UnivariateDerivative2Field.java
/*
* Licensed to the Hipparchus project under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The Hipparchus project licenses this file to You 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
*
* https://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.
*/
package org.hipparchus.analysis.differentiation;
import java.io.Serializable;
import org.hipparchus.Field;
/** Field for {@link UnivariateDerivative2} instances.
* <p>
* This class is a singleton.
* </p>
* @since 1.7
*/
public class UnivariateDerivative2Field implements Field<UnivariateDerivative2>, Serializable {
/** Serializable version identifier. */
private static final long serialVersionUID = 20200520L;
/** Zero constant. */
private final UnivariateDerivative2 zero;
/** One constant. */
private final UnivariateDerivative2 one;
/** Associated factory for conversions to {@link DerivativeStructure}. */
private final DSFactory factory;
/** Private constructor for the singleton.
*/
private UnivariateDerivative2Field() {
zero = new UnivariateDerivative2(0.0, 0.0, 0.0);
one = new UnivariateDerivative2(1.0, 0.0, 0.0);
factory = new DSFactory(1, 2);
}
/** Get the unique instance.
* @return the unique instance
*/
public static UnivariateDerivative2Field getInstance() {
return LazyHolder.INSTANCE;
}
/** {@inheritDoc} */
@Override
public UnivariateDerivative2 getOne() {
return one;
}
/** {@inheritDoc} */
@Override
public UnivariateDerivative2 getZero() {
return zero;
}
/** Get the factory for converting to {@link DerivativeStructure}.
* <p>
* This factory is used only for conversions. {@code UnivariateDerivative2} by
* itself does not rely at all on {@link DSFactory}, {@link DSCompiler}
* or {@link DerivativeStructure} for its computation. For this reason,
* the factory here is hidden and this method is package private, so
* only {@link UnivariateDerivative2#toDerivativeStructure()} can call it on an
* existing {@link UnivariateDerivative2} instance
* </p>
* @return factory for conversions
*/
DSFactory getConversionFactory() {
return factory;
}
/** {@inheritDoc} */
@Override
public Class<UnivariateDerivative2> getRuntimeClass() {
return UnivariateDerivative2.class;
}
/** {@inheritDoc} */
@Override
public boolean equals(final Object other) {
return this == other;
}
/** {@inheritDoc} */
@Override
public int hashCode() {
return 0x71f43303;
}
// CHECKSTYLE: stop HideUtilityClassConstructor
/** Holder for the instance.
* <p>We use here the Initialization On Demand Holder Idiom.</p>
*/
private static class LazyHolder {
/** Cached field instance. */
private static final UnivariateDerivative2Field INSTANCE = new UnivariateDerivative2Field();
}
// CHECKSTYLE: resume HideUtilityClassConstructor
/** Handle deserialization of the singleton.
* @return the singleton instance
*/
private Object readResolve() {
// return the singleton instance
return LazyHolder.INSTANCE;
}
}