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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.random;
import java.util.Collection;
import org.apache.commons.math3.exception.NotANumberException;
import org.apache.commons.math3.exception.NotFiniteNumberException;
import org.apache.commons.math3.exception.NotStrictlyPositiveException;
import org.apache.commons.math3.exception.NumberIsTooLargeException;
/**
* Random data generation utilities.
* @deprecated to be removed in 4.0. Use {@link RandomDataGenerator} directly
* @version $Id: RandomData.java 1416643 2012-12-03 19:37:14Z tn $
*/
public interface RandomData {
/**
* Generates a random string of hex characters of length {@code len}.
*
* The generated string will be random, but not cryptographically
* secure. To generate cryptographically secure strings, use
* {@link #nextSecureHexString(int)}.
*
*
* @param len the length of the string to be generated
* @return a random string of hex characters of length {@code len}
* @throws NotStrictlyPositiveException
* if {@code len <= 0}
*/
String nextHexString(int len) throws NotStrictlyPositiveException;
/**
* Generates a uniformly distributed random integer between {@code lower}
* and {@code upper} (endpoints included).
*
* The generated integer will be random, but not cryptographically secure.
* To generate cryptographically secure integer sequences, use
* {@link #nextSecureInt(int, int)}.
*
*
* @param lower lower bound for generated integer
* @param upper upper bound for generated integer
* @return a random integer greater than or equal to {@code lower}
* and less than or equal to {@code upper}
* @throws NumberIsTooLargeException if {@code lower >= upper}
*/
int nextInt(int lower, int upper) throws NumberIsTooLargeException;
/**
* Generates a uniformly distributed random long integer between
* {@code lower} and {@code upper} (endpoints included).
*
* The generated long integer values will be random, but not
* cryptographically secure. To generate cryptographically secure sequences
* of longs, use {@link #nextSecureLong(long, long)}.
*
*
* @param lower lower bound for generated long integer
* @param upper upper bound for generated long integer
* @return a random long integer greater than or equal to {@code lower} and
* less than or equal to {@code upper}
* @throws NumberIsTooLargeException if {@code lower >= upper}
*/
long nextLong(long lower, long upper) throws NumberIsTooLargeException;
/**
* Generates a random string of hex characters from a secure random
* sequence.
*
* If cryptographic security is not required, use
* {@link #nextHexString(int)}.
*
*
* @param len the length of the string to be generated
* @return a random string of hex characters of length {@code len}
* @throws NotStrictlyPositiveException if {@code len <= 0}
*/
String nextSecureHexString(int len) throws NotStrictlyPositiveException;
/**
* Generates a uniformly distributed random integer between {@code lower}
* and {@code upper} (endpoints included) from a secure random sequence.
*
* Sequences of integers generated using this method will be
* cryptographically secure. If cryptographic security is not required,
* {@link #nextInt(int, int)} should be used instead of this method.
*
* Definition:
*
* Secure Random Sequence
*
* @param lower lower bound for generated integer
* @param upper upper bound for generated integer
* @return a random integer greater than or equal to {@code lower} and less
* than or equal to {@code upper}.
* @throws NumberIsTooLargeException if {@code lower >= upper}.
*/
int nextSecureInt(int lower, int upper) throws NumberIsTooLargeException;
/**
* Generates a uniformly distributed random long integer between
* {@code lower} and {@code upper} (endpoints included) from a secure random
* sequence.
*
* Sequences of long values generated using this method will be
* cryptographically secure. If cryptographic security is not required,
* {@link #nextLong(long, long)} should be used instead of this method.
*
* Definition:
*
* Secure Random Sequence
*
* @param lower lower bound for generated integer
* @param upper upper bound for generated integer
* @return a random long integer greater than or equal to {@code lower} and
* less than or equal to {@code upper}.
* @throws NumberIsTooLargeException if {@code lower >= upper}.
*/
long nextSecureLong(long lower, long upper) throws NumberIsTooLargeException;
/**
* Generates a random value from the Poisson distribution with the given
* mean.
*
* Definition:
*
* Poisson Distribution
*
* @param mean the mean of the Poisson distribution
* @return a random value following the specified Poisson distribution
* @throws NotStrictlyPositiveException if {@code mean <= 0}.
*/
long nextPoisson(double mean) throws NotStrictlyPositiveException;
/**
* Generates a random value from the Normal (or Gaussian) distribution with
* specified mean and standard deviation.
*
* Definition:
*
* Normal Distribution
*
* @param mu the mean of the distribution
* @param sigma the standard deviation of the distribution
* @return a random value following the specified Gaussian distribution
* @throws NotStrictlyPositiveException if {@code sigma <= 0}.
*/
double nextGaussian(double mu, double sigma) throws NotStrictlyPositiveException;
/**
* Generates a random value from the exponential distribution
* with specified mean.
*
* Definition:
*
* Exponential Distribution
*
* @param mean the mean of the distribution
* @return a random value following the specified exponential distribution
* @throws NotStrictlyPositiveException if {@code mean <= 0}.
*/
double nextExponential(double mean) throws NotStrictlyPositiveException;
/**
* Generates a uniformly distributed random value from the open interval
* {@code (lower, upper)} (i.e., endpoints excluded).
*
* Definition:
*
* Uniform Distribution {@code lower} and {@code upper - lower} are the
*
* location and scale parameters, respectively.
*
* @param lower the exclusive lower bound of the support
* @param upper the exclusive upper bound of the support
* @return a uniformly distributed random value between lower and upper
* (exclusive)
* @throws NumberIsTooLargeException if {@code lower >= upper}
* @throws NotFiniteNumberException if one of the bounds is infinite
* @throws NotANumberException if one of the bounds is NaN
*/
double nextUniform(double lower, double upper)
throws NumberIsTooLargeException, NotFiniteNumberException, NotANumberException;
/**
* Generates a uniformly distributed random value from the interval
* {@code (lower, upper)} or the interval {@code [lower, upper)}. The lower
* bound is thus optionally included, while the upper bound is always
* excluded.
*
* Definition:
*
* Uniform Distribution {@code lower} and {@code upper - lower} are the
*
* location and scale parameters, respectively.
*
* @param lower the lower bound of the support
* @param upper the exclusive upper bound of the support
* @param lowerInclusive {@code true} if the lower bound is inclusive
* @return uniformly distributed random value in the {@code (lower, upper)}
* interval, if {@code lowerInclusive} is {@code false}, or in the
* {@code [lower, upper)} interval, if {@code lowerInclusive} is
* {@code true}
* @throws NumberIsTooLargeException if {@code lower >= upper}
* @throws NotFiniteNumberException if one of the bounds is infinite
* @throws NotANumberException if one of the bounds is NaN
*/
double nextUniform(double lower, double upper, boolean lowerInclusive)
throws NumberIsTooLargeException, NotFiniteNumberException, NotANumberException;
/**
* Generates an integer array of length {@code k} whose entries are selected
* randomly, without repetition, from the integers {@code 0, ..., n - 1}
* (inclusive).
*
* Generated arrays represent permutations of {@code n} taken {@code k} at a
* time.
*
* @param n the domain of the permutation
* @param k the size of the permutation
* @return a random {@code k}-permutation of {@code n}, as an array of
* integers
* @throws NumberIsTooLargeException if {@code k > n}.
* @throws NotStrictlyPositiveException if {@code k <= 0}.
*/
int[] nextPermutation(int n, int k)
throws NumberIsTooLargeException, NotStrictlyPositiveException;
/**
* Returns an array of {@code k} objects selected randomly from the
* Collection {@code c}.
*
* Sampling from {@code c} is without replacement; but if {@code c} contains
* identical objects, the sample may include repeats. If all elements of
* {@code c} are distinct, the resulting object array represents a
*
* Simple Random Sample of size {@code k} from the elements of
* {@code c}.
*
* @param c the collection to be sampled
* @param k the size of the sample
* @return a random sample of {@code k} elements from {@code c}
* @throws NumberIsTooLargeException if {@code k > c.size()}.
* @throws NotStrictlyPositiveException if {@code k <= 0}.
*/
Object[] nextSample(Collection c, int k)
throws NumberIsTooLargeException, NotStrictlyPositiveException;
}