Quelle ExpressionEvaluator.java Sprache: JAVA

/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package jakarta.servlet.jsp.el;

/**
* 
* The abstract base class for an expression-language evaluator. Classes that implement an expression language expose
* their functionality via this abstract class.
* 
* 
* An instance of the ExpressionEvaluator can be obtained via the JspContext / PageContext
* 
* 
* The parseExpression() and evaluate() methods must be thread-safe. That is, multiple threads may call these methods on
* the same ExpressionEvaluator object simultaneously. Implementations should synchronize access if they depend on
* transient state. Implementations should not, however, assume that only one object of each ExpressionEvaluator type
* will be instantiated; global caching should therefore be static.
* 
* 
* Only a single EL expression, starting with '${' and ending with '}', can be parsed or evaluated at a time. EL
* expressions cannot be mixed with static text. For example, attempting to parse or evaluate "
* <code>abc${1+1}def${1+1}ghi</code>" or even "<code>${1+1}${1+1}</code>" will cause an <code>ELException</code> to be
* thrown.
* 
* 
* The following are examples of syntactically legal EL expressions:
* 
* <ul>
* <li><code>${person.lastName}</code></li>
* <li><code>${8 * 8}</code></li>
* <li><code>${my:reverse('hello')}</code></li>
* </ul>
*
* @since JSP 2.0
*
* @deprecated As of JSP 2.1, replaced by jakarta.el.ExpressionFactory
*/
@Deprecated
public abstract class ExpressionEvaluator {

 /**
 * Prepare an expression for later evaluation. This method should perform syntactic validation of the expression; if
 * in doing so it detects errors, it should raise an ELParseException.
 *
 * @param expression The expression to be evaluated.
 * @param expectedType The expected type of the result of the evaluation
 * @param fMapper A FunctionMapper to resolve functions found in the expression. It can be null, in which case
 * no functions are supported for this invocation. The ExpressionEvaluator must not hold on
 * to the FunctionMapper reference after returning from <code>parseExpression()</code>. The
 * <code>Expression</code> object returned must invoke the same functions regardless of
 * whether the mappings in the provided <code>FunctionMapper</code> instance change between
 * calling <code>ExpressionEvaluator.parseExpression()</code> and
 * <code>Expression.evaluate()</code>.
 *
 * @return The Expression object encapsulating the arguments.
 *
 * @exception ELException Thrown if parsing errors were found.
 */
 public abstract Expression parseExpression(String expression, Class<?> expectedType, FunctionMapper fMapper)
 throws ELException;

 /**
 * Evaluates an expression. This method may perform some syntactic validation and, if so, it should raise an
 * ELParseException error if it encounters syntactic errors. EL evaluation errors should cause an ELException to be
 * raised.
 *
 * @param expression The expression to be evaluated.
 * @param expectedType The expected type of the result of the evaluation
 * @param vResolver A VariableResolver instance that can be used at runtime to resolve the name of implicit
 * objects into Objects.
 * @param fMapper A FunctionMapper to resolve functions found in the expression. It can be null, in which case
 * no functions are supported for this invocation.
 *
 * @return The result of the expression evaluation.
 *
 * @exception ELException Thrown if the expression evaluation failed.
 */
 public abstract Object evaluate(String expression, Class<?> expectedType, VariableResolver vResolver,
 FunctionMapper fMapper) throws ELException;
}

quality98%

¤ Dauer der Verarbeitung: 0.1 Sekunden (vorverarbeitet) ¤

Wurzel

Suchen

Beweissystem der NASA

Beweissystem Isabelle

NIST Cobol Testsuite

Cephes Mathematical Library

Wiener Entwicklungsmethode

Haftungshinweis

Die Informationen auf dieser Webseite wurden nach bestem Wissen sorgfältig zusammengestellt. Es wird jedoch weder Vollständigkeit, noch Richtigkeit, noch Qualität der bereit gestellten Informationen zugesichert.

Bemerkung:

Die farbliche Syntaxdarstellung ist noch experimentell.