/*
* 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.jena.atlas.test;
import static org.apache.jena.atlas.lib.RandomLib.random ;
import java.util.* ;
import java.util.function.IntSupplier;
import java.util.stream.IntStream;
/** Support for testing. May be generally useful */
public class Gen
{
/** Generate a random sequence between low (inclusive) and high (exclusive): may include duplicates. */
public static int[] rand(int numRand, int low, int high) {
return rand(numRand, low, high, false) ;
}
/**
* Generate a random sequence between low (inclusive) and high (exclusive) - with duplicates or not
*/
public static int[] rand(int numRand, int low, int high, boolean allDifferent) {
Set<Integer> used = new HashSet<>();
IntSupplier supplier = allDifferent ? () -> {
int x = oneRandomInt(low, high);
while (!used.add(x)) x = oneRandomInt(low, high);
return x;
} : () -> oneRandomInt(low, high);
return IntStream.generate(supplier).limit(numRand).toArray();
}
private static int oneRandomInt(int low, int high) {
return random.nextInt(high - low) + low;
}
/** Pull items out of the list in a random order */
public static int[] permute(int[] x) {
int[] x2 = Arrays.copyOf(x, x.length);
Collections.shuffle(Arrays.asList(x2), random);
return x2;
}
/** Do a number of random pair-wise swaps */
public static int[] shuffle(int[] x, int num) {
// Collections.shuffle.
int[] x2 = Arrays.copyOf(x, x.length) ;
for ( int i = 0 ; i < num ; i++ ) {
int a = random.nextInt(x2.length) ;
int b = random.nextInt(x2.length) ;
int t = x2[a] ;
x2[a] = x2[b] ;
x2[b] = t ;
}
return x2 ;
}
public static String strings(int[] keys) {
StringJoiner joiner = new StringJoiner(",");
for ( int k : keys ) joiner.add(Integer.toString(k));
return joiner.toString();
}
}