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+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF 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
+ *
+ * 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.
+ */
+
+package org.apache.commons.math3.distribution;
+
+import org.apache.commons.math3.exception.OutOfRangeException;
+
+/**
+ * Implementation of the constant real distribution.
+ *
+ * @since 3.4
+ */
+public class ConstantRealDistribution extends AbstractRealDistribution {
+
+ /** Serialization ID */
+ private static final long serialVersionUID = -4157745166772046273L;
+
+ /** Constant value of the distribution */
+ private final double value;
+
+ /**
+ * Create a constant real distribution with the given value.
+ *
+ * @param value the constant value of this distribution
+ */
+ public ConstantRealDistribution(double value) {
+ super(null); // Avoid creating RandomGenerator
+ this.value = value;
+ }
+
+ /** {@inheritDoc} */
+ public double density(double x) {
+ return x == value ? 1 : 0;
+ }
+
+ /** {@inheritDoc} */
+ public double cumulativeProbability(double x) {
+ return x < value ? 0 : 1;
+ }
+
+ /** {@inheritDoc} */
+ @Override
+ public double inverseCumulativeProbability(final double p) throws OutOfRangeException {
+ if (p < 0.0 || p > 1.0) {
+ throw new OutOfRangeException(p, 0, 1);
+ }
+ return value;
+ }
+
+ /** {@inheritDoc} */
+ public double getNumericalMean() {
+ return value;
+ }
+
+ /** {@inheritDoc} */
+ public double getNumericalVariance() {
+ return 0;
+ }
+
+ /** {@inheritDoc} */
+ public double getSupportLowerBound() {
+ return value;
+ }
+
+ /** {@inheritDoc} */
+ public double getSupportUpperBound() {
+ return value;
+ }
+
+ /** {@inheritDoc} */
+ public boolean isSupportLowerBoundInclusive() {
+ return true;
+ }
+
+ /** {@inheritDoc} */
+ public boolean isSupportUpperBoundInclusive() {
+ return true;
+ }
+
+ /** {@inheritDoc} */
+ public boolean isSupportConnected() {
+ return true;
+ }
+
+ /** {@inheritDoc} */
+ @Override
+ public double sample() {
+ return value;
+ }
+
+ /**
+ * Override with no-op (there is no generator).
+ *
+ * @param seed (ignored)
+ */
+ @Override
+ public void reseedRandomGenerator(long seed) {}
+}