co.elastic.clients.util.ObjectBuilderBase Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of elasticsearch-java Show documentation
Elasticsearch Java API Client
There is a newer version: 8.17.0
/*
 * Licensed to Elasticsearch B.V. under one or more contributor
 * license agreements. See the NOTICE file distributed with
 * this work for additional information regarding copyright
 * ownership. Elasticsearch B.V. 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 co.elastic.clients.util;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Objects;

/**
 * Base class for object builders.
 */
public class ObjectBuilderBase {
    private boolean _used = false;

    protected void _checkSingleUse() {
        if (this._used) {
            throw new IllegalStateException("Object builders can only be used once");
        }
        this._used = true;
    }

    //----- List utilities

    /** A private extension of ArrayList so that we can recognize our own creations */
    static final class InternalList extends ArrayList {
        InternalList() {
        }

        InternalList(Collection c) {
            super(c);
        }
    };

    /** Get a mutable list from the current list value of an object builder property */
    private static  List _mutableList(List list) {
        if (list == null) {
            return new InternalList<>();
        } else if (list instanceof InternalList) {
            return list;
        } else {
            // Adding to a list we don't own: make a defensive copy, also ensuring it is mutable.
            return new InternalList<>(list);
        }
    }

    /** Add a value to a (possibly {@code null}) list */
    @SafeVarargs
    protected static  List _listAdd(List list, T value, T... values) {
        list = _mutableList(list);
        list.add(value);
        if (values.length > 0) {
            list.addAll(Arrays.asList(values));
        }
        return list;
    }

    /** Add all elements of a list to a (possibly {@code null}) list */
    protected static  List _listAddAll(List list, List values) {
        if (list == null) {
            // Keep the original list to avoid an unnecessary copy.
            // It will be copied if we add more values.
            return Objects.requireNonNull(values);
        } else {
            list = _mutableList(list);
            list.addAll(values);
            return list;
        }
    }

    //----- Map utilities

    /** A private extension of HashMap so that we can recognize our own creations */
    private static final class InternalMap extends HashMap {
        InternalMap() {
        }

        InternalMap(Map m) {
            super(m);
        }
    }

    /** Get a mutable map from the current map value of an object builder property */
    private static  Map _mutableMap(Map map) {
        if (map == null) {
            return new InternalMap<>();
        } else if (map instanceof InternalMap) {
            return map;
        } else {
            // Adding to a map we don't own: make a defensive copy, also ensuring it is mutable.
            return new InternalMap<>(map);
        }
    }

    /** Add a value to a (possibly {@code null}) map */
    protected static  Map _mapPut(Map map, K key, V value) {
        map = _mutableMap(map);
        map.put(key, value);
        return map;
    }

    /** Add all elements of a list to a (possibly {@code null}) map */
    protected static  Map _mapPutAll(Map map, Map entries) {
        if (map == null) {
            // Keep the original map to avoid an unnecessary copy.
            // It will be copied if we add more entries.
            return Objects.requireNonNull(entries);
        } else {
            map = _mutableMap(map);
            map.putAll(entries);
            return map;
        }
    }
}