security.java

This is a resource based on j2me embedded,if you dont understand,you can connection with me .

     * provider) mapping the key, if any.
     * The order in which the providers are looked up is the
     * provider-preference order, as specificed in the security
     * properties file.
     */
    private static ProviderProperty getProviderProperty(String key) {
	ProviderProperty entry
	    = (ProviderProperty)providerPropertiesCache.get(key);
	if (entry != null) {
	    return entry;
	}

	for (int i = 0; i < providers.size(); i++) {

	    String matchKey = null;
	    Provider prov = (Provider)providers.elementAt(i);	    
	    String prop = prov.getProperty(key);

	    if (prop == null) {
		// Is there a match if we do a case-insensitive property name
		// comparison? Let's try ...
		for (Enumeration enum_ = prov.keys();
		     enum_.hasMoreElements() && prop==null; ) {
		    matchKey = (String)enum_.nextElement();
		    if (key.equalsIgnoreCase(matchKey)) {
			prop = prov.getProperty(matchKey);
			break;
		    }
		}
	    }

	    if (prop != null) {
		ProviderProperty newEntry = new ProviderProperty();
		newEntry.className = prop;
		newEntry.provider = prov;
		providerPropertiesCache.put(key, newEntry);
		if (matchKey != null) {
		    // Store the property value in the cache under the exact
		    // property name, as specified by the provider
		    providerPropertiesCache.put(matchKey, newEntry);
		}
		return newEntry;
	    }
	}

	return entry;
    }

    /**
     * Returns the property (if any) mapping the key for the given provider.
     */
    private static String getProviderProperty(String key, Provider provider) {
	String prop = provider.getProperty(key);
	if (prop == null) {
	    // Is there a match if we do a case-insensitive property name
	    // comparison? Let's try ...
	    for (Enumeration enum_ = provider.keys();
		 enum_.hasMoreElements() && prop==null; ) {
		String matchKey = (String)enum_.nextElement();
		if (key.equalsIgnoreCase(matchKey)) {
		    prop = provider.getProperty(matchKey);
		    break;
		}
	    }
	}
	return prop;
    }

    /**
     * We always map names to standard names
     */
    private static String getStandardName(String alias, String engineType,
        Provider prov) {
	return getProviderProperty("Alg.Alias." + engineType + "." + alias,
				   prov);
    }

    /** 
     * Gets a specified property for an algorithm. The algorithm name
     * should be a standard name. See Appendix A in the <a href=
     * "../../../guide/security/CryptoSpec.html#AppA">
     * Java Cryptography Architecture API Specification &amp; Reference </a> 
     * for information about standard algorithm names.
     * One possible use is by specialized algorithm parsers, which may map 
     * classes to algorithms which they understand (much like Key parsers 
     * do).
     *
     * param algName the algorithm name.
     *
     * param propName the name of the property to get.
     * 
     * return the value of the specified property.  
     *
     * deprecated This method used to return the value of a proprietary
     * property in the master file of the "SUN" Cryptographic Service
     * Provider in order to determine how to parse algorithm-specific
     * parameters. Use the new provider-based and algorithm-independent
     * <code>AlgorithmParameters</code> and <code>KeyFactory</code> engine
     * classes (introduced in the Java 2 platform) instead.
     *
    public static String getAlgorithmProperty(String algName,
					      String propName) {
	reloadProviders();
	ProviderProperty entry = getProviderProperty("Alg." + propName
						     + "." + algName);
	if (entry != null) {
	    return entry.className;
	} else {
	    return null;
	}
    }
     */

    /*
     * Lookup the algorithm in our list of providers. Process
     * each provider in priority order one at a time looking for
     * either the direct engine property or a matching alias.
     */
    private static ProviderProperty getEngineClassName(String algName,
						       String engineType)
        throws NoSuchAlgorithmException
    {
	ProviderProperty pp;
	String key = engineType;

	if (algName != null)
	    key += "." + algName;
	pp = (ProviderProperty)engineCache.get(key);
	if (pp != null)
	    return pp;

	synchronized (Security.class) {
	    sun.misc.Launcher l = sun.misc.Launcher.getLauncher();
	    /*
	     * In case some providers have been loaded out of the
	     * priority order when the launcher l is null, we should
	     * clear the vector "providers" and reset the indexStaticProviders
	     * to zero when the launcher l isn't null.
	     *
	     * We should only do the above if the "reloadProviders" is true
	     * which means that the method reloadProviders() hasn't
	     * load all statically registered providers yet.
	     * Once the reloadProviders() method has loaded all statically
	     * registered providers, we shouldn't clear the vector
	     * "providers" in this getEngineClassName() method.
	     */
	    if ((reloadProviders == true) &&
		(l != null) && (resetProviderIndex == true)) {
		resetProviderIndex = false;
		indexStaticProviders = 0;
		providers.removeAllElements();
		providerPropertiesCache.clear();
		engineCache.clear();
		searchResultsCache.clear();
		providerLoads.clear();
	    }

	    // We should call loadOneMoreProvider() if no provider
	    // has been loaded yet. Otherwise, we may not be able to
	    // get in the following "for" loop.
	    if (providers.size() == 0) {
		loadOneMoreProvider();
	    }
	    for (int i = 0; i < providers.size(); i++) {
		Provider prov = (Provider)providers.elementAt(i);
		try {
		    pp = getEngineClassName(algName, prov,
					    engineType);
		} catch (NoSuchAlgorithmException e) {
		    if (i == providers.size() - 1) {
			// The requested algorithm may be available in
			// a registered provider which hasn't been loaded
			// yet. Let's try to load one more registered
			// provider. The method loadOneMoreProvider()
			// won't do anything if we have tried to load all
			// registered providers.
			loadOneMoreProvider();
		    }
		    continue;
		}

		/* Cache it */
		engineCache.put(key, pp);
		return pp;
	    }
	}

	throw new NoSuchAlgorithmException(algName.toUpperCase() + " " +
					   engineType + " not available");
    }


    private static ProviderProperty getEngineClassName(String algName,
						       String provider, 
						       String engineType) 
	throws NoSuchAlgorithmException, NoSuchProviderException
    {
	if (provider == null) {
	    return getEngineClassName(algName, engineType);
	}

	// check if the provider is installed
	Provider prov = getProvider(provider);
	if (prov == null) {
	    throw new NoSuchProviderException("no such provider: " +
					      provider);
	}

	return getEngineClassName(algName, prov, engineType); 
    }

    /**
     * The parameter provider cannot be null.
     */
    private static ProviderProperty getEngineClassName(String algName,
						       Provider provider, 
						       String engineType) 
	throws NoSuchAlgorithmException
    {
	String key;
	if (engineType.equalsIgnoreCase("SecureRandom") && algName == null)
	    key = engineType;
	else
	    key = engineType + "." + algName;
	
	String className = getProviderProperty(key, provider);
	if (className == null) {
	    if (engineType.equalsIgnoreCase("SecureRandom") &&
		algName == null)
		throw new NoSuchAlgorithmException
		    ("SecureRandom not available for provider " +
		     provider.getName());
	    else {
		// try algName as alias name
		String stdName = getStandardName(algName, engineType, provider);
		if (stdName != null) key = engineType + "." + stdName;
		if ((stdName == null)
		    || (className = getProviderProperty(key, provider)) == null)
		    throw new NoSuchAlgorithmException("no such algorithm: " +
						       algName
						       + " for provider " +
						       provider.getName());
	    }
	}
	
	ProviderProperty entry = new ProviderProperty();
	entry.className = className;
	entry.provider = provider;

	return entry;
    }

    /**
     * Adds a new provider, at a specified position. The position is
     * the preference order in which providers are searched for
     * requested algorithms. Note that it is not guaranteed that this
     * preference will be respected. The position is 1-based, that is,
     * 1 is most preferred, followed by 2, and so on.
     * 
     * <p>If the given provider is installed at the requested position,
     * the provider that used to be at that position, and all providers
     * with a position greater than <code>position</code>, are shifted up
     * one position (towards the end of the list of installed providers).
     * 
     * <p>A provider cannot be added if it is already installed.
     * 
     * <p>First, if there is a security manager, its
     * <code>checkSecurityAccess</code> 
     * method is called with the string
     * <code>"insertProvider."+provider.getName()</code> 
     * to see if it's ok to add a new provider. 
     * If the default implementation of <code>checkSecurityAccess</code> 
     * is used (i.e., that method is not overriden), then this will result in
     * a call to the security manager's <code>checkPermission</code> method
     * with a
     * <code>SecurityPermission("insertProvider."+provider.getName())</code>
     * permission.
     *
     * @param provider the provider to be added.
     *
     * @param position the preference position that the caller would
     * like for this provider.
     * 
     * @return the actual preference position in which the provider was 
     * added, or -1 if the provider was not added because it is
     * already installed.
     *
     * @throws  SecurityException
     *          if a security manager exists and its <code>{@link
     *          java.lang.SecurityManager#checkSecurityAccess}</code> method
     *          denies access to add a new provider
     *
     * @see #getProvider
     * @see #removeProvider 
     * @see java.security.SecurityPermission
     */
    public static synchronized int insertProviderAt(Provider provider,
						    int position) {
	reloadProviders();

	check("insertProvider."+provider.getName());

	/* First check if the provider is already installed */
	Provider already = getProvider(provider.getName());
	if (already != null) {
	    return -1;
	}	
		
	int size = providers.size();
	if (position > size || position <= 0) {
	    position = size+1;
	}

	providers.insertElementAt(provider, position-1);

	// empty provider-property cache
	providerPropertiesCache.clear();
	engineCache.clear();
	searchResultsCache.clear();
		
	return position;
    }

    /**
     * Adds a provider to the next position available.
     *
     * <p>First, if there is a security manager, its
     * <code>checkSecurityAccess</code> 
     * method is called with the string
     * <code>"insertProvider."+provider.getName()</code> 
     * to see if it's ok to add a new provider. 
     * If the default implementation of <code>checkSecurityAccess</code> 
     * is used (i.e., that method is not overriden), then this will result in
     * a call to the security manager's <code>checkPermission</code> method
     * with a
     * <code>SecurityPermission("insertProvider."+provider.getName())</code>
     * permission.
     * 
     * @param provider the provider to be added.
     *
     * @return the preference position in which the provider was 
     * added, or -1 if the provider was not added because it is
     * already installed.
     *
     * @throws  SecurityException
     *          if a security manager exists and its <code>{@link
     *          java.lang.SecurityManager#checkSecurityAccess}</code> method
     *          denies access to add a new provider
     * 
     * @see #getProvider
     * @see #removeProvider
     * @see java.security.SecurityPermission
     */
    public static int addProvider(Provider provider) {
	/*
 	 * We can't assign a position here because the statically
	 * registered providers may not have been installed yet. 
	 * insertProviderAt() will fix that value after it has 
	 * loaded the static providers.
 	 */
	return insertProviderAt(provider, 0);
    }

    /**
     * Removes the provider with the specified name.
     *
     * <p>When the specified provider is removed, all providers located
     * at a position greater than where the specified provider was are shifted
     * down one position (towards the head of the list of installed
     * providers).
     *
     * <p>This method returns silently if the provider is not installed.
     * 
     * <p>First, if there is a security manager, its
     * <code>checkSecurityAccess</code> 
     * method is called with the string <code>"removeProvider."+name</code> 
     * to see if it's ok to remove the provider. 
     * If the default implementation of <code>checkSecurityAccess</code> 
     * is used (i.e., that method is not overriden), then this will result in
     * a call to the security manager's <code>checkPermission</code> method
     * with a <code>SecurityPermission("removeProvider."+name)</code>
     * permission.
     *
     * @param name the name of the provider to remove.
     *
     * @throws  SecurityException
     *          if a security manager exists and its <code>{@link
     *          java.lang.SecurityManager#checkSecurityAccess}</code> method
     *          denies
     *          access to remove the provider
     *
     * @see #getProvider
     * @see #addProvider
     */
    public static synchronized void removeProvider(String name) {
	reloadProviders();
	check("removeProvider."+name);
	Provider provider = getProvider(name);
	if (provider != null) {
	    for (Iterator i=providers.iterator(); i.hasNext(); )
		if (i.next()==provider)
		    i.remove();

	    // empty provider-property cache
	    providerPropertiesCache.clear();
	    engineCache.clear();
	    searchResultsCache.clear();
	}
    }
    
    /**
     * Returns an array containing all the installed providers. The order of
     * the providers in the array is their preference order.
     * 
     * @return an array of all the installed providers.
     */
    public static synchronized Provider[] getProviders() {