001// Licensed under the Apache License, Version 2.0 (the "License");
002// you may not use this file except in compliance with the License.
003// You may obtain a copy of the License at
004//
005//     http://www.apache.org/licenses/LICENSE-2.0
006//
007// Unless required by applicable law or agreed to in writing, software
008// distributed under the License is distributed on an "AS IS" BASIS,
009// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
010// See the License for the specific language governing permissions and
011// limitations under the License.
012
013package org.apache.tapestry5.services;
014
015import org.apache.tapestry5.Binding;
016import org.apache.tapestry5.ComponentResources;
017import org.apache.tapestry5.commons.Location;
018import org.apache.tapestry5.ioc.annotations.UsesMappedConfiguration;
019
020/**
021 * Used to acquire bindings for component parameters. The BindingSource service strips off the binding prefix to locate
022 * a {@link org.apache.tapestry5.services.BindingFactory}.
023 */
024@UsesMappedConfiguration(BindingFactory.class)
025public interface BindingSource
026{
027    /**
028     * Examines the expression and strips off the leading prefix. The prefix is used to choose the appropriate {@link
029     * BindingFactory}, which receives the description, the expression (after the prefix), and the location. If the
030     * prefix doesn't exist, or if there's no prefix, then the factory for the default prefix (often "literal") is used
031     * (and passed the full prefix).
032     *
033     * The binding represents a connection between the container and the component (the component is usually the child
034     * of the container, though in a few cases, it is the component itself). In most cases, the expression is evaluated
035     * in terms of the resources of the <em>container</em> and the component is ignored.
036     *
037     * @param description   description of the binding, such as "parameter foo"
038     * @param container     typically, the parent of the component
039     * @param component     the component whose parameter is to be bound
040     * @param defaultPrefix the default prefix used when the expression itself does not have a prefix
041     * @param expression    the binding
042     * @param location      location assigned to the binding (or null if not known)
043     * @return a binding
044     */
045    Binding newBinding(String description, ComponentResources container, ComponentResources component,
046                       String defaultPrefix, String expression, Location location);
047
048    /**
049     * A simpler version of {@link #newBinding(String, ComponentResources, ComponentResources, String, String,
050     * Location)} that defaults the values for several parameters. This is used in most cases. The default binding
051     * prefix will be "prop". Most often, this is used to create a new default binding.
052     *
053     * @param description   description of the binding, such as "parameter foo"
054     * @param container     typically, the parent of the component. This value will be used as the container
055     *                      <em>and</em> the component, so whatever type of expression is evaluated, will be evaulated
056     *                      in terms of this component
057     * @param defaultPrefix the default prefix used when the expression itself does not have a prefix
058     * @param expression    the binding
059     * @return a binding
060     */
061    Binding newBinding(String description, ComponentResources container, String defaultPrefix, String expression);
062}