001// Copyright 2006, 2007, 2008 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.services;
016
017import org.apache.tapestry5.Binding;
018import org.apache.tapestry5.ComponentResources;
019import org.apache.tapestry5.ioc.Location;
020import org.apache.tapestry5.ioc.annotations.UsesMappedConfiguration;
021
022/**
023 * Used to acquire bindings for component parameters. The BindingSource service strips off the binding prefix to locate
024 * a {@link org.apache.tapestry5.services.BindingFactory}.
025 */
026@UsesMappedConfiguration(BindingFactory.class)
027public interface BindingSource
028{
029    /**
030     * Examines the expression and strips off the leading prefix. The prefix is used to choose the appropriate {@link
031     * BindingFactory}, which receives the description, the expression (after the prefix), and the location. If the
032     * prefix doesn't exist, or if there's no prefix, then the factory for the default prefix (often "literal") is used
033     * (and passed the full prefix).
034     * <p/>
035     * The binding represents a connection between the container and the component (the component is usually the child
036     * of the container, though in a few cases, it is the component itself). In most cases, the expression is evaluated
037     * in terms of the resources of the <em>container</em> and the component is ignored.
038     *
039     * @param description   description of the binding, such as "parameter foo"
040     * @param container     typically, the parent of the component
041     * @param component     the component whose parameter is to be bound
042     * @param defaultPrefix the default prefix used when the expression itself does not have a prefix
043     * @param expression    the binding
044     * @param location      location assigned to the binding (or null if not known)
045     * @return a binding
046     */
047    Binding newBinding(String description, ComponentResources container, ComponentResources component,
048                       String defaultPrefix, String expression, Location location);
049
050    /**
051     * A simpler version of {@link #newBinding(String, ComponentResources, ComponentResources, String, String,
052     * Location)} that defaults the values for several parameters. This is used in most cases. The default binding
053     * prefix will be "prop". Most often, this is used to create a new default binding.
054     *
055     * @param description   description of the binding, such as "parameter foo"
056     * @param container     typically, the parent of the component. This value will be used as the container
057     *                      <em>and</em> the component, so whatever type of expression is evaluated, will be evaulated
058     *                      in terms of this component
059     * @param defaultPrefix the default prefix used when the expression itself does not have a prefix
060     * @param expression    the binding
061     * @return a binding
062     */
063    Binding newBinding(String description, ComponentResources container, String defaultPrefix, String expression);
064}