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Provides common core classes and the microkernel powering all Sirius applications

There is a newer version: 12.9.1

/*
 * Made with all the love in the world
 * by scireum in Remshalden, Germany
 *
 * Copyright by scireum GmbH
 * http://www.scireum.de - [email protected]
 */

package sirius.kernel.commons;

import javax.annotation.Nonnull;
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
import java.util.function.Consumer;

/**
 * Provides a pull pattern for asking methods to compute or fill a List.
 * 
 * When asking methods to create or populate a {@link List} it's easier to create and pass along a
 * Collector instead of having each method creating its own list and joining them afterwards.
 * 

 * By subclassing DataCollector one can also directly process the given values instead of just storing them
 * in a list.
 * 

 * A typical use-case is:
 * 
 * {@code
 *             DataCollector<String> collector = new DataCollector<String>();
 *             computeStrings1(collector);
 *             computeStrings2(collector);
 *
 *             collector.getData(); // use values
 * }
 * 
 * 
 * If a sorted list is required which does not depend on insertion order but on a given priority of each entry
 * {@link PriorityCollector} can be used.
 *
 * @param  the type of objects to be collected
 * @see PriorityCollector
 */
public class DataCollector implements Consumer {

    private List data = new ArrayList<>();

    /**
     * Creates a new DataCollector.
     * 

     * Boilerplate method, so one doesn't need to re-type the type parameters.
     *
     * @param  the type of objects created by the data collector
     * @return a new DataCollector
     */
    public static  DataCollector create() {
        return new DataCollector<>();
    }

    /**
     * Adds a value to the collector
     *
     * @param entity contains the value to be added to the collector.
     */
    public void add(T entity) {
        data.add(entity);
    }

    /**
     * Adds all values of the given collection to the collector
     *
     * @param entities the collection of values added to the collector.
     */
    public void addAll(@Nonnull Collection entities) {
        data.addAll(entities);
    }

    /**
     * Returns the List of values which where added to the collector so far.
     * 
     * For the sake of simplicity, this returns the internally used list. Therefore modifying this list, modifies
     * the collector.
     *
     * @return the list of values supplied to the collector so far.
     */
    @Nonnull
    public List getData() {
        return data;
    }

    @Override
    public String toString() {
        return data.toString();
    }

    @Override
    public void accept(T t) {
        add(t);
    }
}