Struts example source code file (ExpressionValidator.java)

This example Struts source code file (ExpressionValidator.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Struts tags/keywords

boolean, boolean, exception, expressionvalidator, got, object, object, string, string, validation, validationexception, validationexception, validatorsupport

The Struts ExpressionValidator.java source code

/*
 * Copyright 2002-2006,2009 The Apache Software Foundation.
 * 
 * Licensed 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 com.opensymphony.xwork2.validator.validators;

import com.opensymphony.xwork2.validator.ValidationException;


/**
 * <!-- START SNIPPET: javadoc -->
 * A Non-Field Level validator that validates based on regular expression supplied.
 * <!-- END SNIPPET: javadoc -->
 * <p/>
 * 
 * <!-- START SNIPPET: parameters -->
 * <ul>
 * 	 <li>expression - the Ognl expression to be evaluated against the stack (Must evaluate to a Boolean)
 * </ul>
 * <!-- END SNIPPET: parameters -->
 *
 * 
 * <pre>
 * <!-- START SNIPPET: example -->
 *     <validators>
 *           <validator type="expression">
 *              <param name="expression"> .... </param>
 *              <message>Failed to meet Ognl Expression  .... </message>
 *           </validator>
 *     </validators>
 * <!-- END SNIPPET: example -->
 * </pre>
 *
 * @author Jason Carreira
 */
// START SNIPPET: global-level-validator
public class ExpressionValidator extends ValidatorSupport {

    private String expression;


    public void setExpression(String expression) {
        this.expression = expression;
    }

    public String getExpression() {
        return expression;
    }

    public void validate(Object object) throws ValidationException {
        Boolean answer = Boolean.FALSE;
        Object obj = null;

        try {
            obj = getFieldValue(expression, object);
        } catch (ValidationException e) {
            throw e;
        } catch (Exception e) {
            // let this pass, but it will be logged right below
        }

        if ((obj != null) && (obj instanceof Boolean)) {
            answer = (Boolean) obj;
        } else {
            log.warn("Got result of " + obj + " when trying to get Boolean.");
        }

        if (!answer.booleanValue()) {
            if (log.isDebugEnabled()) log.debug("Validation failed on expression " + expression + " with validated object "+ object);
            addActionError(object);
        }
    }
}
// END SNIPPET: global-level-validator