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 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
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package java.security;

/**
 * This class defines the <i>Service Provider Interface</i> (<b>SPI</b>)
 * for the {@code Policy} class.
 * All the abstract methods in this class must be implemented by each
 * service provider who wishes to supply a Policy implementation.
 *
 * <p> Subclass implementations of this abstract class must provide
 * a public constructor that takes a {@code Policy.Parameters}
 * object as an input parameter. This constructor also must throw
 * an IllegalArgumentException if it does not understand the
 * {@code Policy.Parameters} input.
 *
 *
 * @since 1.6
 */

public abstract class PolicySpi {

 /**
 * Check whether the policy has granted a Permission to a ProtectionDomain.
 *
 * @param domain the ProtectionDomain to check.
 *
 * @param permission check whether this permission is granted to the
 * specified domain.
 *
 * @return boolean true if the permission is granted to the domain.
 */
 protected abstract boolean engineImplies
 (ProtectionDomain domain, Permission permission);

 /**
 * Refreshes/reloads the policy configuration. The behavior of this method
 * depends on the implementation. For example, calling {@code refresh}
 * on a file-based policy will cause the file to be re-read.
 *
 * <p> The default implementation of this method does nothing.
 * This method should be overridden if a refresh operation is supported
 * by the policy implementation.
 */
 protected void engineRefresh() { }

 /**
 * Return a PermissionCollection object containing the set of
 * permissions granted to the specified CodeSource.
 *
 * <p> The default implementation of this method returns
 * Policy.UNSUPPORTED_EMPTY_COLLECTION object. This method can be
 * overridden if the policy implementation can return a set of
 * permissions granted to a CodeSource.
 *
 * @param codesource the CodeSource to which the returned
 * PermissionCollection has been granted.
 *
 * @return a set of permissions granted to the specified CodeSource.
 * If this operation is supported, the returned
 * set of permissions must be a new mutable instance
 * and it must support heterogeneous Permission types.
 * If this operation is not supported,
 * Policy.UNSUPPORTED_EMPTY_COLLECTION is returned.
 */
 protected PermissionCollection engineGetPermissions
 (CodeSource codesource) {
 return Policy.UNSUPPORTED_EMPTY_COLLECTION;
 }

 /**
 * Return a PermissionCollection object containing the set of
 * permissions granted to the specified ProtectionDomain.
 *
 * <p> The default implementation of this method returns
 * Policy.UNSUPPORTED_EMPTY_COLLECTION object. This method can be
 * overridden if the policy implementation can return a set of
 * permissions granted to a ProtectionDomain.
 *
 * @param domain the ProtectionDomain to which the returned
 * PermissionCollection has been granted.
 *
 * @return a set of permissions granted to the specified ProtectionDomain.
 * If this operation is supported, the returned
 * set of permissions must be a new mutable instance
 * and it must support heterogeneous Permission types.
 * If this operation is not supported,
 * Policy.UNSUPPORTED_EMPTY_COLLECTION is returned.
 */
 protected PermissionCollection engineGetPermissions
 (ProtectionDomain domain) {
 return Policy.UNSUPPORTED_EMPTY_COLLECTION;
 }
}