urlconnection.java

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	/*************************************************************************/

	/**
	  * Returns a boolean flag indicating whether or not output will be done
	  * on this connection.  The default value is false, so this method can
	  * be used to override the default
	  *
	  * @param output ture if output is to be done, false otherwise
	  */
	public void setDoOutput(boolean output) {
		doOutput = output;
	}

	/*************************************************************************/

	/**
	  * Returns a boolean flag indicating whether or not caching will be used
	  * (if possible) to store data downloaded via the connection.
	  *
	  * @return true if caching should be used if possible, false otherwise
	  */
	public boolean getUseCaches() {
		return (useCaches);
	}

	/*************************************************************************/

	/**
	  * Sets a boolean flag indicating whether or not caching will be used
	  * (if possible) to store data downloaded via the connection.
	  *
	  * @param use_cache true if caching should be used if possible, false otherwise
	  */
	public void setUseCaches(boolean use_caches) {
		useCaches = use_caches;
	}

	/*************************************************************************/

	/**
	  * Returns the ifModified since instance variable.  If this value is non
	  * zero and the underlying protocol supports it, the actual document will
	  * not be fetched unless it has been modified since this time.  The value
	  * returned will be 0 if this feature is disabled or the time expressed
	  * as the number of seconds since midnight 1/1/1970 GMT otherwise
	  *
	  * @return The ifModifiedSince value
	  */
	public long getIfModifiedSince() {
		return (ifModifiedSince);
	}

	/*************************************************************************/

	/**
	  * Sets the ifModified since instance variable.  If this value is non
	  * zero and the underlying protocol supports it, the actual document will
	  * not be fetched unless it has been modified since this time.  The value
	  * passed should  be 0 if this feature is to be disabled or the time expressed
	  * as the number of seconds since midnight 1/1/1970 GMT otherwise.
	  *
	  * @param modified_since The new ifModifiedSince value
	  */
	public void setIfModifiedSince(long modified_since) {
		ifModifiedSince = modified_since;
	}

	/*************************************************************************/

	/**
	  * Returns the value of the named request property.
	  *
	  * @param key The name of the property
	  *
	  * @return The value of the property
	  */
	public String getRequestProperty(String key) {
		return ((String) req_props.get(key.toLowerCase()));
	}

	/*************************************************************************/

	/**
	  * Sets the value of the named request property
	  *
	  * @param key The name of the property
	  * @param value The value of the property
	  */
	public void setRequestProperty(String key, String value) {
		req_props.put(key.toLowerCase(), value);
	}

	/**
	 * Returns an unmodifiable Map containing the request properties.
	 *
	 * @since 1.4
	 */
	public Map getRequestProperties() {
		return Collections.unmodifiableMap(req_props);
	}

	/*************************************************************************/

	/**
	  * Returns the URL object associated with this connection
	  *
	  * @return The URL for this connection.
	  */
	public URL getURL() {
		return (url);
	}

	/*************************************************************************/

	/**
	  * Establishes the actual connection to the URL associated with this
	  * connection object
	  */
	public abstract void connect() throws IOException;

	/*************************************************************************/

	/**
	  * Returns an InputStream for this connection.  As this default
	  * implementation returns null, subclasses should override this method
	  *
	  * @return An InputStream for this connection
	  *
	  * @exception IOException If an error occurs
	  */
	public InputStream getInputStream() throws IOException {
		return (null);
	}

	/*************************************************************************/

	/**
	  * Returns an OutputStream for this connection.  As this default
	  * implementation returns null, subclasses should override this method
	  *
	  * @return An OutputStream for this connection
	  *
	  * @exception IOException If an error occurs
	  */
	public OutputStream getOutputStream() throws IOException {
		return (null);
	}

	/*************************************************************************/

	/**
	  * Returns the value of the content-encoding field or null if it is not
	  * known or not present.
	  * 
	  * @return The content-encoding field
	  */
	public String getContentEncoding() {
		return (getHeaderField("content-encoding"));
	}

	/*************************************************************************/

	/**
	  * Returns the value of the content-length header field or -1 if the value
	  * is not known or not present.
	  *
	  * @return The content-length field
	  */
	public int getContentLength() {
		return (getHeaderFieldInt("content-length", -1));
	}

	/*************************************************************************/

	/**
	  * Returns the the content-type of the data pointed to by the URL.  This
	  * method first tries looking for a content-type header.  If that is not
	  * present, it attempts to use the file name to determine the content's
	  * MIME type.  If that is unsuccessful, the method returns null.  The caller
	  * may then still attempt to determine the MIME type by a call to
	  * guessContentTypeFromStream()
	  *
	  * @return The content MIME type
	  */
	public String getContentType() {
		String type = getHeaderField("content-type");
		if (type == null)
			type = guessContentTypeFromName(getURL().getFile());

		return (type);
	}

	/*************************************************************************/

	/**
	  * Returns the date of the document pointed to by the URL as reported in
	  * the date field of the header or 0 if the value is not present or not
	  * known. If populated, the return value is number of seconds since
	  * midnight on 1/1/1970 GMT.
	  *
	  * @return The document date
	  */
	public long getDate() {
		return (getHeaderFieldDate("date", 0));
	}

	/*************************************************************************/

	/**
	  * Returns the value of the expires header or 0 if not known or present.
	  * If populated, the return value is number of seconds since midnight
	  * on 1/1/1970 GMT.
	  *
	  * @return The expiration time.
	  */
	public long getExpiration() {
		return (getHeaderFieldDate("expires", 0));
	}

	/*************************************************************************/

	/**
	  * Returns the value of the last-modified header field or 0 if not known known
	  * or not present.  If populated, the return value is the number of seconds
	  * since midnight on 1/1/1970.
	  *
	  * @return The last modified time
	  */
	public long getLastModified() {
		return (getHeaderFieldDate("last-modified", 0));
	}

	/*************************************************************************/

	/**
	  * Returns a String representing the header key at the specified index.
	  * This allows the caller to walk the list of header fields.  The analogous
	  * getHeaderField(int) method allows access to the corresponding value for
	  * this tag.
	  *
	  * @param index The index into the header field list to retrieve the key for. 
	  *
	  * @return The header field key or null if index is past the end of the headers
	  */
	public String getHeaderFieldKey(int index) {
		return (null);
	}

	/*************************************************************************/

	/**
	  * Return a String representing the header value at the specified index.
	  * This allows the caller to walk the list of header fields.  The analogous
	  * getHeaderFieldKey(int) method allows access to the corresponding key
	  * for this header field
	  *
	  * @param index The index into the header field list to retrieve the value for
	  *
	  * @return The header value or null if index is past the end of the headers
	  */
	public String getHeaderField(int index) {
		return (null);
	}

	/*************************************************************************/

	/**
	  * Returns a String representing the value of the header field having
	  * the named key.  Returns null if the header field does not exist.
	  *
	  * @param The key of the header field
	  *
	  * @return The value of the header field as a String
	  */
	public String getHeaderField(String name) {
		for (int i = 0;; i++) {
			String key = getHeaderFieldKey(i);
			if (key == null)
				return (null);

			if (key.toLowerCase().equals(name.toLowerCase()))
				return (getHeaderField(i));
		}
	}

	/*************************************************************************/

	/**
	  * Returns the value of the named header field as a date.  This date will
	  * be the number of seconds since midnight 1/1/1970 GMT or the default
	  * value if the field is not present or cannot be converted to a date.
	  *
	  * @param key The header field key to lookup
	  * @param def The default value if the header field is not found or can't be converted
	  */
	public long getHeaderFieldDate(String key, long def) {
		String value = getHeaderField(key);
		if (value == null)
			return (def);

		// This needs to change since Date(String) is deprecated, but DateFormat
		// doesn't seem to be working for some reason
		//DateFormat df = DateFormat.getDateInstance(DateFormat.FULL, Locale.US);
		//df.setLenient(true);

		//Date d = df.parse(value, new ParsePosition(0));
		Date d = new Date(value);

		if (d == null)
			return (def);

		return (d.getTime() / 1000);
	}

	/*************************************************************************/

	/**
	  * Returns the value of the named header field as an int.  If the field
	  * is not present or cannot be parsed as an integer, the default value
	  * will be returned.
	  *
	  * @param key The header field key to lookup
	  * @param def The defaule value if the header field is not found or can't be parsed
	  */
	public int getHeaderFieldInt(String key, int def) {
		String value = getHeaderField(key);
		if (value == null)
			return (def);

		int retval = def;
		try {
			retval = Integer.parseInt(value);
		} catch (NumberFormatException e) {
			return (def);
		}

		return (retval);
	}

	/*************************************************************************/

	/**
	  * This method returns a <code>Permission</code> object representing the
	  * permissions required to access this URL.  This method returns
	  * <code>java.security.AllPermission</code> by default.  Subclasses should
	  * override it to return a more specific permission.  For example, an
	  * HTTP URL should return an instance of <code>SocketPermission</code>
	  * for the appropriate host and port.
	  * <p>
	  * Note that because of items such as HTTP redirects, the permission
	  * object returned might be different before and after connecting.
	  *
	  * @return A Permission object
	  *
	  * @exception IOException If an error occurs
	  */
	public Permission getPermission() throws IOException {
		return (new java.security.AllPermission());
	}

	/*************************************************************************/

	/**
	  * This method returns the content of the document pointed to by the URL
	  * as an Object.  The type of object depends on the MIME type of the
	  * object and particular content hander loaded.  Most text type content
	  * handlers will return a subclass of InputStream.  Images usually return
	  * a class that implements ImageProducer.  There is not guarantee what
	  * type of object will be returned, however.
	  * <p>
	  * This class first determines the MIME type of the content, then creates
	  * a ContentHandler object to process the input.  If the ContentHandlerFactory
	  * is set, then that object is called to load a content handler, otherwise
	  * a class called gnu.java.net.content.<content_type> is tried.
	  * The default class will also be used if the content handler factory returns
	  * a null content handler.
	  *
	  * @exception IOException If an error occurs.
	  */
	public Object getContent() throws IOException {
		//  connect();
		String type = getContentType();

		// First try the factory
		ContentHandler ch = null;
		if (factory != null)
			ch = factory.createContentHandler(type);

		if (ch != null)
			return (ch.getContent(this));

		// Then try our default class
		try {
			Class cls = Class.forName("gnu.java.net.content." + type.replace('/', '.'));

			Object obj = cls.newInstance();
			if (!(obj instanceof ContentHandler))
				throw new UnknownServiceException(type);

			ch = (ContentHandler) obj;
			return (ch.getContent(this));
		} catch (ClassNotFoundException e) {
			// Do nothing
		} catch (InstantiationException e) {
			// Do nothing
		} catch (IllegalAccessException e) {
			// Do nothing
		}

		throw new UnknownServiceException(type);
	}

	/*************************************************************************/

	/**
	  * The methods prints the value of this object as a String by calling the
	  * toString() method of its associated URL.  Overrides Object.toString()
	  * 
	  * @return A String representation of this object
	  */
	public String toString() {
		return (url.toString());
	}

} // class URLConnection