parser.java

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		//3: nested content
		final int nestedFrom = ++j, nestedTo;
		for (int depth = 0;; ++j) {
			if (j >= to)
				throw new ServletException(MWeb.DSP_ACTION_NOT_TERMINATED,
					new Object[] {actnm, new Integer(action.getLineNumber())});

			cc = ctx.content.charAt(j);
			if (j + 1 < to) {
				if (cc == '<') {
					final int oldLines = ctx.nLines;
					k = j + 1;
					ended = ctx.content.charAt(k) == '/';
					k = skipWhitespaces(ctx, ended ? k + 1: k, to);
					int l = nextSeparator(ctx, k, to);
					if (l >= to || ctx.content.charAt(l) != ':'
					|| !prefix.equals(ctx.content.substring(k, l))) {
						ctx.nLines = oldLines;
						continue; //bypass
					}

					k = skipWhitespaces(ctx, l + 1, to);
					l = nextSeparator(ctx, k, to);
					if (l >= to || !actnm.equals(ctx.content.substring(k, l))) {
						ctx.nLines = oldLines;
						continue; //bypass
					}
					l = skipWhitespaces(ctx, l, to);
					if (l >= to || (ended && ctx.content.charAt(l) != '>')) {
						ctx.nLines = oldLines;
						continue; //bypass
					}

					if (ended) {
						if (--depth < 0) {
							nestedTo = j;
							j = l;
							break; //done
						}
					} else {
						++depth;
					}
					j = l;
					continue;
				} else if (cc == '$' && ctx.content.charAt(j + 1) == '{') {
					j = endOfEL(ctx, j, to);
					continue;
				}
			}
			if (cc == '\n') ++ctx.nLines;
		}

		parse0(ctx, action, nestedFrom, nestedTo); //recursive
		return j;
	}
	private static boolean startsWith(String content, int from, int to, String s) {
		for (int j = 0, len = s.length(); ; ++from, ++j) {
			if (j >= len) return true;
			if (from >= to || content.charAt(from) != s.charAt(j)) return false;
		}
	}
	private static int skipWhitespaces(Context ctx, int from, int to) {
		for (; from < to; ++from) {
			final char cc = ctx.content.charAt(from);
			if (cc == '\n') ++ctx.nLines;
			else if (!Character.isWhitespace(cc))
				break;
		}
		return from;
	}
	private static int nextSeparator(Context ctx, int from, int to) {
		for (; from < to; ++from) {
			final char cc = ctx.content.charAt(from);
			if ((cc < '0' || cc > '9') && (cc < 'a' || cc > 'z')
			&& (cc < 'A' || cc > 'Z') && cc != '_')
				break;
		}
		return from;
	}
	/** Parses the attributes.
	 */
	private static int parseAttrs(Context ctx, Map attrs, String actnm,
	int from, int to)
	throws javax.servlet.ServletException {
		for (int j, k = from;;) {
			j = skipWhitespaces(ctx, k, to);
			k = nextSeparator(ctx, j, to);
			if (k >= to)
				throw new ServletException(MWeb.DSP_ACTION_NOT_TERMINATED,
					new Object[] {actnm, new Integer(ctx.nLines)});
			if (j == k) return j;

			final String attrnm = ctx.content.substring(j, k);
			k = skipWhitespaces(ctx, k, to);
			j = skipWhitespaces(ctx, k + 1, to);
			if (j >= to || ctx.content.charAt(k) != '=')
				throw new ServletException(MWeb.DSP_ATTRIBUTE_VALUE_REQUIRED,
					new Object[] {actnm, attrnm, new Integer(ctx.nLines)});

			final char quot = ctx.content.charAt(j);
			if (quot != '"' && quot != '\'')
				throw new ServletException(MWeb.DSP_ATTRIBUTE_VALUE_QUOTE_REQUIRED,
					new Object[] {actnm, attrnm, new Integer(ctx.nLines)});

			final StringBuffer sbval = new StringBuffer();
			for (k = ++j;; ++k) {
				if (k >= to)
					throw new ServletException(MWeb.DSP_ATTRIBUTE_VALUE_QUOTE_REQUIRED,
						new Object[] {actnm, attrnm, new Integer(ctx.nLines)});
				final char cc = ctx.content.charAt(k);
				if (cc == '\n')
					throw new ServletException(MWeb.DSP_ATTRIBUTE_VALUE_QUOTE_REQUIRED,
						new Object[] {actnm, attrnm, new Integer(ctx.nLines)});

				if (cc == quot) {
					++k;
					break; //found
				}

				sbval.append(cc);
				if (cc == '\\' && ++k < to)
					sbval.setCharAt(sbval.length() - 1, ctx.content.charAt(k));
			}

			attrs.put(attrnm, sbval.toString());
		}
	}
	/** Applies attributes.
	 */
	private static final
	void applyAttrs(String actnm, ActionNode action, Map attrs)
	throws javax.servlet.ServletException {
		for (Iterator it = attrs.entrySet().iterator(); it.hasNext();) {
			final Map.Entry me = (Map.Entry)it.next();
			final String attrnm = (String)me.getKey();
			final String attrval = (String)me.getValue();
			try {
				action.addAttribute(attrnm, attrval);
			} catch (NoSuchMethodException ex) {
				throw new ServletException(MWeb.DSP_ATTRIBUTE_NOT_FOUND,
					new Object[] {actnm, attrnm, new Integer(action.getLineNumber())});
			} catch (ClassCastException ex) {
				throw new ServletException(MWeb.DSP_ATTRIBUTE_INVALID_VALUE,
					new Object[] {actnm, attrnm, attrval, new Integer(action.getLineNumber())}, ex);
			}
		}
	}

	/** Parses an EL expression starting at from.
	 * @return the position of }.
	 */
	private static int parseEL(Context ctx, Node parent, int from, int to)
	throws javax.servlet.ServletException {
		int j = endOfEL(ctx, from, to); //point to }
		parent.addChild(new ELNode(ctx.content.substring(from, j + 1)));
		return j;
	}
	/** Returns the position of '}'. */
	private static int endOfEL(Context ctx, int from, int to)
	throws javax.servlet.ServletException {
		for (int j = from + 2;; ++j) {
			if (j >= to)
				throw new ServletException(MWeb.EL_NOT_TERMINATED, new Integer(ctx.nLines));

			final char cc = ctx.content.charAt(j);
			if (cc == '}') {
				return j;
			} else if (cc == '\'' || cc == '"') {
				while (++j < to) {
					final char c2 = ctx.content.charAt(j);
					if (c2 == cc) break;
					if (cc == '\n')
						throw new ServletException("Illegal EL expression: non-terminaled "+cc+" at line "+ctx.nLines+" character "+j);
					if (c2 == '\\' && ++j < to && ctx.content.charAt(j) == '\n')
						++ctx.nLines;
				}
			} else if (cc == '\n') {
				++ctx.nLines;
			}
		}
	}

	/** Adds a text node. */
	private static void addText(Node parent, StringBuffer sb) {
		if (sb.length() > 0) {
			parent.addChild(new TextNode(sb.toString()));
			sb.setLength(0);
		}
	}

	/** Context used during parsing. */
	private static class Context {
		private final String content;
		private final SimpleMapper mapper;
		/** (String prefix, Map(String name, Class class)). */
		private final Map _actions = new HashMap();
		private final Locator locator;
		private int nLines;
		/** Whether the page action is defined. */
		private boolean pageDefined;
		private Context(String content, FunctionMapper fm, Locator loc) {
			this.content = content;
			this.mapper = new SimpleMapper(fm);
			this.locator = loc;
			this.nLines = 1;
		}
		private boolean hasPrefix(String prefix) {
			return _actions.containsKey(prefix);
		}
		private Class getActionClass(String prefix, String actnm) {
			final Map acts = (Map)_actions.get(prefix);
			return acts != null ? (Class)acts.get(actnm): null;
		}
		private void loadTaglib(String prefix, String uri)
		throws javax.servlet.ServletException, IOException {
			if (D.ON && log.debugable()) log.debug("Loading "+prefix+" at "+uri);
			if (this.locator == null)
				throw new ServletException("Unable to load "+uri+" because locator is not specified");

			final URL url = this.locator.getResource(uri);
			if (url == null)
				throw new FileNotFoundException(uri);

			try {
				loadTaglib0(prefix, url);
			} catch (IOException ex) {
				throw ex;
			} catch (Exception ex) {
				throw ServletException.Aide.wrap(ex);
			}

		}
		private void loadTaglib0(String prefix, URL url)
		throws Exception {
			final Element root = new SAXBuilder(true, false, true)
				.build(url).getRootElement();
			mapper.load(prefix, root);

			final Map acts = new HashMap();
			for (Iterator it = root.getElements("tag").iterator();
			it.hasNext();) {
				final Element e = (Element)it.next();
				final String name = IDOMs.getRequiredElementValue(e, "name");
				final String clsName = IDOMs.getRequiredElementValue(e, "tag-class");
				final Class cls = Classes.forNameByThread(clsName);
				if (!Action.class.isAssignableFrom(cls))
					throw new ServletException(cls+" doesn't implement "+Action.class);
				acts.put(name, cls);
//				if (D.ON && log.finerable()) log.finer("Action "+prefix+":"+name+" are added");
			}
			if (!acts.isEmpty())
				_actions.put(prefix, acts);
		}
	}
}