/* * The Apache Software License, Version 1.1 * * Copyright (c) 1999 The Apache Software Foundation. All rights * reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in * the documentation and/or other materials provided with the * distribution. * * 3. The end-user documentation included with the redistribution, if * any, must include the following acknowlegement: * "This product includes software developed by the * Apache Software Foundation (http://www.apache.org/)." * Alternately, this acknowlegement may appear in the software itself, * if and wherever such third-party acknowlegements normally appear. * * 4. 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For more * information on the Apache Software Foundation, please see * <http://www.apache.org/>. * */ package org.jbpm.jpdl.el.impl; /** * * <p>An expression representing a String literal value. * * @author Nathan Abramson - Art Technology Group * @version $Change: 181177 $$DateTime: 2001/06/26 08:45:09 $$Author$ **/ public class StringLiteral extends Literal { //------------------------------------- /** * * Constructor **/ StringLiteral (Object pValue) { super (pValue); } //------------------------------------- /** * * Returns a StringLiteral parsed from the given token (enclosed by * single or double quotes) **/ public static StringLiteral fromToken (String pToken) { return new StringLiteral (getValueFromToken (pToken)); } //------------------------------------- /** * * Returns a StringLiteral with the given string value **/ public static StringLiteral fromLiteralValue (String pValue) { return new StringLiteral (pValue); } //------------------------------------- /** * * Parses the given token into the literal value **/ public static String getValueFromToken (String pToken) { StringBuffer buf = new StringBuffer (); int len = pToken.length () - 1; boolean escaping = false; for (int i = 1; i < len; i++) { char ch = pToken.charAt (i); if (escaping) { buf.append (ch); escaping = false; } else if (ch == '\\') { escaping = true; } else { buf.append (ch); } } return buf.toString (); } //------------------------------------- /** * * Converts the specified value to a String token, using " as the * enclosing quotes and escaping any characters that need escaping. **/ public static String toStringToken (String pValue) { // See if any escaping is needed if (pValue.indexOf ('\"') < 0 && pValue.indexOf ('\\') < 0) { return "\"" + pValue + "\""; } // Escaping is needed else { StringBuffer buf = new StringBuffer (); buf.append ('\"'); int len = pValue.length (); for (int i = 0; i < len; i++) { char ch = pValue.charAt (i); if (ch == '\\') { buf.append ('\\'); buf.append ('\\'); } else if (ch == '\"') { buf.append ('\\'); buf.append ('\"'); } else { buf.append (ch); } } buf.append ('\"'); return buf.toString (); } } //------------------------------------- /** * * Converts the specified value to an identifier token, escaping it * as a string literal if necessary. **/ public static String toIdentifierToken (String pValue) { // See if it's a valid java identifier if (isJavaIdentifier (pValue)) { return pValue; } // Return as a String literal else { return toStringToken (pValue); } } //------------------------------------- /** * * Returns true if the specified value is a legal java identifier **/ static boolean isJavaIdentifier (String pValue) { int len = pValue.length (); if (len == 0) { return false; } else { if (!Character.isJavaIdentifierStart (pValue.charAt (0))) { return false; } else { for (int i = 1; i < len; i++) { if (!Character.isJavaIdentifierPart (pValue.charAt (i))) { return false; } } return true; } } } //------------------------------------- // Expression methods //------------------------------------- /** * * Returns the expression in the expression language syntax **/ public String getExpressionString () { return toStringToken ((String) getValue ()); } //------------------------------------- }