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	/*
	* Copyright (c) 1997, 2017, Oracle and/or its affiliates. All rights reserved.
	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
	*
	* This code is free software; you can redistribute it and/or modify it
	* under the terms of the GNU General Public License version 2 only, as
	* published by the Free Software Foundation. Oracle designates this
	* particular file as subject to the "Classpath" exception as provided
	* by Oracle in the LICENSE file that accompanied this code.
	*
	* This code is distributed in the hope that it will be useful, but WITHOUT
	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
	* version 2 for more details (a copy is included in the LICENSE file that
	* accompanied this code).
	*
	* You should have received a copy of the GNU General Public License version
	* 2 along with this work; if not, write to the Free Software Foundation,
	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
	*
	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
	* or visit www.oracle.com if you need additional information or have any
	* questions.
	*/


	package java.security;

	import java.util.Enumeration;
	import java.util.WeakHashMap;
	import java.util.Objects;
	import sun.security.jca.GetInstance;
	import sun.security.util.Debug;
	import sun.security.util.SecurityConstants;


	/**
	* A Policy object is responsible for determining whether code executing
	* in the Java runtime environment has permission to perform a
	* security-sensitive operation.
	*
	* <p> There is only one Policy object installed in the runtime at any
	* given time. A Policy object can be installed by calling the
	* {@code setPolicy} method. The installed Policy object can be
	* obtained by calling the {@code getPolicy} method.
	*
	* <p> If no Policy object has been installed in the runtime, a call to
	* {@code getPolicy} installs an instance of the default Policy
	* implementation (a default subclass implementation of this abstract class).
	* The default Policy implementation can be changed by setting the value
	* of the {@code policy.provider} security property to the fully qualified
	* name of the desired Policy subclass implementation. The system class loader
	* is used to load this class.
	*
	* <p> Application code can directly subclass Policy to provide a custom
	* implementation. In addition, an instance of a Policy object can be
	* constructed by invoking one of the {@code getInstance} factory methods
	* with a standard type. The default policy type is "JavaPolicy".
	*
	* <p> Once a Policy instance has been installed (either by default, or by
	* calling {@code setPolicy}), the Java runtime invokes its
	* {@code implies} method when it needs to
	* determine whether executing code (encapsulated in a ProtectionDomain)
	* can perform SecurityManager-protected operations. How a Policy object
	* retrieves its policy data is up to the Policy implementation itself.
	* The policy data may be stored, for example, in a flat ASCII file,
	* in a serialized binary file of the Policy class, or in a database.
	*
	* <p> The {@code refresh} method causes the policy object to
	* refresh/reload its data. This operation is implementation-dependent.
	* For example, if the policy object stores its data in configuration files,
	* calling {@code refresh} will cause it to re-read the configuration
	* policy files. If a refresh operation is not supported, this method does
	* nothing. Note that refreshed policy may not have an effect on classes
	* in a particular ProtectionDomain. This is dependent on the Policy
	* provider's implementation of the {@code implies}
	* method and its PermissionCollection caching strategy.
	*
	* @author Roland Schemers
	* @author Gary Ellison
	* @since 1.2
	* @see java.security.Provider
	* @see java.security.ProtectionDomain
	* @see java.security.Permission
	* @see java.security.Security security properties
	*/

	public abstract class Policy {

	/**
	* A read-only empty PermissionCollection instance.
	* @since 1.6
	*/
	public static final PermissionCollection UNSUPPORTED_EMPTY_COLLECTION =
	new UnsupportedEmptyCollection();

	// Information about the system-wide policy.
	private static class PolicyInfo {
	// the system-wide policy
	final Policy policy;
	// a flag indicating if the system-wide policy has been initialized
	final boolean initialized;

	PolicyInfo(Policy policy, boolean initialized) {
	this.policy = policy;
	this.initialized = initialized;
	}
	}

	// PolicyInfo is volatile since we apply DCL during initialization.
	// For correctness, care must be taken to read the field only once and only
	// write to it after any other initialization action has taken place.
	private static volatile PolicyInfo policyInfo = new PolicyInfo(null, false);

	private static final Debug debug = Debug.getInstance("policy");

	// Default policy provider
	private static final String DEFAULT_POLICY =
	"sun.security.provider.PolicyFile";

	// Cache mapping ProtectionDomain.Key to PermissionCollection
	private WeakHashMap<ProtectionDomain.Key, PermissionCollection> pdMapping;

	/** package private for AccessControlContext and ProtectionDomain */
	static boolean isSet() {
	PolicyInfo pi = policyInfo;
	return pi.policy != null && pi.initialized == true;
	}

	private static void checkPermission(String type) {
	SecurityManager sm = System.getSecurityManager();
	if (sm != null) {
	sm.checkPermission(new SecurityPermission("createPolicy." + type));
	}
	}

	/**
	* Returns the installed Policy object. This value should not be cached,
	* as it may be changed by a call to {@code setPolicy}.
	* This method first calls
	* {@code SecurityManager.checkPermission} with a
	* {@code SecurityPermission("getPolicy")} permission
	* to ensure it's ok to get the Policy object.
	*
	* @return the installed Policy.
	*
	* @throws SecurityException
	* if a security manager exists and its
	* {@code checkPermission} method doesn't allow
	* getting the Policy object.
	*
	* @see SecurityManager#checkPermission(Permission)
	* @see #setPolicy(java.security.Policy)
	*/
	public static Policy getPolicy()
	{
	SecurityManager sm = System.getSecurityManager();
	if (sm != null)
	sm.checkPermission(SecurityConstants.GET_POLICY_PERMISSION);
	return getPolicyNoCheck();
	}

	/**
	* Returns the installed Policy object, skipping the security check.
	* Used by ProtectionDomain and getPolicy.
	*
	* @return the installed Policy.
	*/
	static Policy getPolicyNoCheck()
	{
	PolicyInfo pi = policyInfo;
	// Use double-check idiom to avoid locking if system-wide policy is
	// already initialized
	if (pi.initialized == false \|\| pi.policy == null) {
	synchronized (Policy.class) {
	pi = policyInfo;
	if (pi.policy == null) {
	return loadPolicyProvider();
	}
	}
	}
	return pi.policy;
	}

	/**
	* Loads and instantiates a Policy implementation specified by the
	* policy.provider security property. Note that this method should only
	* be called by getPolicyNoCheck and from within a synchronized block with
	* an intrinsic lock on the Policy.class.
	*/
	private static Policy loadPolicyProvider() {
	String policyProvider =
	AccessController.doPrivileged(new PrivilegedAction<>() {
	@Override
	public String run() {
	return Security.getProperty("policy.provider");
	}
	});

	/*
	* If policy.provider is not set or is set to the default provider,
	* simply instantiate it and return.
	*/
	if (policyProvider == null \|\| policyProvider.isEmpty() \|\|
	policyProvider.equals(DEFAULT_POLICY))
	{
	Policy polFile = new sun.security.provider.PolicyFile();
	policyInfo = new PolicyInfo(polFile, true);
	return polFile;
	}

	/*
	* Locate, load, and instantiate the policy.provider impl using
	* the system class loader. While doing so, install the bootstrap
	* provider to avoid potential recursion.
	*/
	Policy polFile = new sun.security.provider.PolicyFile();
	policyInfo = new PolicyInfo(polFile, false);

	Policy pol = AccessController.doPrivileged(new PrivilegedAction<>() {
	@Override
	public Policy run() {
	try {
	ClassLoader scl = ClassLoader.getSystemClassLoader();
	@SuppressWarnings("deprecation")
	Object o = Class.forName(policyProvider, true, scl).newInstance();
	return (Policy)o;
	} catch (Exception e) {
	if (debug != null) {
	debug.println("policy provider " + policyProvider +
	" not available");
	e.printStackTrace();
	}
	return null;
	}
	}
	});

	if (pol == null) {
	// Fallback and use the system default implementation
	if (debug != null) {
	debug.println("using " + DEFAULT_POLICY);
	}
	pol = polFile;
	}
	policyInfo = new PolicyInfo(pol, true);
	return pol;
	}

	/**
	* Sets the system-wide Policy object. This method first calls
	* {@code SecurityManager.checkPermission} with a
	* {@code SecurityPermission("setPolicy")}
	* permission to ensure it's ok to set the Policy.
	*
	* @param p the new system Policy object.
	*
	* @throws SecurityException
	* if a security manager exists and its
	* {@code checkPermission} method doesn't allow
	* setting the Policy.
	*
	* @see SecurityManager#checkPermission(Permission)
	* @see #getPolicy()
	*
	*/
	public static void setPolicy(Policy p)
	{
	SecurityManager sm = System.getSecurityManager();
	if (sm != null) sm.checkPermission(
	new SecurityPermission("setPolicy"));
	if (p != null) {
	initPolicy(p);
	}
	synchronized (Policy.class) {
	policyInfo = new PolicyInfo(p, p != null);
	}
	}

	/**
	* Initialize superclass state such that a legacy provider can
	* handle queries for itself.
	*
	* @since 1.4
	*/
	private static void initPolicy (final Policy p) {
	/*
	* A policy provider not on the bootclasspath could trigger
	* security checks fulfilling a call to either Policy.implies
	* or Policy.getPermissions. If this does occur the provider
	* must be able to answer for it's own ProtectionDomain
	* without triggering additional security checks, otherwise
	* the policy implementation will end up in an infinite
	* recursion.
	*
	* To mitigate this, the provider can collect it's own
	* ProtectionDomain and associate a PermissionCollection while
	* it is being installed. The currently installed policy
	* provider (if there is one) will handle calls to
	* Policy.implies or Policy.getPermissions during this
	* process.
	*
	* This Policy superclass caches away the ProtectionDomain and
	* statically binds permissions so that legacy Policy
	* implementations will continue to function.
	*/

	ProtectionDomain policyDomain =
	AccessController.doPrivileged(new PrivilegedAction<>() {
	public ProtectionDomain run() {
	return p.getClass().getProtectionDomain();
	}
	});

	/*
	* Collect the permissions granted to this protection domain
	* so that the provider can be security checked while processing
	* calls to Policy.implies or Policy.getPermissions.
	*/
	PermissionCollection policyPerms = null;
	synchronized (p) {
	if (p.pdMapping == null) {
	p.pdMapping = new WeakHashMap<>();
	}
	}

	if (policyDomain.getCodeSource() != null) {
	Policy pol = policyInfo.policy;
	if (pol != null) {
	policyPerms = pol.getPermissions(policyDomain);
	}

	if (policyPerms == null) { // assume it has all
	policyPerms = new Permissions();
	policyPerms.add(SecurityConstants.ALL_PERMISSION);
	}

	synchronized (p.pdMapping) {
	// cache of pd to permissions
	p.pdMapping.put(policyDomain.key, policyPerms);
	}
	}
	return;
	}


	/**
	* Returns a Policy object of the specified type.
	*
	* <p> This method traverses the list of registered security providers,
	* starting with the most preferred Provider.
	* A new Policy object encapsulating the
	* PolicySpi implementation from the first
	* Provider that supports the specified type is returned.
	*
	* <p> Note that the list of registered providers may be retrieved via
	* the {@link Security#getProviders() Security.getProviders()} method.
	*
	* @implNote
	* The JDK Reference Implementation additionally uses the
	* {@code jdk.security.provider.preferred}
	* {@link Security#getProperty(String) Security} property to determine
	* the preferred provider order for the specified algorithm. This
	* may be different than the order of providers returned by
	* {@link Security#getProviders() Security.getProviders()}.
	*
	* @param type the specified Policy type. See the Policy section in the
	* <a href=
	* "{@docRoot}/../specs/security/standard-names.html#policy-types">
	* Java Security Standard Algorithm Names Specification</a>
	* for a list of standard Policy types.
	*
	* @param params parameters for the Policy, which may be null.
	*
	* @return the new {@code Policy} object
	*
	* @throws IllegalArgumentException if the specified parameters
	* are not understood by the {@code PolicySpi} implementation
	* from the selected {@code Provider}
	*
	* @throws NoSuchAlgorithmException if no {@code Provider} supports
	* a {@code PolicySpi} implementation for the specified type
	*
	* @throws NullPointerException if {@code type} is {@code null}
	*
	* @throws SecurityException if the caller does not have permission
	* to get a {@code Policy} instance for the specified type.
	*
	* @see Provider
	* @since 1.6
	*/
	public static Policy getInstance(String type, Policy.Parameters params)
	throws NoSuchAlgorithmException {
	Objects.requireNonNull(type, "null type name");
	checkPermission(type);
	try {
	GetInstance.Instance instance = GetInstance.getInstance("Policy",
	PolicySpi.class,
	type,
	params);
	return new PolicyDelegate((PolicySpi)instance.impl,
	instance.provider,
	type,
	params);
	} catch (NoSuchAlgorithmException nsae) {
	return handleException(nsae);
	}
	}

	/**
	* Returns a Policy object of the specified type.
	*
	* <p> A new Policy object encapsulating the
	* PolicySpi implementation from the specified provider
	* is returned. The specified provider must be registered
	* in the provider list.
	*
	* <p> Note that the list of registered providers may be retrieved via
	* the {@link Security#getProviders() Security.getProviders()} method.
	*
	* @param type the specified Policy type. See the Policy section in the
	* <a href=
	* "{@docRoot}/../specs/security/standard-names.html#policy-types">
	* Java Security Standard Algorithm Names Specification</a>
	* for a list of standard Policy types.
	*
	* @param params parameters for the Policy, which may be null.
	*
	* @param provider the provider.
	*
	* @return the new {@code Policy} object
	*
	* @throws IllegalArgumentException if the specified provider
	* is {@code null} or empty, or if the specified parameters are
	* not understood by the {@code PolicySpi} implementation from
	* the specified provider
	*
	* @throws NoSuchAlgorithmException if the specified provider does not
	* support a {@code PolicySpi} implementation for the specified
	* type
	*
	* @throws NoSuchProviderException if the specified provider is not
	* registered in the security provider list
	*
	* @throws NullPointerException if {@code type} is {@code null}
	*
	* @throws SecurityException if the caller does not have permission
	* to get a {@code Policy} instance for the specified type
	*
	* @see Provider
	* @since 1.6
	*/
	public static Policy getInstance(String type,
	Policy.Parameters params,
	String provider)
	throws NoSuchProviderException, NoSuchAlgorithmException {

	Objects.requireNonNull(type, "null type name");
	if (provider == null \|\| provider.length() == 0) {
	throw new IllegalArgumentException("missing provider");
	}

	checkPermission(type);
	try {
	GetInstance.Instance instance = GetInstance.getInstance("Policy",
	PolicySpi.class,
	type,
	params,
	provider);
	return new PolicyDelegate((PolicySpi)instance.impl,
	instance.provider,
	type,
	params);
	} catch (NoSuchAlgorithmException nsae) {
	return handleException(nsae);
	}
	}

	/**
	* Returns a Policy object of the specified type.
	*
	* <p> A new Policy object encapsulating the
	* PolicySpi implementation from the specified Provider
	* object is returned. Note that the specified Provider object
	* does not have to be registered in the provider list.
	*
	* @param type the specified Policy type. See the Policy section in the
	* <a href=
	* "{@docRoot}/../specs/security/standard-names.html#policy-types">
	* Java Security Standard Algorithm Names Specification</a>
	* for a list of standard Policy types.
	*
	* @param params parameters for the Policy, which may be null.
	*
	* @param provider the Provider.
	*
	* @return the new {@code Policy} object
	*
	* @throws IllegalArgumentException if the specified {@code Provider}
	* is {@code null}, or if the specified parameters are not
	* understood by the {@code PolicySpi} implementation from the
	* specified {@code Provider}
	*
	* @throws NoSuchAlgorithmException if the specified {@code Provider}
	* does not support a {@code PolicySpi} implementation for
	* the specified type
	*
	* @throws NullPointerException if {@code type} is {@code null}
	*
	* @throws SecurityException if the caller does not have permission
	* to get a {@code Policy} instance for the specified type
	*
	* @see Provider
	* @since 1.6
	*/
	public static Policy getInstance(String type,
	Policy.Parameters params,
	Provider provider)
	throws NoSuchAlgorithmException {

	Objects.requireNonNull(type, "null type name");
	if (provider == null) {
	throw new IllegalArgumentException("missing provider");
	}

	checkPermission(type);
	try {
	GetInstance.Instance instance = GetInstance.getInstance("Policy",
	PolicySpi.class,
	type,
	params,
	provider);
	return new PolicyDelegate((PolicySpi)instance.impl,
	instance.provider,
	type,
	params);
	} catch (NoSuchAlgorithmException nsae) {
	return handleException(nsae);
	}
	}

	private static Policy handleException(NoSuchAlgorithmException nsae)
	throws NoSuchAlgorithmException {
	Throwable cause = nsae.getCause();
	if (cause instanceof IllegalArgumentException) {
	throw (IllegalArgumentException)cause;
	}
	throw nsae;
	}

	/**
	* Return the Provider of this Policy.
	*
	* <p> This Policy instance will only have a Provider if it
	* was obtained via a call to {@code Policy.getInstance}.
	* Otherwise this method returns null.
	*
	* @return the Provider of this Policy, or null.
	*
	* @since 1.6
	*/
	public Provider getProvider() {
	return null;
	}

	/**
	* Return the type of this Policy.
	*
	* <p> This Policy instance will only have a type if it
	* was obtained via a call to {@code Policy.getInstance}.
	* Otherwise this method returns null.
	*
	* @return the type of this Policy, or null.
	*
	* @since 1.6
	*/
	public String getType() {
	return null;
	}

	/**
	* Return Policy parameters.
	*
	* <p> This Policy instance will only have parameters if it
	* was obtained via a call to {@code Policy.getInstance}.
	* Otherwise this method returns null.
	*
	* @return Policy parameters, or null.
	*
	* @since 1.6
	*/
	public Policy.Parameters getParameters() {
	return null;
	}

	/**
	* Return a PermissionCollection object containing the set of
	* permissions granted to the specified CodeSource.
	*
	* <p> Applications are discouraged from calling this method
	* since this operation may not be supported by all policy implementations.
	* Applications should solely rely on the {@code implies} method
	* to perform policy checks. If an application absolutely must call
	* a getPermissions method, it should call
	* {@code getPermissions(ProtectionDomain)}.
	*
	* <p> The default implementation of this method returns
	* Policy.UNSUPPORTED_EMPTY_COLLECTION. 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.
	*/
	public PermissionCollection getPermissions(CodeSource codesource) {
	return Policy.UNSUPPORTED_EMPTY_COLLECTION;
	}

	/**
	* Return a PermissionCollection object containing the set of
	* permissions granted to the specified ProtectionDomain.
	*
	* <p> Applications are discouraged from calling this method
	* since this operation may not be supported by all policy implementations.
	* Applications should rely on the {@code implies} method
	* to perform policy checks.
	*
	* <p> The default implementation of this method first retrieves
	* the permissions returned via {@code getPermissions(CodeSource)}
	* (the CodeSource is taken from the specified ProtectionDomain),
	* as well as the permissions located inside the specified ProtectionDomain.
	* All of these permissions are then combined and returned in a new
	* PermissionCollection object. If {@code getPermissions(CodeSource)}
	* returns Policy.UNSUPPORTED_EMPTY_COLLECTION, then this method
	* returns the permissions contained inside the specified ProtectionDomain
	* in a new PermissionCollection object.
	*
	* <p> This method can be overridden if the policy implementation
	* supports returning 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.
	*
	* @since 1.4
	*/
	public PermissionCollection getPermissions(ProtectionDomain domain) {
	PermissionCollection pc = null;

	if (domain == null)
	return new Permissions();

	if (pdMapping == null) {
	initPolicy(this);
	}

	synchronized (pdMapping) {
	pc = pdMapping.get(domain.key);
	}

	if (pc != null) {
	Permissions perms = new Permissions();
	synchronized (pc) {
	for (Enumeration<Permission> e = pc.elements() ; e.hasMoreElements() ;) {
	perms.add(e.nextElement());
	}
	}
	return perms;
	}

	pc = getPermissions(domain.getCodeSource());
	if (pc == null \|\| pc == UNSUPPORTED_EMPTY_COLLECTION) {
	pc = new Permissions();
	}

	addStaticPerms(pc, domain.getPermissions());
	return pc;
	}

	/**
	* add static permissions to provided permission collection
	*/
	private void addStaticPerms(PermissionCollection perms,
	PermissionCollection statics) {
	if (statics != null) {
	synchronized (statics) {
	Enumeration<Permission> e = statics.elements();
	while (e.hasMoreElements()) {
	perms.add(e.nextElement());
	}
	}
	}
	}

	/**
	* Evaluates the global policy for the permissions granted to
	* the ProtectionDomain and tests whether the permission is
	* granted.
	*
	* @param domain the ProtectionDomain to test
	* @param permission the Permission object to be tested for implication.
	*
	* @return true if "permission" is a proper subset of a permission
	* granted to this ProtectionDomain.
	*
	* @see java.security.ProtectionDomain
	* @since 1.4
	*/
	public boolean implies(ProtectionDomain domain, Permission permission) {
	PermissionCollection pc;

	if (pdMapping == null) {
	initPolicy(this);
	}

	synchronized (pdMapping) {
	pc = pdMapping.get(domain.key);
	}

	if (pc != null) {
	return pc.implies(permission);
	}

	pc = getPermissions(domain);
	if (pc == null) {
	return false;
	}

	synchronized (pdMapping) {
	// cache it
	pdMapping.put(domain.key, pc);
	}

	return pc.implies(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.
	*/
	public void refresh() { }

	/**
	* This subclass is returned by the getInstance calls. All Policy calls
	* are delegated to the underlying PolicySpi.
	*/
	private static class PolicyDelegate extends Policy {

	private PolicySpi spi;
	private Provider p;
	private String type;
	private Policy.Parameters params;

	private PolicyDelegate(PolicySpi spi, Provider p,
	String type, Policy.Parameters params) {
	this.spi = spi;
	this.p = p;
	this.type = type;
	this.params = params;
	}

	@Override public String getType() { return type; }

	@Override public Policy.Parameters getParameters() { return params; }

	@Override public Provider getProvider() { return p; }

	@Override
	public PermissionCollection getPermissions(CodeSource codesource) {
	return spi.engineGetPermissions(codesource);
	}
	@Override
	public PermissionCollection getPermissions(ProtectionDomain domain) {
	return spi.engineGetPermissions(domain);
	}
	@Override
	public boolean implies(ProtectionDomain domain, Permission perm) {
	return spi.engineImplies(domain, perm);
	}
	@Override
	public void refresh() {
	spi.engineRefresh();
	}
	}

	/**
	* This represents a marker interface for Policy parameters.
	*
	* @since 1.6
	*/
	public static interface Parameters { }

	/**
	* This class represents a read-only empty PermissionCollection object that
	* is returned from the {@code getPermissions(CodeSource)} and
	* {@code getPermissions(ProtectionDomain)}
	* methods in the Policy class when those operations are not
	* supported by the Policy implementation.
	*/
	private static class UnsupportedEmptyCollection
	extends PermissionCollection {

	private static final long serialVersionUID = -8492269157353014774L;

	private Permissions perms;

	/**
	* Create a read-only empty PermissionCollection object.
	*/
	public UnsupportedEmptyCollection() {
	this.perms = new Permissions();
	perms.setReadOnly();
	}

	/**
	* Adds a permission object to the current collection of permission
	* objects.
	*
	* @param permission the Permission object to add.
	*
	* @exception SecurityException - if this PermissionCollection object
	* has been marked readonly
	*/
	@Override public void add(Permission permission) {
	perms.add(permission);
	}

	/**
	* Checks to see if the specified permission is implied by the
	* collection of Permission objects held in this PermissionCollection.
	*
	* @param permission the Permission object to compare.
	*
	* @return true if "permission" is implied by the permissions in
	* the collection, false if not.
	*/
	@Override public boolean implies(Permission permission) {
	return perms.implies(permission);
	}

	/**
	* Returns an enumeration of all the Permission objects in the
	* collection.
	*
	* @return an enumeration of all the Permissions.
	*/
	@Override public Enumeration<Permission> elements() {
	return perms.elements();
	}
	}
	}

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