    001    // Copyright 2007, 2008, 2009, 2010 The Apache Software Foundation
    002    //
    003    // Licensed under the Apache License, Version 2.0 (the "License");
    004    // you may not use this file except in compliance with the License.
    005    // You may obtain a copy of the License at
    006    //
    007    // http://www.apache.org/licenses/LICENSE-2.0
    008    //
    009    // Unless required by applicable law or agreed to in writing, software
    010    // distributed under the License is distributed on an "AS IS" BASIS,
    011    // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    012    // See the License for the specific language governing permissions and
    013    // limitations under the License.
    014
    015    package org.apache.tapestry5.internal;
    016
    017    import org.apache.tapestry5.*;
    018    import org.apache.tapestry5.dom.Element;
    019    import org.apache.tapestry5.services.Environment;
    020    import org.apache.tapestry5.services.FormSupport;
    021
    022    /**
    023     * Default implementation that writes an attribute into fields or labels that are in error.
    024     */
    025    public final class DefaultValidationDecorator extends BaseValidationDecorator
    026    {
    027        private final Environment environment;
    028
    029        private final Asset spacerAsset;
    030
    031        private final MarkupWriter markupWriter;
    032
    033        /**
    034         * @param environment
    035         *            used to locate objects and services during the render
    036         * @param spacerAsset
    037         *            asset for a one-pixel spacer image used as a placeholder for the error marker icon
    038         * @param markupWriter
    039         */
    040        public DefaultValidationDecorator(Environment environment, Asset spacerAsset, MarkupWriter markupWriter)
    041        {
    042            this.environment = environment;
    043            this.spacerAsset = spacerAsset;
    044            this.markupWriter = markupWriter;
    045        }
    046
    047        @Override
    048        public void insideField(Field field)
    049        {
    050            if (inError(field))
    051                addErrorClassToCurrentElement();
    052        }
    053
    054        @Override
    055        public void insideLabel(Field field, Element element)
    056        {
    057            if (field == null)
    058                return;
    059
    060            if (inError(field))
    061                element.addClassName(CSSClassConstants.ERROR);
    062        }
    063
    064        /**
    065         * Writes an icon for field after the field. The icon has the same id as the field, with ":icon" appended. This is
    066         * expected by the default client-side JavaScript. The icon's src is a blank spacer image (this is to allow the
    067         * image displayed to be overridden via CSS). The icon's CSS class is "t-error-icon", with "t-invisible" added
    068         * if the field is not in error when rendered. If client validation is not enabled for the form containing the
    069         * field and the field is not in error, then the error icon itself is not rendered.
    070         *
    071         * @param field
    072         *            which just completed rendering itself
    073         */
    074        @Override
    075        public void afterField(Field field)
    076        {
    077            boolean inError = inError(field);
    078
    079            boolean clientValidationEnabled = getFormSupport().isClientValidationEnabled();
    080
    081            if (inError || clientValidationEnabled)
    082            {
    083                String iconId = field.getClientId() + "_icon";
    084
    085                String cssClass = inError ? "t-error-icon" : "t-error-icon t-invisible";
    086
    087                markupWriter.element("img", "src", spacerAsset.toClientURL(), "alt", "", "class", cssClass, "id", iconId);
    088                markupWriter.end();
    089            }
    090
    091        }
    092
    093        private FormSupport getFormSupport()
    094        {
    095            return environment.peekRequired(FormSupport.class);
    096        }
    097
    098        private boolean inError(Field field)
    099        {
    100            ValidationTracker tracker = environment.peekRequired(ValidationTracker.class);
    101
    102            return tracker.inError(field);
    103        }
    104
    105        private void addErrorClassToCurrentElement()
    106        {
    107            markupWriter.getElement().addClassName(CSSClassConstants.ERROR);
    108        }
    109    }