urlconnection.java

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     * Sets the default value of the 
     * <code>allowUserInteraction</code> field for all future 
     * <code>URLConnection</code> objects to the specified value. 
     *
     * @param   defaultallowuserinteraction   the new value.
     * @see     #getDefaultAllowUserInteraction()
     */
    public static void setDefaultAllowUserInteraction(boolean defaultallowuserinteraction) {
	defaultAllowUserInteraction = defaultallowuserinteraction;
    }

    /**
     * Returns the default value of the <code>allowUserInteraction</code>
     * field.
     * <p>
     * Ths default is "sticky", being a part of the static state of all
     * URLConnections.  This flag applies to the next, and all following
     * URLConnections that are created.
     *
     * @return  the default value of the <code>allowUserInteraction</code>
     *          field.
     * @see     #setDefaultAllowUserInteraction(boolean)
     */
    public static boolean getDefaultAllowUserInteraction() {
	return defaultAllowUserInteraction;
    }

    /**
     * Sets the value of the <code>useCaches</code> field of this 
     * <code>URLConnection</code> to the specified value. 
     * <p>
     * Some protocols do caching of documents.  Occasionally, it is important
     * to be able to "tunnel through" and ignore the caches (e.g., the
     * "reload" button in a browser).  If the UseCaches flag on a connection
     * is true, the connection is allowed to use whatever caches it can.
     *  If false, caches are to be ignored.
     *  The default value comes from DefaultUseCaches, which defaults to
     * true.
     *
     * @param usecaches a <code>boolean</code> indicating whether 
     * or not to allow caching
     * @throws IllegalStateException if already connected
     * @see #getUseCaches()
     */
    public void setUseCaches(boolean usecaches) {
	if (connected)
	    throw new IllegalStateException("Already connected");
	useCaches = usecaches;
    }

    /**
     * Returns the value of this <code>URLConnection</code>'s
     * <code>useCaches</code> field.
     *
     * @return  the value of this <code>URLConnection</code>'s
     *          <code>useCaches</code> field.
     * @see #setUseCaches(boolean)
     */
    public boolean getUseCaches() {
	return useCaches;
    }

    /**
     * Sets the value of the <code>ifModifiedSince</code> field of 
     * this <code>URLConnection</code> to the specified value.
     *
     * @param   ifmodifiedsince   the new value.
     * @throws IllegalStateException if already connected
     * @see     #getIfModifiedSince()
     */
    public void setIfModifiedSince(long ifmodifiedsince) {
	if (connected)
	    throw new IllegalStateException("Already connected");
	ifModifiedSince = ifmodifiedsince;
    }

    /**
     * Returns the value of this object's <code>ifModifiedSince</code> field.
     *
     * @return  the value of this object's <code>ifModifiedSince</code> field.
     * @see #setIfModifiedSince(long)
     */
    public long getIfModifiedSince() {
	return ifModifiedSince;
    }

   /**
     * Returns the default value of a <code>URLConnection</code>'s
     * <code>useCaches</code> flag.
     * <p>
     * Ths default is "sticky", being a part of the static state of all
     * URLConnections.  This flag applies to the next, and all following
     * URLConnections that are created.
     *
     * @return  the default value of a <code>URLConnection</code>'s
     *          <code>useCaches</code> flag.
     * @see     #setDefaultUseCaches(boolean)
     */
    public boolean getDefaultUseCaches() {
	return defaultUseCaches;
    }

   /**
     * Sets the default value of the <code>useCaches</code> field to the 
     * specified value. 
     *
     * @param   defaultusecaches   the new value.
     * @see     #getDefaultUseCaches()
     */
    public void setDefaultUseCaches(boolean defaultusecaches) {
	defaultUseCaches = defaultusecaches;
    }

    /**
     * Sets the general request property. If a property with the key already
     * exists, overwrite its value with the new value.
     *
     * <p> NOTE: HTTP requires all request properties which can
     * legally have multiple instances with the same key
     * to use a comma-seperated list syntax which enables multiple
     * properties to be appended into a single property.
     *
     * @param   key     the keyword by which the request is known
     *                  (e.g., "<code>accept</code>").
     * @param   value   the value associated with it.
     * @throws IllegalStateException if already connected
     * @throws NullPointerException if key is <CODE>null</CODE>
     * @see #getRequestProperty(java.lang.String)
     */
    public void setRequestProperty(String key, String value) {
	if (connected)
	    throw new IllegalStateException("Already connected");
	if (key == null) 
	    throw new NullPointerException ("key is null");
    }

    /**
     * Adds a general request property specified by a
     * key-value pair.  This method will not overwrite
     * existing values associated with the same key.
     *
     * @param   key     the keyword by which the request is known
     *                  (e.g., "<code>accept</code>").
     * @param   value  the value associated with it.
     * @throws IllegalStateException if already connected
     * @throws NullPointerException if key is null
     * @see #getRequestProperties(java.lang.String)
     * @since 1.4
     */
    public void addRequestProperty(String key, String value) {
	if (connected)
	    throw new IllegalStateException("Already connected");
	if (key == null) 
	    throw new NullPointerException ("key is null");
    }


    /**
     * Returns the value of the named general request property for this
     * connection.
     *
     * @param key the keyword by which the request is known (e.g., "accept").
     * @return  the value of the named general request property for this
     *           connection. If key is null, then null is returned.
     * @throws IllegalStateException if already connected
     * @see #setRequestProperty(java.lang.String, java.lang.String)
     */
    public String getRequestProperty(String key) {
	if (connected)
	    throw new IllegalStateException("Already connected");
	return null;
    }

    /**
     * Returns an unmodifiable Map of general request
     * properties for this connection. The Map keys
     * are Strings that represent the request-header
     * field names. Each Map value is a unmodifiable List 
     * of Strings that represents the corresponding 
     * field values.
     *
     * @return  a Map of the general request properties for this connection.
     * @throws IllegalStateException if already connected
     * @since 1.4
     */
    public Map getRequestProperties() {
        if (connected)
            throw new IllegalStateException("Already connected");
	return Collections.EMPTY_MAP;
    }

    /**
     * Sets the default value of a general request property. When a 
     * <code>URLConnection</code> is created, it is initialized with 
     * these properties. 
     *
     * param   key     the keyword by which the request is known
     *                  (e.g., "<code>accept</code>").
     * param   value   the value associated with the key.
     *
     * see java.net.URLConnection#setRequestProperty(java.lang.String,java.lang.String) 
     *
     * deprecated The instance specific setRequestProperty method
     * should be used after an appropriate instance of URLConnection
     * is obtained.
     *
     * see #getDefaultRequestProperty(java.lang.String)
     *
    public static void setDefaultRequestProperty(String key, String value) {
    }
     */

    /**
     * Returns the value of the default request property. Default request 
     * properties are set for every connection. 
     *
     * param key the keyword by which the request is known (e.g., "accept").
     * return  the value of the default request property 
     * for the specified key.
     *
     * see java.net.URLConnection#getRequestProperty(java.lang.String)
     *
     * deprecated The instance specific getRequestProperty method
     * should be used after an appropriate instance of URLConnection
     * is obtained.
     *
     * see #setDefaultRequestProperty(java.lang.String, java.lang.String)
     *
    public static String getDefaultRequestProperty(String key) {
	return null;
    }
     */

    /**
     * The ContentHandler factory.
     */
    static ContentHandlerFactory factory;

    /**
     * Sets the <code>ContentHandlerFactory</code> of an 
     * application. It can be called at most once by an application. 
     * <p>
     * The <code>ContentHandlerFactory</code> instance is used to 
     * construct a content handler from a content type 
     * <p>
     * If there is a security manager, this method first calls
     * the security manager's <code>checkSetFactory</code> method 
     * to ensure the operation is allowed. 
     * This could result in a SecurityException.
     *
     * @param      fac   the desired factory.
     * @exception  Error  if the factory has already been defined.
     * @exception  SecurityException  if a security manager exists and its  
     *             <code>checkSetFactory</code> method doesn't allow the operation.
     * @see        java.net.ContentHandlerFactory
     * @see        java.net.URLConnection#getContent()
     * @see        SecurityManager#checkSetFactory
     */
    public static synchronized void setContentHandlerFactory(ContentHandlerFactory fac) {
	if (factory != null) {
	    throw new Error("factory already defined");
	}
	SecurityManager security = System.getSecurityManager();
	if (security != null) {
	    security.checkSetFactory();
	}
	factory = fac;
    }

    private static Hashtable handlers = new Hashtable();
    private static final ContentHandler UnknownContentHandlerP = new UnknownContentHandler();

    /**
     * Gets the Content Handler appropriate for this connection.
     * @param connection the connection to use.
     */
    synchronized ContentHandler getContentHandler()
    throws UnknownServiceException
    {
	String contentType = stripOffParameters(getContentType());
	ContentHandler handler = null;
	if (contentType == null)
	    throw new UnknownServiceException("no content-type");
	try {
	    handler = (ContentHandler) handlers.get(contentType);
	    if (handler != null)
		return handler;
	} catch(Exception e) {
	}

	if (factory != null)
	    handler = factory.createContentHandler(contentType);
	if (handler == null) {
	    try {
		handler = lookupContentHandlerClassFor(contentType);
	    } catch(Exception e) {
		e.printStackTrace();
		handler = UnknownContentHandlerP;
	    }
	    handlers.put(contentType, handler);
	}
	return handler;
    }

    /*
     * Media types are in the format: type/subtype*(; parameter).
     * For looking up the content handler, we should ignore those
     * parameters.
     */
    private String stripOffParameters(String contentType)
    {
	if (contentType == null)
	    return null;
	int index = contentType.indexOf(';');

	if (index > 0)
	    return contentType.substring(0, index);
	else
	    return contentType;
    }

    private static final String contentClassPrefix = "sun.net.www.content";
    private static final String contentPathProp = "java.content.handler.pkgs";

    /**
     * Looks for a content handler in a user-defineable set of places.
     * By default it looks in sun.net.www.content, but users can define a 
     * vertical-bar delimited set of class prefixes to search through in 
     * addition by defining the java.content.handler.pkgs property.
     * The class name must be of the form:
     * <pre>
     *     {package-prefix}.{major}.{minor}
     * e.g.
     *     YoyoDyne.experimental.text.plain
     * </pre>
     */
    private ContentHandler lookupContentHandlerClassFor(String contentType)
	throws InstantiationException, IllegalAccessException, ClassNotFoundException {
	String contentHandlerClassName = typeToPackageName(contentType);

	String contentHandlerPkgPrefixes =getContentHandlerPkgPrefixes();

	StringTokenizer packagePrefixIter =
	    new StringTokenizer(contentHandlerPkgPrefixes, "|");
	
	while (packagePrefixIter.hasMoreTokens()) {
	    String packagePrefix = packagePrefixIter.nextToken().trim();

	    try {
		String clsName = packagePrefix + "." + contentHandlerClassName;
		Class cls = null;
		try {
		    cls = Class.forName(clsName);
		} catch (ClassNotFoundException e) {
		    ClassLoader cl = ClassLoader.getSystemClassLoader();
		    if (cl != null) {
			cls = cl.loadClass(clsName);
		    }
		}
		if (cls != null) {
		    ContentHandler handler = 
			(ContentHandler)cls.newInstance();
		    return handler;
		}
	    } catch(Exception e) {
	    }
	}
	
	return UnknownContentHandlerP;
    }

    /**
     * Utility function to map a MIME content type into an equivalent
     * pair of class name components.  For example: "text/html" would
     * be returned as "text.html"
     */
    private String typeToPackageName(String contentType) {
	// make sure we canonicalize the class name: all lower case
	contentType = contentType.toLowerCase();
	int len = contentType.length();
	char nm[] = new char[len];
	contentType.getChars(0, len, nm, 0);
	for (int i = 0; i < len; i++) {
	    char c = nm[i];
	    if (c == '/') {
		nm[i] = '.';
	    } else if (!('A' <= c && c <= 'Z' ||
		       'a' <= c && c <= 'z' ||
		       '0' <= c && c <= '9')) {
		nm[i] = '_';
	    }
	}
	return new String(nm);
    }


    /**
     * Returns a vertical bar separated list of package prefixes for potential
     * content handlers.  Tries to get the java.content.handler.pkgs property
     * to use as a set of package prefixes to search.  Whether or not
     * that property has been defined, the sun.net.www.content is always