*
     * @return A {@link CopyOptions} that excludes properties with whitespace values from the operation.
     * @see CopyOptions#excludeWhitespace()
     */
    public static CopyOptions excludeWhitespace() {
        return new CopyOptions().excludeWhitespace();
    }

    /**
     * Returns a {@link CopyOptions} with the specified prefix.
     * <p>

import static org.codelibs.core.beans.util.CopyOptionsUtil.exclude;
import static org.codelibs.core.beans.util.CopyOptionsUtil.excludeNull;
import static org.codelibs.core.beans.util.CopyOptionsUtil.excludeWhitespace;
import static org.codelibs.core.beans.util.CopyOptionsUtil.include;
import static org.codelibs.core.beans.util.CopyOptionsUtil.prefix;
import static org.codelibs.core.collection.CollectionsUtil.newHashMap;

        return this;
    }

    /**
     * Excludes properties with only whitespace from the operation.
     *
     * @return This instance itself
     */
    public CopyOptions excludeWhitespace() {
        excludesWhitespace = true;
        return this;
    }

    /**
     * Specifies the prefix.
     * <p>