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.IRender; 018 import org.apache.tapestry.form.IFormComponent; 019 020 /** 021 * Defines the interface for an object that tracks input fields. This interface 022 * is now poorly named, in that it tracks errors that may <em>not</em> be 023 * associated with a specific field. 024 * <p> 025 * For each field, a flag is stored indicating if the field is, in fact, in 026 * error. The input supplied by the client is stored so that if the form is 027 * re-rendered (as is typically done when there are input errors), the value 028 * entered by the user can be displayed back to the user. An error message 029 * renderer is stored; this is an object that can render the error message (it 030 * is usually a {@link org.apache.tapestry.valid.RenderString} wrapper 031 * around a simple string). 032 * 033 * @author Howard Lewis Ship 034 * @since 1.0.8 035 */ 036 037 public interface IFieldTracking 038 { 039 040 /** 041 * Returns true if the field is in error (that is, if it has an error 042 * message {@link #getErrorRenderer() renderer}. 043 */ 044 045 boolean isInError(); 046 047 /** 048 * Returns the field component. This may return null if the error is not 049 * associated with any particular field. Note: may return null after the 050 * field tracking object is serialized and deserialized (the underlying 051 * component reference is transient); this metehod is primarily used for 052 * testing. 053 */ 054 055 IFormComponent getComponent(); 056 057 /** 058 * Returns an object that will render the error message. The renderer 059 * <em>must</em> implement a simple <code>toString()</code> that does 060 * not produce markup, but is a simple message. 061 * 062 * @see ValidatorException#ValidatorException(String, IRender, 063 * ValidationConstraint) 064 * @since 1.0.9 065 */ 066 067 IRender getErrorRenderer(); 068 069 /** 070 * Returns the invalid input recorded for the field. This is stored so that, 071 * on a subsequent render, the smae invalid input can be presented to the 072 * client to be corrected. 073 */ 074 075 String getInput(); 076 077 /** 078 * Returns the name of the field, that is, the name assigned by the form 079 * (this will differ from the component's id when any kind of looping 080 * operation is in effect). 081 */ 082 083 String getFieldName(); 084 085 /** 086 * Returns the validation constraint that was violated by the input. This 087 * may be null if the constraint isn't known. 088 */ 089 090 ValidationConstraint getConstraint(); 091 }