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    
015    package org.apache.tapestry5.services;
016    
017    import org.apache.tapestry5.Binding;
018    import org.apache.tapestry5.ComponentResources;
019    import org.apache.tapestry5.ioc.Location;
020    import 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)
027    public 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    }