Android Open Source - music-tag Multiple Buffered List

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Back to project page music-tag.

License

The source code is released under:

Apache License

Java Source Code

package binauld.pierre.musictag.collection;
//from ww  w  .j  a va  2 s .  c om

import java.util.Collection;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.ListIterator;
import java.util.Queue;

/**
 * Allow to modify an ArrayList on some thread without hinder read method.
 * Furthermore modification can be retrieve for reading with the push/pull method.
 * Tail represent the most updated list. It is this list you working on.
 *
 * @param <E> @see List
 */
public class MultipleBufferedList<E> implements List<E> {

    /**
     * A factory to build the implementation of lists used by MultipleBufferedList.
     * @param <E> @see List
     */
    public static abstract class ListFactory<E> {
        public abstract List<E> buildEmptyList();
    }

    private ListFactory factory;

    private Queue<List<E>> queue;

    private List<E> head;
    private List<E> tail;

    /**
     * Default constructor.
     * @param factory A factory used to build empty implementation of lists internally used.
     */
    public MultipleBufferedList(ListFactory<E> factory) {
        this.factory = factory;
        this.queue = new LinkedList<>();
        this.tail = this.factory.buildEmptyList();
        this.queue.add(tail);
        this.push();
        this.pull();
    }

    /**
     * Get the working list for more modifying possibilities.
     * The working list represent the most updated list. It is this list you working on.
     * @return The working list.
     */
    public List<E> getWorkingList() {
        return tail;
    }

    /**
     * Push changes made on the tail.
     */
    public void push() {
        List<E> list = factory.buildEmptyList();
        list.addAll(tail);
        tail = list;
        queue.add(tail);
    }

    /**
     * Get the waiting changes pushed for reading.
     */
    public void pull() {
        while(queue.size() > 1) {
            head = queue.poll();
        }
    }

    @Override
    public void add(int location, E object) {
        tail.add(location, object);
    }

    @Override
    public boolean add(E object) {
        return tail.add(object);
    }

    @Override
    public boolean addAll(int location, Collection<? extends E> collection) {
        return tail.addAll(location, collection);
    }

    @Override
    public boolean addAll(Collection<? extends E> collection) {
        return tail.addAll(collection);
    }

    @Override
    public void clear() {
        tail.clear();
    }

    @Override
    public boolean contains(Object object) {
        return head.contains(object);
    }

    @Override
    public boolean containsAll(Collection<?> collection) {
        return head.containsAll(collection);
    }

    @Override
    public E get(int location) {
        return head.get(location);
    }

    @Override
    public int indexOf(Object object) {
        return head.indexOf(object);
    }

    @Override
    public boolean isEmpty() {
        return head.isEmpty();
    }

    @Override
    public Iterator<E> iterator() {
        return head.iterator();
    }

    @Override
    public int lastIndexOf(Object object) {
        return head.lastIndexOf(object);
    }

    @Override
    public ListIterator<E> listIterator() {
        return head.listIterator();
    }

    @Override
    public ListIterator<E> listIterator(int location) {
        return head.listIterator(location);
    }

    @Override
    public E remove(int location) {
        return tail.remove(location);
    }

    @Override
    public boolean remove(Object object) {
        return tail.remove(object);
    }

    @Override
    public boolean removeAll(Collection<?> collection) {
        return tail.removeAll(collection);
    }

    @Override
    public boolean retainAll(Collection<?> collection) {
        return tail.retainAll(collection);
    }

    @Override
    public E set(int location, E object) {
        return tail.set(location, object);
    }

    @Override
    public int size() {
        return head.size();
    }

    @Override
    public List<E> subList(int start, int end) {
        return head.subList(start, end);
    }

    @Override
    public Object[] toArray() {
        return head.toArray();
    }

    @Override
    public <T> T[] toArray(T[] array) {
        return head.toArray(array);
    }
}

Java Source Code List

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