/*+
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 * Copyright (c) 1998, 2010, Oracle and/or its affiliates. All rights reserved.+
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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.+
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 *+
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 * This code is free software; you can redistribute it and/or modify it+
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 * under the terms of the GNU General Public License version 2 only, as+
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 * published by the Free Software Foundation.  Oracle designates this+
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 * particular file as subject to the "Classpath" exception as provided+
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 * by Oracle in the LICENSE file that accompanied this code.+
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 *+
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 * This code is distributed in the hope that it will be useful, but WITHOUT+
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 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or+
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 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License+
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 * version 2 for more details (a copy is included in the LICENSE file that+
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 * accompanied this code).+
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 *+
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 * You should have received a copy of the GNU General Public License version+
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 * 2 along with this work; if not, write to the Free Software Foundation,+
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 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.+
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 *+
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 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA+
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 * or visit www.oracle.com if you need additional information or have any+
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 * questions.+
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 */+
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+
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package sun.net;+
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+
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import java.security.PrivilegedAction;+
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import java.security.Security;+
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+
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public final class InetAddressCachePolicy {+
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+
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    // Controls the cache policy for successful lookups only+
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    private static final String cachePolicyProp = "networkaddress.cache.ttl";+
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    private static final String cachePolicyPropFallback =+
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        "sun.net.inetaddr.ttl";+
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+
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    // Controls the cache policy for negative lookups only+
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    private static final String negativeCachePolicyProp =+
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        "networkaddress.cache.negative.ttl";+
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    private static final String negativeCachePolicyPropFallback =+
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        "sun.net.inetaddr.negative.ttl";+
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+
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    public static final int FOREVER = -1;+
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    public static final int NEVER = 0;+
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+
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    /* default value for positive lookups */+
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    public static final int DEFAULT_POSITIVE = 30;+
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+
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    /* The Java-level namelookup cache policy for successful lookups:+
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     *+
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     * -1: caching forever+
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     * any positive value: the number of seconds to cache an address for+
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     *+
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     * default value is forever (FOREVER), as we let the platform do the+
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     * caching. For security reasons, this caching is made forever when+
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     * a security manager is set.+
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     */+
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    private static int cachePolicy = FOREVER;+
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+
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    /* The Java-level namelookup cache policy for negative lookups:+
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     *+
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     * -1: caching forever+
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     * any positive value: the number of seconds to cache an address for+
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     *+
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     * default value is 0. It can be set to some other value for+
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     * performance reasons.+
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     */+
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    private static int negativeCachePolicy = NEVER;+
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+
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    /*+
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     * Whether or not the cache policy for successful lookups was set+
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     * using a property (cmd line).+
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     */+
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    private static boolean propertySet;+
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+
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    /*+
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     * Whether or not the cache policy for negative lookups was set+
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     * using a property (cmd line).+
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     */+
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    private static boolean propertyNegativeSet;+
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+
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    /*+
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     * Initialize+
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     */+
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    static {+
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        Integer tmp = null;+
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+
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        try {+
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            tmp = new Integer(+
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              java.security.AccessController.doPrivileged (+
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                new PrivilegedAction<String>() {+
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                  public String run() {+
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                      return Security.getProperty(cachePolicyProp);+
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                  }+
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              }));+
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        } catch (NumberFormatException e) {+
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            // ignore+
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        }+
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        if (tmp != null) {+
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            cachePolicy = tmp.intValue();+
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            if (cachePolicy < 0) {+
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                cachePolicy = FOREVER;+
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            }+
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            propertySet = true;+
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        } else {+
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            tmp = java.security.AccessController.doPrivileged+
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                (new sun.security.action.GetIntegerAction(cachePolicyPropFallback));+
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            if (tmp != null) {+
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                cachePolicy = tmp.intValue();+
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                if (cachePolicy < 0) {+
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                    cachePolicy = FOREVER;+
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                }+
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                propertySet = true;+
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            } else {+
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                /* No properties defined for positive caching. If there is no+
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                 * security manager then use the default positive cache value.+
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                 */+
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                if (System.getSecurityManager() == null) {+
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                    cachePolicy = DEFAULT_POSITIVE;+
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                }+
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            }+
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        }+
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+
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        try {+
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            tmp = new Integer(+
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              java.security.AccessController.doPrivileged (+
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                new PrivilegedAction<String>() {+
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                  public String run() {+
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                      return Security.getProperty(negativeCachePolicyProp);+
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                  }+
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              }));+
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        } catch (NumberFormatException e) {+
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            // ignore+
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        }+
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+
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        if (tmp != null) {+
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            negativeCachePolicy = tmp.intValue();+
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            if (negativeCachePolicy < 0) {+
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                negativeCachePolicy = FOREVER;+
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            }+
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            propertyNegativeSet = true;+
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        } else {+
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            tmp = java.security.AccessController.doPrivileged+
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                (new sun.security.action.GetIntegerAction(negativeCachePolicyPropFallback));+
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            if (tmp != null) {+
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                negativeCachePolicy = tmp.intValue();+
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                if (negativeCachePolicy < 0) {+
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                    negativeCachePolicy = FOREVER;+
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                }+
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                propertyNegativeSet = true;+
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            }+
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        }+
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    }+
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+
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    public static synchronized int get() {+
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        return cachePolicy;+
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    }+
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+
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    public static synchronized int getNegative() {+
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        return negativeCachePolicy;+
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    }+
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+
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    /**+
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     * Sets the cache policy for successful lookups if the user has not+
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     * already specified a cache policy for it using a+
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     * command-property.+
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     * @param newPolicy the value in seconds for how long the lookup+
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     * should be cached+
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     */+
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    public static synchronized void setIfNotSet(int newPolicy) {+
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        /*+
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         * When setting the new value we may want to signal that the+
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         * cache should be flushed, though this doesn't seem strictly+
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         * necessary.+
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         */+
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        if (!propertySet) {+
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            checkValue(newPolicy, cachePolicy);+
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            cachePolicy = newPolicy;+
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        }+
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    }+
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+
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    /**+
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     * Sets the cache policy for negative lookups if the user has not+
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     * already specified a cache policy for it using a+
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     * command-property.+
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     * @param newPolicy the value in seconds for how long the lookup+
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     * should be cached+
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     */+
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    public static synchronized void setNegativeIfNotSet(int newPolicy) {+
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        /*+
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         * When setting the new value we may want to signal that the+
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         * cache should be flushed, though this doesn't seem strictly+
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         * necessary.+
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         */+
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        if (!propertyNegativeSet) {+
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            // Negative caching does not seem to have any security+
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            // implications.+
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            // checkValue(newPolicy, negativeCachePolicy);+
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            negativeCachePolicy = newPolicy;+
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        }+
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    }+
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+
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    private static void checkValue(int newPolicy, int oldPolicy) {+
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        /*+
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         * If malicious code gets a hold of this method, prevent+
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         * setting the cache policy to something laxer or some+
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         * invalid negative value.+
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         */+
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        if (newPolicy == FOREVER)+
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            return;+
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+
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        if ((oldPolicy == FOREVER) ||+
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            (newPolicy < oldPolicy) ||+
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            (newPolicy < FOREVER)) {+
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+
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            throw new+
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                SecurityException("can't make InetAddress cache more lax");+
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        }+
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    }+
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}+
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