/* Copyright 2004-2005 Graeme Rocher
 *
 * 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 org.codehaus.groovy.grails.validation;

import org.springframework.validation.Errors;
import org.apache.commons.lang.StringUtils;

/**
 * A Constraint that validates a string is not blank
 *
 * @author Graeme Rocher
 * @since 0.4
 *        <p/>
 *        Created: Jan 19, 2007
 *        Time: 8:10:01 AM
 */
class BlankConstraint extends AbstractVetoingConstraint {

    private boolean blank;


    /* (non-Javadoc)
     * @see org.codehaus.groovy.grails.validation.Constraint#supports(java.lang.Class)
     */
    public boolean supports(Class type) {
        return type != null && String.class.isAssignableFrom(type);

    }

    public Object getParameter()
    {
        return Boolean.valueOf(blank);
    }

    /* (non-Javadoc)
     * @see org.codehaus.groovy.grails.validation.ConstrainedProperty.AbstractConstraint#setParameter(java.lang.Object)
     */
    public void setParameter(Object constraintParameter) {
        if(!(constraintParameter instanceof Boolean))
            throw new IllegalArgumentException("Parameter for constraint ["+ConstrainedProperty.BLANK_CONSTRAINT+"] of property ["+constraintPropertyName+"] of class ["+constraintOwningClass+"] must be a boolean value");

        this.blank = ((Boolean)constraintParameter).booleanValue();
        super.setParameter(constraintParameter);
    }

    public String getName() {
        return ConstrainedProperty.BLANK_CONSTRAINT;
    }

    protected boolean processValidateWithVetoing(Object target, Object propertyValue, Errors errors) {
        if(propertyValue instanceof String && StringUtils.isBlank((String)propertyValue)) {
            if(!blank) {
                Object[] args = new Object[] { constraintPropertyName, constraintOwningClass };
                super.rejectValue( target,errors, ConstrainedProperty.DEFAULT_BLANK_MESSAGE_CODE, ConstrainedProperty.BLANK_CONSTRAINT, args );
            }
            // empty string is catched by 'blank' constraint, no addition validation needed
            return true;
        }
        return false;
    }
}
