org.opennms.integration.api.v1.util.MutableCollections Maven / Gradle / Ivy
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* This file is part of OpenNMS(R).
*
* Copyright (C) 2019 The OpenNMS Group, Inc.
* OpenNMS(R) is Copyright (C) 1999-2019 The OpenNMS Group, Inc.
*
* OpenNMS(R) is a registered trademark of The OpenNMS Group, Inc.
*
* OpenNMS(R) is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as published
* by the Free Software Foundation, either version 3 of the License,
* or (at your option) any later version.
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
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* along with OpenNMS(R). If not, see:
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*
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package org.opennms.integration.api.v1.util;
import java.util.ArrayList;
import java.util.Collection;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Optional;
import java.util.function.Supplier;
import java.util.stream.Collectors;
import java.util.stream.Stream;
/**
* Convenience Methods for handling mutable Collections.
*/
public class MutableCollections {
/**
* Copy a Collection to a List.
*
* @param toCopy the Collection to copy
* @param listSupplier the supplier for the desired List type
* @return a new List containing the same elements as the given Collection
*/
public static List copyListFromNullable(Collection toCopy, Supplier> listSupplier) {
return Optional.ofNullable(toCopy)
.map(Collection::stream)
.orElseGet(Stream::empty)
.collect(Collectors.toCollection(listSupplier));
}
public static List copyListFromNullable(Collection toCopy) {
return copyListFromNullable(toCopy, ArrayList::new);
}
/**
* Copy a Map.
*
* @param toCopy the Map to copy
* @param mapSupplier the supplier for the desired Map type
* @return a new Map containing the same elements as the given Map
*/
public static Map copyMapFromNullable(Map toCopy, Supplier> mapSupplier) {
Map map = mapSupplier.get();
if (toCopy == null || toCopy.isEmpty()) {
return map;
}
map.putAll(toCopy);
return map;
}
public static Map copyMapFromNullable(Map toCopy) {
return copyMapFromNullable(toCopy, HashMap::new);
}
}