http://www.jboss.org/jboss-servlet-api_4.0_spec: The Java Servlet 4.0 API classes (JBoss by Red Hat) 
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package javax.servlet.annotation;

import java.lang.annotation.Documented;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import javax.servlet.annotation.ServletSecurity.EmptyRoleSemantic;
import javax.servlet.annotation.ServletSecurity.TransportGuarantee;


This annotation is used within the ServletSecurity annotation to represent the security constraints to be applied to all HTTP protocol methods for which a corresponding HttpMethodConstraint element does NOT occur within the ServletSecurity annotation. 
For the special case where an @HttpConstraint that returns all default values occurs in combination with at least one HttpMethodConstraint that returns other than all default values, the @HttpConstraint represents that no security constraint is to be
applied to any of the HTTP protocol methods to which a security constraint
would otherwise apply. This exception is made to ensure that such
potentially non-specific uses of @HttpConstraint do not yield
constraints that will explicitly establish unprotected access for such
methods; given that they would not otherwise be covered by a constraint.

Since:Servlet 3.0
/**
 * This annotation is used within the {@link ServletSecurity} annotation to
 * represent the security constraints to be applied to all HTTP protocol
 * methods for which a corresponding {@link HttpMethodConstraint} element does
 * NOT occur within the {@link ServletSecurity} annotation.
 *
 * <p>For the special case where an <code>@HttpConstraint</code> that returns
 * all default values occurs in combination with at least one
 * {@link HttpMethodConstraint} that returns other than all default values, the
 * <code>@HttpConstraint</code> represents that no security constraint is to be
 * applied to any of the HTTP protocol methods to which a security constraint
 * would otherwise apply. This exception is made to ensure that such
 * potentially non-specific uses of <code>@HttpConstraint</code> do not yield
 * constraints that will explicitly establish unprotected access for such
 * methods; given that they would not otherwise be covered by a constraint.
 *
 * @since Servlet 3.0
 */
@Documented
@Retention(RetentionPolicy.RUNTIME)
public @interface HttpConstraint {

    
The default authorization semantic.
This value is insignificant when rolesAllowed returns a
non-empty array, and should not be specified when a non-empty
array is specified for rolesAllowed.

Returns:the EmptyRoleSemantic to be applied when rolesAllowed returns an empty (that is, zero-length) array.
/**
     * The default authorization semantic.
     * This value is insignificant when <code>rolesAllowed</code> returns a
     * non-empty array, and should not be specified when a non-empty
     * array is specified for <tt>rolesAllowed</tt>.
     *
     * @return the {@link EmptyRoleSemantic} to be applied when
     * <code>rolesAllowed</code> returns an empty (that is, zero-length) array.
     */
    EmptyRoleSemantic value() default EmptyRoleSemantic.PERMIT;

    
The data protection requirements (i.e., whether or not SSL/TLS is
required) that must be satisfied by the connections on which requests
arrive.

Returns:the TransportGuarantee indicating the data protection that must be provided by the connection.
/**
     * The data protection requirements (i.e., whether or not SSL/TLS is
     * required) that must be satisfied by the connections on which requests
     * arrive.
     * 
     * @return the {@link TransportGuarantee}
     * indicating the data protection that must be provided by the connection.
     */
    TransportGuarantee transportGuarantee() default TransportGuarantee.NONE;

    
The names of the authorized roles.
Duplicate role names appearing in rolesAllowed are insignificant and
may be discarded during runtime processing of the annotation. The String
"*" has no special meaning as a role name (should it occur in
rolesAllowed).

Returns:an array of zero or more role names. When the array contains
zero elements, its meaning depends on the EmptyRoleSemantic
returned by the value method. If value returns
DENY, and rolesAllowed returns a zero length array,
access is to be denied independent of authentication state and identity.
Conversely, if value returns PERMIT, it
indicates that access is to be allowed independent of authentication
state and identity. When the array contains the names of one or more
roles, it indicates that access is contingent on membership in at
least one of the named roles (independent of the
EmptyRoleSemantic returned by the value method).
/**
     * The names of the authorized roles.
     *
     * Duplicate role names appearing in rolesAllowed are insignificant and
     * may be discarded during runtime processing of the annotation. The String
     * <tt>"*"</tt> has no special meaning as a role name (should it occur in
     * rolesAllowed).
     *
     * @return an array of zero or more role names. When the array contains
     * zero elements, its meaning depends on the <code>EmptyRoleSemantic</code>
     * returned by the <code>value</code> method. If <code>value</code> returns
     * <tt>DENY</tt>, and <code>rolesAllowed</code> returns a zero length array,
     * access is to be denied independent of authentication state and identity.
     * Conversely, if <code>value</code> returns <code>PERMIT</code>, it
     * indicates that access is to be allowed independent of authentication
     * state and identity. When the array contains the names of one or more
     * roles, it indicates that access is contingent on membership in at
     * least one of the named roles (independent of the
     * <code>EmptyRoleSemantic</code> returned by the <code>value</code> method).
     */
    String[] rolesAllowed() default {};
}