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RandomAdversary.java
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RandomAdversary.java
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/*
* Copyright (c) 2002-2017 "Neo Technology,"
* Network Engine for Objects in Lund AB [http://neotechnology.com]
*
* This file is part of Neo4j.
*
* Neo4j is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* 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 <http://www.gnu.org/licenses/>.
*/
package org.neo4j.adversaries;
/**
* An adversary that injects failures randomly, based on a configured probability.
*/
@SuppressWarnings( "unchecked" )
public class RandomAdversary extends AbstractAdversary
{
private static final double STANDARD_PROBABILITY_FACTOR = 1.0;
private final double mischiefRate;
private final double failureRate;
private final double errorRate;
private volatile double probabilityFactor;
public RandomAdversary( double mischiefRate, double failureRate, double errorRate )
{
assert 0 <= mischiefRate && mischiefRate < 1.0 :
"Expected mischief rate in [0.0; 1.0[ but was " + mischiefRate;
assert 0 <= failureRate && failureRate < 1.0 :
"Expected failure rate in [0.0; 1.0[ but was " + failureRate;
assert 0 <= errorRate && errorRate < 1.0 :
"Expected error rate in [0.0; 1.0[ but was " + errorRate;
assert mischiefRate + errorRate + failureRate < 1.0 :
"Expected mischief rate + error rate + failure rate in [0.0; 1.0[ but was " +
(mischiefRate + errorRate + failureRate);
this.mischiefRate = mischiefRate;
this.failureRate = failureRate;
this.errorRate = errorRate;
probabilityFactor = STANDARD_PROBABILITY_FACTOR;
}
@Override
public void injectFailure( Class<? extends Throwable>... failureTypes )
{
maybeDoBadStuff( failureTypes, false );
}
@Override
public boolean injectFailureOrMischief( Class<? extends Throwable>... failureTypes )
{
return maybeDoBadStuff( failureTypes, true );
}
private boolean maybeDoBadStuff( Class<? extends Throwable>[] failureTypes, boolean includingMischeif )
{
double luckyDraw = rng.nextDouble();
double factor = probabilityFactor;
boolean resetUponFailure = false;
if ( factor < 0 )
{
resetUponFailure = true;
factor = -factor;
}
if ( luckyDraw <= errorRate * factor )
{
if ( resetUponFailure )
{
probabilityFactor = STANDARD_PROBABILITY_FACTOR;
}
throwOneOf( OutOfMemoryError.class, NullPointerException.class );
}
if ( failureTypes.length > 0 && luckyDraw <= (failureRate + errorRate) * factor )
{
if ( resetUponFailure )
{
probabilityFactor = STANDARD_PROBABILITY_FACTOR;
}
throwOneOf( failureTypes );
}
return includingMischeif && luckyDraw <= (mischiefRate + failureRate + errorRate) * factor;
}
public void setProbabilityFactor( double factor )
{
probabilityFactor = factor;
}
public void setAndResetProbabilityFactor( double factor )
{
// The negative sign bit indicates that the rate should be reset upon failure
probabilityFactor = -factor;
}
}