001    // Copyright 2004, 2005 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.tapestry.valid;
016    
017    import org.apache.tapestry.IMarkupWriter;
018    import org.apache.tapestry.IRequestCycle;
019    import org.apache.tapestry.Tapestry;
020    import org.apache.tapestry.form.AbstractFormComponent;
021    import org.apache.tapestry.form.Form;
022    
023    /**
024     * A {@link Form}component that creates a text field that allows for validation
025     * of user input and conversion between string and object values.
026     * <p>
027     * A ValidatingTextField uses an {@link IValidationDelegate} to track errors and
028     * an {@link IValidator}to convert between strings and objects (as well as
029     * perform validations). The validation delegate is shared by all validating
030     * text fields in a form, the validator may be shared my multiple elements as
031     * desired.
032     * 
033     * @author Howard Lewis Ship
034     */
035    
036    public abstract class ValidField extends AbstractFormComponent
037    {
038    
039        public abstract boolean isHidden();
040    
041        public abstract boolean isDisabled();
042    
043        public abstract Object getValue();
044    
045        public abstract void setValue(Object value);
046    
047        /** Parameter. */
048    
049        public abstract String getDisplayName();
050    
051        /**
052         * @see org.apache.tapestry.form.AbstractFormComponent#renderFormComponent(org.apache.tapestry.IMarkupWriter,
053         *      org.apache.tapestry.IRequestCycle)
054         */
055        protected void renderFormComponent(IMarkupWriter writer, IRequestCycle cycle)
056        {
057            IValidationDelegate delegate = getForm().getDelegate();
058    
059            delegate.registerForFocus(this,
060                    delegate.isInError() ? ValidationConstants.ERROR_FIELD
061                            : ValidationConstants.NORMAL_FIELD);
062    
063            delegate.writePrefix(writer, cycle, this, null);
064    
065            writer.beginEmpty("input");
066    
067            writer.attribute("type", isHidden() ? "password" : "text");
068    
069            if (isDisabled()) writer.attribute("disabled", "disabled");
070    
071            writer.attribute("name", getName());
072    
073            String value = readValue();
074            if (value != null) writer.attribute("value", value);
075    
076            renderIdAttribute(writer, cycle);
077    
078            renderInformalParameters(writer, cycle);
079    
080            delegate.writeAttributes(writer, cycle, this, null);
081    
082            IValidator validator = getValidator();
083    
084            if (validator == null)
085                throw Tapestry.createRequiredParameterException(this, "validator");
086    
087            if (validator.isRequired())
088                delegate.registerForFocus(this, ValidationConstants.REQUIRED_FIELD);
089    
090            validator.renderValidatorContribution(this, writer, cycle);
091    
092            writer.closeTag();
093    
094            delegate.writeSuffix(writer, cycle, this, null);
095        }
096    
097        /**
098         * @see org.apache.tapestry.form.AbstractFormComponent#rewindFormComponent(org.apache.tapestry.IMarkupWriter,
099         *      org.apache.tapestry.IRequestCycle)
100         */
101        protected void rewindFormComponent(IMarkupWriter writer, IRequestCycle cycle)
102        {
103            String value = cycle.getParameter(getName());
104    
105            updateValue(value);
106        }
107    
108        protected String readValue()
109        {
110            IValidator validator = getValidator();
111            if (validator == null)
112                throw Tapestry.createRequiredParameterException(this, "validator");
113    
114            IValidationDelegate delegate = getForm().getDelegate();
115    
116            if (delegate.isInError()) return delegate.getFieldInputValue();
117    
118            Object value = getValue();
119    
120            String result = validator.toString(this, value);
121    
122            return result;
123        }
124    
125        protected void updateValue(String value)
126        {
127            Object objectValue = null;
128    
129            IValidator validator = getValidator();
130            if (validator == null)
131                throw Tapestry.createRequiredParameterException(this, "validator");
132    
133            IValidationDelegate delegate = getForm().getDelegate();
134    
135            delegate.recordFieldInputValue(value);
136    
137            try
138            {
139                objectValue = validator.toObject(this, value);
140            }
141            catch (ValidatorException ex)
142            {
143                delegate.record(ex);
144                return;
145            }
146    
147            setValue(objectValue);
148        }
149    
150        public abstract IValidator getValidator();
151    }