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Java example source code file (RemoveProvider.java)

This example Java source code file (RemoveProvider.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

cipher, collection, digest, entryset, exception, expected, iterator, myprovider, object, provider, providerssnapshot, security, set, signature, unsupportedoperationexception, util

The RemoveProvider.java Java example source code

/*
 * Copyright (c) 1998, 2011, 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.
 *
 * 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.
 */

/*
 * @test
 * @bug 4190873 7054918
 * @library ../testlibrary
 * @summary Make sure provider instance can be removed from list of registered
 * providers, and "entrySet", "keySet", and "values" methods don't loop
 * indefinitely.
 */
import java.security.*;
import java.util.*;

public class RemoveProvider {

    public static void main(String[] args) throws Exception {
        ProvidersSnapshot snapshot = ProvidersSnapshot.create();
        try {
            main0(args);
        } finally {
            snapshot.restore();
        }
    }

    public static void main0(String[] args) throws Exception {

        // Add provider 1
        Provider p1 = new MyProvider("name1",1,"");
        Security.addProvider(p1);

        // Add provider 2
        Provider p2 = new MyProvider("name2",1,"");
        Security.addProvider(p2);

        // List all providers
        System.out.println("// List all providers");
        Provider[] provs = Security.getProviders();
        for (int i=0; i<provs.length; i++)
            System.out.println(provs[i].toString());

        // Remove one provider and list all remaining providers
        System.out.println("");
        System.out.println("// Remove one provider");
        Security.removeProvider("name1");
        provs = Security.getProviders();
        for (int i=0; i<provs.length; i++)
            System.out.println(provs[i].toString());

        // Iterate over the entrySet
        System.out.println("");
        System.out.println("// Iterate over entrySet");
        Map.Entry me = null;
        Set es = p1.entrySet();
        Iterator i = es.iterator();
        while (i.hasNext()) {
            me = (Map.Entry)i.next();
            System.out.println("Key: " + (String)me.getKey());
            System.out.println("Value: " + (String)me.getValue());
        }
        // Try to modify the backing Map, and catch the expected exception
        try {
            me.setValue("name1.mac");
            throw new Exception("Expected exception not thrown");
        } catch (UnsupportedOperationException uoe) {
            System.out.println("Expected exception caught");
        }

        // Iterate over the keySet, and try to remove one (should fail)
        System.out.println("");
        System.out.println("// Iterate over keySet");
        Object o = null;
        Set ks = p1.keySet();
        i = ks.iterator();
        while (i.hasNext()) {
            o = i.next();
            System.out.println((String)o);
        }
        try {
            ks.remove(o);
            throw new Exception("Expected exception not thrown");
        } catch (UnsupportedOperationException uoe) {
        }

        // Iterate over the map values
        System.out.println("");
        System.out.println("// Iterate over values");
        Collection c = p1.values();
        i = c.iterator();
        while (i.hasNext()) {
            System.out.println((String)i.next());
        }

        // Modify provider and make sure changes are reflected in
        // existing entrySet (i.e., make sure entrySet is "live").
        // First, add entry to provider.
        System.out.println("");
        System.out.println("// Add 'Cipher' entry to provider");
        p1.put("Cipher", "name1.des");
        //  entrySet
        i = es.iterator();
        boolean found = false;
        while (i.hasNext()) {
            me = (Map.Entry)i.next();
            System.out.println("Key: " + (String)me.getKey());
            System.out.println("Value: " + (String)me.getValue());
            if (((String)me.getKey()).equals("Cipher"))
                found = true;
        }
        if (!found)
            throw new Exception("EntrySet not live");
        // keySet
        i = ks.iterator();
        while (i.hasNext()) {
            o = i.next();
            System.out.println((String)o);
        }
        // collection
        i = c.iterator();
        while (i.hasNext()) {
            System.out.println((String)i.next());
        }

        // Remove entry from provider
        System.out.println("");
        System.out.println("// Remove 'Digest' entry from provider");
        p1.remove("Digest");
        // entrySet
        i = es.iterator();
        while (i.hasNext()) {
            me = (Map.Entry)i.next();
            System.out.println("Key: " + (String)me.getKey());
            System.out.println("Value: " + (String)me.getValue());
        }
        // keySet
        i = ks.iterator();
        while (i.hasNext()) {
            o = i.next();
            System.out.println((String)o);
        }
        // collection
        i = c.iterator();
        while (i.hasNext()) {
            System.out.println((String)i.next());
        }

        // Retrieve new entrySet and make sure the backing Map cannot be
        // mofified
        es = p1.entrySet();
        i = es.iterator();
        while (i.hasNext()) {
            me = (Map.Entry)i.next();
            System.out.println("Key: " + (String)me.getKey());
            System.out.println("Value: " + (String)me.getValue());
        }
        try {
            me.setValue("name1.mac");
            throw new Exception("Expected exception not thrown");
        } catch (UnsupportedOperationException uoe) {
            System.out.println("Expected exception caught");
        }
    }
}

class MyProvider extends Provider {
    public MyProvider(String name, double version, String info) {
        super(name, version, info);
        put("Signature", name+".signature");
        put("Digest", name+".digest");
    }
}

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