core/src/main/java/org/apache/james/mime4j/util/ByteSequence.java

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 * regarding copyright ownership.  The ASF licenses this file   *
 * to you under the Apache License, Version 2.0 (the            *
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package org.apache.james.mime4j.util;

/**
 * An immutable sequence of bytes.
 */
public interface ByteSequence {

    /**
     * An empty byte sequence.
     */
    ByteSequence EMPTY = new EmptyByteSequence();

    /**
     * Returns the length of this byte sequence.
     *
     * @return the number of <code>byte</code>s in this sequence.
     */
    int length();

    /**
     * Returns the <code>byte</code> value at the specified index.
     *
     * @param index
     *            the index of the <code>byte</code> value to be returned.
     * @return the corresponding <code>byte</code> value
     * @throws IndexOutOfBoundsException
     *             if <code>index &lt; 0 || index &gt;= length()</code>.
     */
    byte byteAt(int index);

    /**
     * Copies the contents of this byte sequence into a newly allocated byte
     * array and returns that array.
     *
     * @return a byte array holding a copy of this byte sequence.
     */
    byte[] toByteArray();

}