| /******************************************************************************* |
| * Copyright (c) 2001, 2005 IBM Corporation and others. |
| * All rights reserved. This program and the accompanying materials |
| * are made available under the terms of the Eclipse Public License v2.0 |
| * which accompanies this distribution, and is available at |
| * https://www.eclipse.org/legal/epl-2.0/ |
| * |
| * Contributors: |
| * IBM Corporation - initial API and implementation |
| *******************************************************************************/ |
| package org.eclipse.jem.internal.proxy.initParser; |
| /* |
| |
| |
| */ |
| |
| |
| import java.util.*; |
| /** |
| * Insert the type's description here. |
| * Creation date: (11/01/00 8:46:44 PM) |
| * @author: Administrator |
| */ |
| public abstract class Expression implements IParserConstants { |
| protected Expression currentExpression; |
| protected List fExpressionStack; |
| protected ClassLoader fClassLoader; |
| public int parenthesisLevel = 0; |
| /** Compare the two char arrays |
| */ |
| public static boolean compare(char[] from , char[] to){ |
| |
| return Arrays.equals(from, to); |
| } |
| /** |
| * Expression constructor comment. |
| * Note: If any exceptions that are due to evaluation, and not due to some |
| * invalid state, then the exception should be wrappered in an EvaluationException, |
| * and the EvaluationException thrown instead. This way we can distinquish between |
| * valid exceptions that result evaluations (such as null pointer exceptions) from |
| * parser errors due to string is too complicated. |
| */ |
| public abstract Object evaluate() throws Exception; |
| |
| public abstract boolean isComplete(); |
| /** |
| * Return a class type that the expression syntactically would produce. |
| * For example, if a field is of type XYZ, return XYZ, even though |
| * the value of the field may be SubXYZ where SubXYZ is a subclass of XYZ. |
| */ |
| public abstract Class getTypeClass() throws Exception; |
| /** |
| * In evaluation phase, get the type class from the expression. |
| * If typeclass not found, then a ClassCastException is thrown. |
| * @param exp To getTypeClass from |
| * @return type class. |
| * @throws Exception ClassNotFoundException if type not found. |
| */ |
| public Class getEvaluationTypeClass(Expression exp) throws Exception { |
| Class cls = exp.getTypeClass(); |
| if (cls == null) |
| throw new EvaluationException(new ClassNotFoundException(exp.getTypeClassName())); |
| return cls; |
| } |
| |
| /** |
| * @return Type name that should be returned from this expression. |
| */ |
| protected abstract String getTypeClassName(); |
| |
| public boolean isNumber(char[] token){ |
| |
| if ( token.length == 0) return false; |
| // See whether the token is a number |
| int parsePosition = 0; |
| // Take into account it may start with a - sign, e.g. -1 |
| if ( token[0] == '-' ) parsePosition = 1; |
| for (int i = parsePosition; i < token.length ; i++){ |
| // If the next token is a digit return true |
| // Other things like decimals or primitive types, e.g. 2.2 or 2.2f are |
| // handled by NumberLiteral |
| return Character.isDigit(token[i]); |
| } |
| return true; |
| } |
| public boolean isPop(){ |
| return false; |
| } |
| protected void popExpressionStack(){ |
| |
| if ( fExpressionStack != null && fExpressionStack.size() > 0 ) { |
| currentExpression = (Expression) fExpressionStack.remove(fExpressionStack.size()-1); |
| } |
| } |
| protected void pushExpressionStack(Expression anExpression){ |
| |
| if ( fExpressionStack == null ) fExpressionStack = new ArrayList(2); |
| // The current expression should go onto the stack |
| fExpressionStack.add(currentExpression); |
| // The current expression is replaced with the argument |
| currentExpression = anExpression; |
| |
| } |
| |
| void setClassLoader(ClassLoader aClassLoader){ |
| } |
| |
| /** |
| * Push an expression onto us |
| * Return the new expression onto which subsequent token should be pushed |
| */ |
| public abstract Expression push(char[] token , char tokenDelimiter); |
| |
| /** |
| * Answer if this expression results in a primitive. |
| */ |
| public abstract boolean isPrimitive() throws Exception; |
| |
| public String toString(int depth, boolean aBreak){ |
| StringBuffer buffer = new StringBuffer(); |
| if ( aBreak ) { |
| buffer.append(System.getProperty("System.lineSeparator")); //$NON-NLS-1$ |
| } |
| for(int i=0;i<depth;i++){ |
| buffer.append(" "); //$NON-NLS-1$ |
| } |
| buffer.append(toString()); |
| return buffer.toString(); |
| } |
| } |