LazyAllocationAttributes.java

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/* *********************************************************************** *
 * project: org.matsim.*
 * Attributes.java
 *                                                                         *
 * *********************************************************************** *
 *                                                                         *
 * copyright       : (C) 2019 by the members listed in the COPYING,        *
 *                   LICENSE and WARRANTY file.                            *
 * email           : info at matsim dot org                                *
 *                                                                         *
 * *********************************************************************** *
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU General Public License as published by  *
 *   the Free Software Foundation; either version 2 of the License, or     *
 *   (at your option) any later version.                                   *
 *   See also COPYING, LICENSE and WARRANTY file                           *
 *                                                                         *
 * *********************************************************************** */

 package org.matsim.utils.objectattributes.attributable;

import java.util.*;
import java.util.function.Consumer;
import java.util.function.Supplier;

public final class LazyAllocationAttributes implements Attributes {

    private final Consumer<Attributes> consumer;
    private final Supplier<Attributes> supplier;
    
    public LazyAllocationAttributes(final Consumer<Attributes> consumer, final Supplier<Attributes> supplier) {
        this.consumer = consumer;
        this.supplier = supplier;
    }
    
    @Override
    public Object putAttribute(String attribute, Object value) {
        Attributes attributes = this.supplier.get();
        if (Objects.isNull(attributes)) {
            attributes = new AttributesImpl();
            this.consumer.accept(attributes);
        }
        attributes.putAttribute(attribute, value);
        return null;
    }

    @Override
    public Object getAttribute(String attribute) {
        return null;
    }

    @Override
    public Object removeAttribute(String attribute) {
        return null;
    }

    @Override
    public void clear() {
    }

    @Override
    public Map<String, Object> getAsMap() {
        return Collections.emptyMap();
    }

    @Override
    public int size() {
        return 0;
    }

    @Override
    public boolean isEmpty() {
        return true;
    }
}