/* Copyright 2004, 2005, 2006 Acegi Technology Pty Limited
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.springframework.security.acls.sid;

import org.springframework.security.GrantedAuthority;

import org.springframework.util.Assert;


/**
 * Represents a <code>GrantedAuthority</code> as a <code>Sid</code>.<p>This is a basic implementation that simply
 * uses the <code>String</code>-based principal for <code>Sid</code> comparison. More complex principal objects may
 * wish to provide an alternative <code>Sid</code> implementation that uses some other identifier.</p>
 *
 * @author Ben Alex
 * @version $Id$
 */
public class GrantedAuthoritySid implements Sid {
    //~ Instance fields ================================================================================================

    private String grantedAuthority;

    //~ Constructors ===================================================================================================

    public GrantedAuthoritySid(String grantedAuthority) {
        Assert.hasText(grantedAuthority, "GrantedAuthority required");
        this.grantedAuthority = grantedAuthority;
    }

    public GrantedAuthoritySid(GrantedAuthority grantedAuthority) {
        Assert.notNull(grantedAuthority, "GrantedAuthority required");
        Assert.notNull(grantedAuthority.getAuthority(),
            "This Sid is only compatible with GrantedAuthoritys that provide a non-null getAuthority()");
        this.grantedAuthority = grantedAuthority.getAuthority();
    }

    //~ Methods ========================================================================================================

    public boolean equals(Object object) {
        if ((object == null) || !(object instanceof GrantedAuthoritySid)) {
            return false;
        }

        // Delegate to getGrantedAuthority() to perform actual comparison (both should be identical)
        return ((GrantedAuthoritySid) object).getGrantedAuthority().equals(this.getGrantedAuthority());
    }

    public int hashCode() {
        return this.getGrantedAuthority().hashCode();
    }

    public String getGrantedAuthority() {
        return grantedAuthority;
    }

    public String toString() {
        return "GrantedAuthoritySid[" + this.grantedAuthority + "]";
    }
}
