType attributeType;
/**
* The substring length.
*/
private int substrLength;
/**
* Create a new attribute substring indexer for the given index configuration.
* @param attributeType The attribute type for which an indexer is
* required.
* @param substringLength The decomposed substring length.
*/
public SubstringIndexer(AttributeType attributeType, int substringLength)
{
this.attributeType = attributeType;
this.substrLength = substringLength;
}
/**
* Get a string representation of this object. The returned value is
* used to name an index created using this object.
* @return A string representation of this object.
*/
public String toString()
{
return attributeType.getNameOrOID() + ".substring";
}
/**
* Get the comparator that must be used to compare index keys
* generated by this class.
*
* @return A byte array comparator.
*/
public Comparator<byte[]> getComparator()
{
return comparator;
}
/**
* Generate the set of index keys for an entry.
*
* @param entry The entry.
* @param keys The set into which the generated keys will be inserted.
*/
public void indexEntry(Entry entry, Set<byte[]> keys)
{
List<Attribute> attrList =
entry.getAttribute(attributeType);
if (attrList != null)
{
indexAttribute(attrList, keys);
}
}
/**
* Generate the set of index keys to be added and the set of index keys
* to be deleted for an entry that has been replaced.
*
* @param oldEntry The original entry contents.
* @param newEntry The new entry contents.
* @param modifiedKeys The map into which the modified keys will be inserted.
*/
public void replaceEntry(Entry oldEntry, Entry newEntry,
Map<byte[], Boolean> modifiedKeys)
{
List<Attribute> newAttributes = newEntry.getAttribute(attributeType, true);
List<Attribute> oldAttributes = oldEntry.getAttribute(attributeType, true);
indexAttribute(oldAttributes, modifiedKeys, false);
indexAttribute(newAttributes, modifiedKeys, true);
}
/**
* Generate the set of index keys to be added and the set of index keys
* to be deleted for an entry that was modified.
*
* @param oldEntry The original entry contents.
* @param newEntry The new entry contents.
* @param mods The set of modifications that were applied to the entry.
* @param modifiedKeys The map into which the modified keys will be inserted.
*/
public void modifyEntry(Entry oldEntry, Entry newEntry,
List<Modification> mods,
Map<byte[], Boolean> modifiedKeys)
{
List<Attribute> newAttributes = newEntry.getAttribute(attributeType, true);
List<Attribute> oldAttributes = oldEntry.getAttribute(attributeType, true);
indexAttribute(oldAttributes, modifiedKeys, false);
indexAttribute(newAttributes, modifiedKeys, true);
}
/**
* Generate the set of substring index keys for an attribute.
* @param attrList The attribute for which substring keys are required.
* @param keys The set into which the generated keys will be inserted.
*/
private void indexAttribute(List<Attribute> attrList,
Set<byte[]> keys)
{
if (attrList == null) return;
for (Attribute attr : attrList)
{
for (AttributeValue value : attr)
{
try
{
byte[] normalizedBytes = value.getNormalizedValue().value();
substringKeys(normalizedBytes, keys);
}
catch (DirectoryException e)
{
if (debugEnabled())
{
TRACER.debugCaught(DebugLogLevel.ERROR, e);
}
}
}
}
}
/**
* Decompose an attribute value into a set of substring index keys.
* The ID of the entry containing this value should be inserted
* into the list of each of these keys.
*
* @param value A byte array containing the normalized attribute value
* @param set A set into which the keys will be inserted.
*/
private void substringKeys(byte[] value, Set<byte[]> set)
{
byte[] keyBytes;
// Example: The value is ABCDE and the substring length is 3.
// We produce the keys ABC BCD CDE DE E
// To find values containing a short substring such as DE,
// iterate through keys with prefix DE. To find values
// containing a longer substring such as BCDE, read keys
// BCD and CDE.
for (int i = 0, remain = value.length; remain > 0; i++, remain--)
{
int len = Math.min(substrLength, remain);
keyBytes = makeSubstringKey(value, i, len);
set.add(keyBytes);
}
}
/**
* Makes a byte array representing a substring index key for
* one substring of a value.
*
* @param bytes The byte array containing the value
* @param pos The starting position of the substring
* @param len The length of the substring
* @return A byte array containing a substring key
*/
private byte[] makeSubstringKey(byte[] bytes, int pos, int len)
{
byte[] keyBytes = new byte[len];
System.arraycopy(bytes, pos, keyBytes, 0, len);
return keyBytes;
}
/**
* Generate the set of index keys for an attribute.
* @param attrList The attribute to be indexed.
* @param modifiedKeys The map into which the modified
* keys will be inserted.
* @param insert <code>true</code> if generated keys should
* be inserted or <code>false</code> otherwise.
*/
private void indexAttribute(List<Attribute> attrList,
Map<byte[], Boolean> modifiedKeys,
Boolean insert)
{
if (attrList == null) return;
for (Attribute attr : attrList)
{
for (AttributeValue value : attr)
{
try
{
byte[] normalizedBytes = value.getNormalizedValue().value();
substringKeys(normalizedBytes, modifiedKeys, insert);
}
catch (DirectoryException e)
{
if (debugEnabled())
{
TRACER.debugCaught(DebugLogLevel.ERROR, e);
}
}
}
}
}
/**
* Decompose an attribute value into a set of substring index keys.
* The ID of the entry containing this value should be inserted
* into the list of each of these keys.
*
* @param value A byte array containing the normalized attribute value
* @param modifiedKeys The map into which the modified
* keys will be inserted.
* @param insert <code>true</code> if generated keys should
* be inserted or <code>false</code> otherwise.
*/
private void substringKeys(byte[] value,
Map<byte[], Boolean> modifiedKeys,
Boolean insert)
{
byte[] keyBytes;
// Example: The value is ABCDE and the substring length is 3.
// We produce the keys ABC BCD CDE DE E
// To find values containing a short substring such as DE,
// iterate through keys with prefix DE. To find values
// containing a longer substring such as BCDE, read keys
// BCD and CDE.
for (int i = 0, remain = value.length; remain > 0; i++, remain--)
{
int len = Math.min(substrLength, remain);
keyBytes = makeSubstringKey(value, i, len);
Boolean cInsert = modifiedKeys.get(keyBytes);
if(cInsert == null)
{
modifiedKeys.put(keyBytes, insert);
}
else if(!cInsert.equals(insert))
{
modifiedKeys.remove(keyBytes);
}
}
}
}