shz.core.queue.a.ConcurrentCArrayQueue Maven / Gradle / Ivy

package shz.core.queue.a;

import shz.core.constant.ArrayConstant;
import shz.core.function.CharConsumer;

import java.util.Objects;

/**
 * 元素类型为char基于循环动态数组的队列
 * 
 * 24+2*n(n为元素个数)=es
 * 
 * B=56+2*n+对齐填充
 */
public class ConcurrentCArrayQueue extends ConcurrentArrayQueue {
    private static final long serialVersionUID = -1886344409984621463L;
    protected char[] es;

    public ConcurrentCArrayQueue(int capacity) {
        super(capacity);
        es = new char[this.capacity];
    }

    public ConcurrentCArrayQueue() {
        this(DEFAULT_CAPACITY);
    }

    public static ConcurrentCArrayQueue of(int capacity) {
        return new ConcurrentCArrayQueue(capacity);
    }

    public static ConcurrentCArrayQueue of() {
        return new ConcurrentCArrayQueue();
    }

    @Override
    protected final void resize(int capacity) {
        char[] temp = new char[capacity];
        for (int i = 0; i < size; ++i) temp[i] = es[(i + head) % this.capacity];
        this.capacity = capacity;
        head = 0;
        tail = size;
        es = temp;
    }

    @Override
    protected final void setNull(int i) {
        es[i] = 0;
    }

    public final void offer(char e) {
        writeLock.lock();
        try {
            beforeOffer();
            es[tail] = e;
            afterOffer();
        } finally {
            writeLock.unlock();
        }
    }

    public final char poll() {
        writeLock.lock();
        try {
            checkEmpty();
            char e = es[head];
            afterPoll();
            return e;
        } finally {
            writeLock.unlock();
        }
    }

    public final char head() {
        readLock.lock();
        try {
            checkEmpty();
            return es[head];
        } finally {
            readLock.unlock();
        }
    }

    public final char tail() {
        readLock.lock();
        try {
            checkEmpty();
            return es[tail == 0 ? capacity - 1 : tail - 1];
        } finally {
            readLock.unlock();
        }
    }

    public final char get(int idx) {
        readLock.lock();
        try {
            if (idx < 0 || idx >= size) throw new IndexOutOfBoundsException();
            return es[(head + idx) % capacity];
        } finally {
            readLock.unlock();
        }
    }

    public final char[] toArray() {
        readLock.lock();
        try {
            if (size == 0) return ArrayConstant.EMPTY_CHAR_ARRAY;
            char[] array = new char[size];
            int idx = 0;
            int current = head;
            while (current != tail) {
                array[idx++] = es[current];
                current = (current + 1) % capacity;
            }
            return array;
        } finally {
            readLock.unlock();
        }
    }

    public final void forEach(CharConsumer action) {
        Objects.requireNonNull(action);
        readLock.lock();
        try {
            int current = head;
            while (current != tail) {
                action.accept(es[current]);
                current = (current + 1) % capacity;
            }
        } finally {
            readLock.unlock();
        }
    }
}