| /* |
| * The Apache Software License, Version 1.1 |
| * |
| * Copyright (c) 2002-2003 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 acknowledgment: |
| * "This product includes software developed by the |
| * Apache Software Foundation (http://www.apache.org/)." |
| * Alternately, this acknowledgment may appear in the software itself, |
| * if and wherever such third-party acknowledgments normally appear. |
| * |
| * 4. The names "Xalan" and "Apache Software Foundation" must |
| * not be used to endorse or promote products derived from this |
| * software without prior written permission. For written |
| * permission, please contact apache@apache.org. |
| * |
| * 5. Products derived from this software may not be called "Apache", |
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| * permission of the Apache Software Foundation. |
| * |
| * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED |
| * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
| * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE |
| * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR |
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| * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT |
| * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
| * SUCH DAMAGE. |
| * ==================================================================== |
| * |
| * This software consists of voluntary contributions made by many |
| * individuals on behalf of the Apache Software Foundation and was |
| * originally based on software copyright (c) 2002, International |
| * Business Machines Corporation., http://www.ibm.com. For more |
| * information on the Apache Software Foundation, please see |
| * <http://www.apache.org/>. |
| */ |
| package org.apache.xpath.expression; |
| |
| /** |
| * Represents a XPath expression. |
| * <p>Use {@link #getExprType()} to query the expression type. |
| * More information about expression are obtained by casting it |
| * to its corresponding java type. Here the XPath expression type to Java type mapping table: |
| * </p> |
| * <table cellpadding="2" cellspacing="2" border="1"> |
| * <thead> |
| * <tr> |
| * <td>Expression type</td> |
| * <td>Java type</td> |
| * </tr> |
| * </thead> |
| * <tbody> |
| * <tr> |
| * <td>{@link #PATH_EXPR}</td> |
| * <td>{@link PathExpr}</td> |
| * </tr> |
| * <tr> |
| * <td>{@link #LOGICAL_EXPR}</td> |
| * <td>{@link OperatorExpr}</td> |
| * </tr> |
| * <tr> |
| * <td>{@link #CONDITIONAL_EXPR}</td> |
| * <td>{@link ConditionalExpr}</td> |
| * </tr> |
| * <tr> |
| * <td>{@link #ITERATION_EXPR}</td> |
| * <td>{@link ForAndQuantifiedExpr}</td> |
| * </tr> |
| * <tr> |
| * <td>{@link #EVERY_EXPR}</td> |
| * <td>{@link ForAndQuantifiedExpr}</td> |
| * </tr> |
| * <tr> |
| * <td>{@link #SOME_EXPR}</td> |
| * <td>{@link ForAndQuantifiedExpr}</td> |
| * </tr> |
| * <tr> |
| * <td>{@link #COMPARISON_EXPR}</td> |
| * <td>{@link OperatorExpr}</td> |
| * </tr> |
| * <tr> |
| * <td>{@link #ARITHMETIC_EXPR}</td> |
| * <td>{@link OperatorExpr}</td> |
| * </tr> |
| * <tr> |
| * <td>{@link #SEQUENCE_EXPR}</td> |
| * <td>{@link OperatorExpr}</td> |
| * </tr> |
| * <tr> |
| * <td>{@link #LITERAL_EXPR}</td> |
| * <td>{@link Literal}</td> |
| * </tr> |
| * <tr> |
| * <td>{@link #FUNCTION_CALL_EXPR}</td> |
| * <td>{@link FunctionCall}</td> |
| * </tr> |
| * <tr> |
| * <td>{@link #VARIABLE_REF_EXPR}</td> |
| * <td>{@link Variable}</td> |
| * </tr> |
| * <tr> |
| * <td>{@link #STEP}</td> |
| * <td>{@link StepExpr}</td> |
| * </tr> |
| * <tr> |
| * <td>{@link #INSTANCE_OF_EXPR}</td> |
| * <td>{@link InstanceOfExpr}</td> |
| * </tr> |
| * <tr> |
| * <td>{@link #UNARY_EXPR}</td> |
| * <td>{@link OperatorExpr}</td> |
| * </tr> |
| * <tr> |
| * <td>{@link #CAST_AS_EXPR}</td> |
| * <td>{@link CastOrTreatAsExpr}</td> |
| * </tr> |
| * <tr> |
| * <td>{@link #TREAT_AS_EXPR}</td> |
| * <td>{@link CastOrTreatAsExpr}</td> |
| * </tr> |
| * <tr> |
| * <td>{@link #CASTABLE_EXPR}</td> |
| * <td>{@link CastableAsExpr}</td> |
| * </tr> |
| * <tr> |
| * <td>{@link #VALIDATE_EXPR}</td> |
| * <td>{@link ?}</td> |
| * </tr> |
| * </tbody> |
| * </table> |
| * <p>For example the following code snippet may be used to get the items of |
| * the expression e = (1, call(),(toto[/user], $author)):</p> |
| * <pre> |
| * void printItem(Expr e) |
| * { |
| * if (e.getExprType() == Expr.SEQUENCE_EXPR) |
| * { |
| * OperatorExpr expr = (OperatorExpr) e; |
| * for (int i = 0; i %lt; expr.getOperandCount(); i ++ ) |
| * { |
| * printItem(expr.getOperand(i)); |
| * } |
| * } else |
| * { |
| * System.out.println(e.getString(true) + " "); |
| * } |
| * } |
| * </pre> |
| * <p>Should produced the following result:</p> |
| * <pre> |
| * 1 call() toto[/user] $author |
| * </pre> |
| * <p>XPath expressions are always fully expanded. For example, the expression |
| * /a//b is expanded to fn:root(self::node())/descendant-or-self::node()/b. |
| * The number of steps is 3 (and not 2). |
| * </p> |
| * <p> |
| * An {@link Expr} object may be not a valid XPath expression but only a fragment. |
| * For example a {@link StepExpr} expression is a fragment but can't be executed by |
| * itself. To be valid, the top level expression must be an expression sequence. |
| * </p> |
| * @see <a href="http://www.w3.org/TR/2002/WD-xpath20-20020816/#id-expressions">XPath 2.0 Specification</a> |
| * @author <a href="mailto:villard@us.ibm.com">Lionel Villard</a> |
| * @version $Id$ |
| */ |
| public interface Expr |
| { |
| |
| /** |
| * The expression is a path expression |
| */ |
| static final short PATH_EXPR = 0; |
| |
| /** |
| * The expression is a logical expression. |
| * Represents 'or' and 'and' expressions. |
| */ |
| static final short LOGICAL_EXPR = 1; |
| |
| /** |
| * The expression is a conditionnal expression (if) |
| */ |
| static final short CONDITIONAL_EXPR = 2; |
| |
| /** |
| * The expression is an iteration expression (for) |
| */ |
| static final short ITERATION_EXPR = 3; |
| |
| /** |
| * The expression is a quantified expression of type every |
| */ |
| static final short EVERY_EXPR = 4; |
| |
| /** |
| * The expression is a quantified expression of type some |
| */ |
| static final short SOME_EXPR = 22; |
| |
| /** |
| * The expression is a comparison expression type. |
| * Includes value comparisons, general comparisons, node comparisons |
| * and order comparisons. |
| */ |
| static final short COMPARISON_EXPR = 5; |
| |
| /** |
| * The expression is an arithmetic expression. |
| * Includes arithmetic operators for addition, subtraction, multiplication, division and modulus |
| */ |
| static final short ARITHMETIC_EXPR = 6; |
| |
| /** |
| * The expression is a sequence. |
| */ |
| static final short SEQUENCE_EXPR = 7; |
| |
| /** |
| * The expression is a validate expression |
| */ |
| static final short VALIDATE_EXPR = 10; |
| |
| /** |
| * The expression is a literal expression |
| */ |
| static final short LITERAL_EXPR = 13; |
| |
| /** |
| * The expression is a function call |
| */ |
| static final short FUNCTION_CALL_EXPR = 14; |
| |
| /** |
| * The expression is a variable reference |
| */ |
| static final short VARIABLE_REF_EXPR = 15; |
| |
| /** |
| * The expression is a step |
| */ |
| static final short STEP = 17; |
| |
| /** |
| * The expression is an instance of expression |
| */ |
| static final short INSTANCE_OF_EXPR = 18; |
| |
| /** |
| * The expression is a cast as expression |
| */ |
| static final short CAST_AS_EXPR = 20; |
| |
| /** |
| * The expression is a castable expression |
| */ |
| static final short CASTABLE_EXPR = 21; |
| |
| /** |
| * The expression is a treat as expression |
| */ |
| static final short TREAT_AS_EXPR = 22; |
| |
| /** |
| * The expression is a let expression |
| */ |
| static final short LET_EXPR = 23; |
| |
| |
| /** |
| * Gets the expression type. |
| * @return The type of this expression: one of the constants defined in this |
| * interface |
| */ |
| short getExprType(); |
| |
| /** |
| * Clone expression |
| * @return A clone of this expression |
| */ |
| Expr cloneExpression(); |
| |
| /** |
| * Gets the expression as a string (external form) |
| * @param abbreviate Gets the string as an abbreviate form or not |
| * @return The external form of this expression |
| */ |
| String getString(boolean abbreviate); |
| |
| /** |
| * Visit the expression. Pass through the expression hierarchy and |
| * invoke corresponding {@link Visitor callbacks}. |
| */ |
| boolean visit(Visitor visitor); |
| } |