Removing Shiro dependencies from pojo models

[Tauren Mills]

I'm doing a bunch of refactoring of my project right now, breaking out
parts of it into different modules. I'm using maven in my build
process. I'm running into a situation where I have a Shiro dependency
in my "models" module. This makes me think there is probably a better
approach than what I'm using, so I'm hoping someone can provide some
advice. My "models" module has this dependency, and I'd like to remove
it:

        <!-- SHIRO (for the utils package only -->
        <dependency>
            <groupId>org.apache.shiro</groupId>
            <artifactId>shiro-core</artifactId>
        </dependency>

Basically, I have a Member that contains a set of Roles and a set of
Permissions. Each Role also contains a set of Permissions.  I'm using
the folllowing Shiro dependencies in my Permission object:

* ShiroUtils.hasText()
* ShiroUtils.split()

I'm also using the values of the following, but I had to redefine them
since they aren't visible:

WildcardPermission.WILDCARD_TOKEN
WildcardPermission.PART_DIVIDER_TOKEN

Here's my Permission object, with some fluff removed
(getters/setters/equals/etc)...

@Entity
@Table(name="permissions")
@Cache(usage= CacheConcurrencyStrategy.READ_WRITE)
public class Permission extends AbstractEntity implements IEntity {
        private static final long serialVersionUID = 1L;

        // TODO:  Should I do this differently?
        // Copied from tokens from WildcardPermission since they aren't
visible, and it would
        // make this pojo reliant on Shiro classes.
    protected static final String WILDCARD_TOKEN = "*";
    protected static final String PART_DIVIDER_TOKEN = ":";

        private String domain;
        private String actions;
        private String targets;

    /** Creates a domain permission with *all* actions for *all* targets; */
    public Permission() {
        this(null,null,null);
    }
        
    public Permission(String domain) {
        this(domain,null,null);
    }

    public Permission(String domain, String actions) {
        this(domain,actions,null);
    }

    public Permission(String domain, String actions, String targets) {
        if (!StringUtils.hasText(domain)) {
                // No domain specified, so create an All Permission
            this.domain = "*";
                this.actions = actions;
                this.targets = targets;
        }
        else if (domain.contains(PART_DIVIDER_TOKEN)){
                // Make sure that actions and targets are not declared
                if (StringUtils.hasText(actions) || 
StringUtils.hasText(targets)) {
                        throw new IllegalArgumentException("cannot specify 
actions
or targets if domain contains full permissions string");
                }
                // Domain contains a full permission string, so parse it
                String[] parts = StringUtils.split(domain,
PART_DIVIDER_TOKEN.charAt(0));
                if (parts.length > 0) {
                this.domain = parts[0];
                }
                if (parts.length > 1) {
                this.actions = parts[1];
                }
                if (parts.length > 2) {
                this.targets = parts[2];
                }
                return;
        }
        else {
                this.domain = domain;
                this.actions = actions;
                this.targets = targets;
        }
    }

        @Transient
        public String getPermissionString() {
        StringBuilder sb = new StringBuilder(domain);

        if (!StringUtils.hasText(actions)) {
            if (StringUtils.hasText(targets)) {
                sb.append(PART_DIVIDER_TOKEN).append(WILDCARD_TOKEN);
            }
        } else {
            sb.append(PART_DIVIDER_TOKEN).append(actions);
        }
        if (targets != null) {
            sb.append(PART_DIVIDER_TOKEN).append(targets);
        }
        return sb.toString();
        }

}

Ideally, my "models" maven module would have no dependencies on Shiro.
Is there a better approach that I should consider? I don't want to
implement my own version of StringUtils, but would rather not include
all of Shiro core. I was hoping there was a Shiro-utils module.

I realize that much of StringUtils is copied from Spring, but I think
that split() was customized. Also, I really don't want any Spring
dependencies in my "models" either, and currently don't have any.

Thanks,
Tauren