移位操作

public final class CharArrayBuffer implements Serializable {

    private static final long serialVersionUID = -6208952725094867135L;

    private char[] buffer;
    private int len;

    /**
     * Creates an instance of {@link CharArrayBuffer} with the given initial
     * capacity.
     *
     * @param capacity the capacity
     */
    public CharArrayBuffer(int capacity) {
        super();
        if (capacity < 0) {
            throw new IllegalArgumentException("Buffer capacity may not be negative");
        }
        this.buffer = new char[capacity];
    }

    private void expand(int newlen) {
        char newbuffer[] = new char[Math.max(this.buffer.length << 1, newlen)];
        System.arraycopy(this.buffer, 0, newbuffer, 0, this.len);
        this.buffer = newbuffer;
    }