com.unboundid.ldap.sdk.SRVRecordPrioritySet Maven / Gradle / Ivy
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The UnboundID LDAP SDK for Java is a fast, comprehensive, and easy-to-use
Java API for communicating with LDAP directory servers and performing
related tasks like reading and writing LDIF, encoding and decoding data
using base64 and ASN.1 BER, and performing secure communication. This
package contains the Standard Edition of the LDAP SDK, which is a
complete, general-purpose library for communicating with LDAPv3 directory
servers.
/*
* Copyright 2011-2022 Ping Identity Corporation
* All Rights Reserved.
*/
/*
* Copyright 2011-2022 Ping Identity Corporation
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/*
* Copyright (C) 2011-2022 Ping Identity Corporation
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License (GPLv2 only)
* or the terms of the GNU Lesser General Public License (LGPLv2.1 only)
* as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, see .
*/
package com.unboundid.ldap.sdk;
import java.io.Serializable;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;
import java.util.Random;
import com.unboundid.util.NotMutable;
import com.unboundid.util.NotNull;
import com.unboundid.util.ThreadLocalRandom;
import com.unboundid.util.ThreadSafety;
import com.unboundid.util.ThreadSafetyLevel;
/**
* This class provides a data structure for holding information about a set of
* DNS SRV records with the same priority. Records are organized into those
* with nonzero weights and those with zero weights.
*/
@NotMutable()
@ThreadSafety(level=ThreadSafetyLevel.COMPLETELY_THREADSAFE)
final class SRVRecordPrioritySet
implements Serializable
{
/**
* The serial version UID for this serializable class.
*/
private static final long serialVersionUID = -7722028520625558942L;
// The priority for all records in this set.
private final long priority;
// The total weight for all servers in this set.
private final long totalWeight;
// The set of all records in this set.
@NotNull private final List allRecords;
// The set of records with nonzero weights.
@NotNull private final List nonzeroWeightRecords;
// The set of records with zero weights.
@NotNull private final List zeroWeightRecords;
/**
* Creates a new SRV record priority set with the provided records.
*
* @param priority The priority for all records in this set.
* @param records The set of records with the same priority. It must not
* be {@code null} or empty.
*/
SRVRecordPrioritySet(final long priority,
@NotNull final List records)
{
this.priority = priority;
long w = 0L;
final ArrayList nRecords = new ArrayList<>(records.size());
final ArrayList zRecords = new ArrayList<>(records.size());
for (final SRVRecord r : records)
{
if (r.getWeight() == 0L)
{
zRecords.add(r);
}
else
{
nRecords.add(r);
w += r.getWeight();
}
}
totalWeight = w;
allRecords = Collections.unmodifiableList(records);
nonzeroWeightRecords = Collections.unmodifiableList(nRecords);
zeroWeightRecords = Collections.unmodifiableList(zRecords);
}
/**
* Retrieves the priority for all records in this set.
*
* @return The priority for all records in this set.
*/
long getPriority()
{
return priority;
}
/**
* Retrieves a list of SRV records in the order that they should be accessed.
*
* @return A list of SRV records in the order that they should be accessed.
*/
@NotNull()
List getOrderedRecords()
{
final ArrayList records = new ArrayList<>(allRecords.size());
if (! nonzeroWeightRecords.isEmpty())
{
if (nonzeroWeightRecords.size() == 1)
{
records.addAll(nonzeroWeightRecords);
}
else
{
final Random r = ThreadLocalRandom.get();
long tw = totalWeight;
final ArrayList rl = new ArrayList<>(nonzeroWeightRecords);
while (! rl.isEmpty())
{
long w = ((r.nextLong() & 0x7FFF_FFFF_FFFF_FFFFL) % tw);
final Iterator iterator = rl.iterator();
while (iterator.hasNext())
{
final SRVRecord record = iterator.next();
if ((w < record.getWeight()) || (! iterator.hasNext()))
{
iterator.remove();
records.add(record);
tw -= record.getWeight();
break;
}
else
{
w -= record.getWeight();
}
}
}
}
}
records.addAll(zeroWeightRecords);
return records;
}
/**
* Retrieves a string representation of this priority server set.
*
* @return A string representation of this priority server set.
*/
@Override()
@NotNull()
public String toString()
{
final StringBuilder buffer = new StringBuilder();
toString(buffer);
return buffer.toString();
}
/**
* Appends a string representation of this priority buffer set to the provided
* buffer.
*
* @param buffer The buffer to which the information should be appended.
*/
private void toString(@NotNull final StringBuilder buffer)
{
buffer.append("SRVRecordPrioritySet(records={");
final Iterator iterator = allRecords.iterator();
while (iterator.hasNext())
{
buffer.append(iterator.next().toString());
if (iterator.hasNext())
{
buffer.append(", ");
}
}
buffer.append("})");
}
}