File	Doc	Category	Size	Date	Package
ELParser.java	API Doc	Apache Tomcat 6.0.14	10750	Fri Jul 20 04:20:32 BST 2007	org.apache.jasper.compiler

ELParser

• java.lang.Object

Fields Summary
private Token	curToken
private ELNode.Nodes	expr
private ELNode.Nodes	ELexpr
private int	index
private String	expression
private char	type
private boolean	escapeBS
private static final String[]	reservedWords

Constructors Summary
public ELParser(String expression) index = 0; this.expression = expression; expr = new ELNode.Nodes();

Methods Summary
private int	getIndex() return index;
public char	getType() return type;
private boolean	hasNext() skipSpaces(); return hasNextChar();
private boolean	hasNextChar() return index < expression.length();
private boolean	isELReserved(java.lang.String id) Test if an id is a reserved word in EL int i = 0; int j = reservedWords.length; while (i < j) { int k = (i + j) / 2; int result = reservedWords[k].compareTo(id); if (result == 0) { return true; } if (result < 0) { i = k + 1; } else { j = k; } } return false;
private char	nextChar() if (index >= expression.length()) { return (char) -1; } return expression.charAt(index++);
private org.apache.jasper.compiler.ELParser$Token	nextToken() skipSpaces(); if (hasNextChar()) { char ch = nextChar(); if (Character.isJavaIdentifierStart(ch)) { StringBuffer buf = new StringBuffer(); buf.append(ch); while ((ch = peekChar()) != -1 && Character.isJavaIdentifierPart(ch)) { buf.append(ch); nextChar(); } return new Id(buf.toString()); } if (ch == '\'" || ch == '"") { return parseQuotedChars(ch); } else { // For now... return new Char(ch); } } return null;
public static ELNode.Nodes	parse(java.lang.String expression) Parse an EL expression param expression The input expression string of the form Char* ('${' Char* '}')* Char* return Parsed EL expression in ELNode.Nodes ELParser parser = new ELParser(expression); while (parser.hasNextChar()) { String text = parser.skipUntilEL(); if (text.length() > 0) { parser.expr.add(new ELNode.Text(text)); } ELNode.Nodes elexpr = parser.parseEL(); if (!elexpr.isEmpty()) { parser.expr.add(new ELNode.Root(elexpr, parser.type)); } } return parser.expr;
private ELNode.Nodes	parseEL() Parse an EL expression string '${...}' return An ELNode.Nodes representing the EL expression TODO: Currently only parsed into functions and text strings. This should be rewritten for a full parser. StringBuffer buf = new StringBuffer(); ELexpr = new ELNode.Nodes(); while (hasNext()) { curToken = nextToken(); if (curToken instanceof Char) { if (curToken.toChar() == '}") { break; } buf.append(curToken.toChar()); } else { // Output whatever is in buffer if (buf.length() > 0) { ELexpr.add(new ELNode.ELText(buf.toString())); } if (!parseFunction()) { ELexpr.add(new ELNode.ELText(curToken.toString())); } } } if (buf.length() > 0) { ELexpr.add(new ELNode.ELText(buf.toString())); } return ELexpr;
private boolean	parseFunction() Parse for a function FunctionInvokation ::= (identifier ':')? identifier '(' (Expression (,Expression)*)? ')' Note: currently we don't parse arguments if (!(curToken instanceof Id) || isELReserved(curToken.toString())) { return false; } String s1 = null; // Function prefix String s2 = curToken.toString(); // Function name int mark = getIndex(); if (hasNext()) { Token t = nextToken(); if (t.toChar() == ':") { if (hasNext()) { Token t2 = nextToken(); if (t2 instanceof Id) { s1 = s2; s2 = t2.toString(); if (hasNext()) { t = nextToken(); } } } } if (t.toChar() == '(") { ELexpr.add(new ELNode.Function(s1, s2)); return true; } } setIndex(mark); return false;
private org.apache.jasper.compiler.ELParser$Token	parseQuotedChars(char quote) StringBuffer buf = new StringBuffer(); buf.append(quote); while (hasNextChar()) { char ch = nextChar(); if (ch == '\\") { ch = nextChar(); if (ch == '\\" || ch == quote) { buf.append(ch); } // else error! } else if (ch == quote) { buf.append(ch); break; } else { buf.append(ch); } } return new QuotedString(buf.toString());
private char	peekChar() if (index >= expression.length()) { return (char) -1; } return expression.charAt(index);
private void	setIndex(int i) index = i;
private void	skipSpaces() while (hasNextChar()) { if (expression.charAt(index) > ' ") break; index++; }
private java.lang.String	skipUntilEL() Skip until an EL expression ('${' || '#{') is reached, allowing escape sequences '\\' and '\$' and '\#'. return The text string up to the EL expression char prev = 0; StringBuffer buf = new StringBuffer(); while (hasNextChar()) { char ch = nextChar(); if (prev == '\\") { prev = 0; if (ch == '\\") { buf.append('\\"); if (!escapeBS) prev = '\\"; } else if (ch == '$" || ch == '#") { buf.append(ch); } // else error! } else if (prev == '$" || prev == '#") { if (ch == '{") { this.type = prev; prev = 0; break; } buf.append(prev); prev = 0; } if (ch == '\\" || ch == '$" || ch == '#") { prev = ch; } else { buf.append(ch); } } if (prev != 0) { buf.append(prev); } return buf.toString();