001//  Copyright 2007, 2008, 2009 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
015package org.apache.tapestry5;
016
017/**
018 * Constants for the built-in binding prefixes.  These are often used with the {@link
019 * org.apache.tapestry5.annotations.Parameter#defaultPrefix()} annotation attribute.
020 */
021public class BindingConstants
022{
023    /**
024     * Binding expression prefix used for literal strings.
025     */
026    public static final String LITERAL = "literal";
027    /**
028     * Binding expression prefix used to bind to a property of the component. When {@link
029     * org.apache.tapestry5.annotations.Parameter#defaultPrefix()} is not specified, the default is PROP.
030     */
031    public static final String PROP = "prop";
032
033    /**
034     * A way of selecting a named {@link org.apache.tapestry5.NullFieldStrategy} contributed to {@link
035     * org.apache.tapestry5.services.NullFieldStrategySource}.
036     */
037    public static final String NULLFIELDSTRATEGY = "nullfieldstrategy";
038
039    /**
040     * A reference to a component within the container's template, by local component id.
041     */
042    public static final String COMPONENT = "component";
043
044    /**
045     * A reference to a localized message from the component's message catalog (including message keys inherited from
046     * the application global message catalog).
047     */
048    public static final String MESSAGE = "message";
049
050    /**
051     * References (and configures) one ore more named {@link org.apache.tapestry5.Validator}s contributed to the {@link
052     * org.apache.tapestry5.services.FieldValidatorSource} service.
053     *
054     * @see org.apache.tapestry5.services.FieldValidatorSource
055     */
056    public static final String VALIDATE = "validate";
057
058    /**
059     * References a named {@link org.apache.tapestry5.Translator} contributed to the {@link
060     * org.apache.tapestry5.services.TranslatorSource} service. The binding is of type {@link
061     * org.apache.tapestry5.FieldTranslator}.
062     */
063    public static final String TRANSLATE = "translate";
064
065    /**
066     * References a named block within the template.
067     */
068    public static final String BLOCK = "block";
069
070    /**
071     * References a localized asset.  The asset will be relative to the component's class file, unless a prefix
072     * (typically, "context:") is used on the expression.    Typically, this is used for classpath assets relative to
073     * the component class, and {@link #CONTEXT} is used for context assets.
074     *
075     * @see org.apache.tapestry5.Asset
076     * @see org.apache.tapestry5.services.AssetSource
077     */
078    public static final String ASSET = "asset";
079
080    /**
081     * Allows for temporary storage of information during the render only (may not currently be used during form
082     * submission processing).  This is often used to store the current object iterated over by a {@link
083     * org.apache.tapestry5.corelib.components.Loop} component.
084     */
085    public static final String VAR = "var";
086
087    /**
088     * Binding factory for context assets specifically. The expression is the path from the root of the web
089     * application.
090     *
091     * @since 5.1.0.0
092     */
093    public static final String CONTEXT = "context";
094    
095
096    /**
097     * References a value of a symbol.
098     * 
099     * @since 5.2.0
100     */
101    public static final String SYMBOL = "symbol";
102}