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
015package org.apache.tapestry.binding;
016
017import org.apache.hivemind.Location;
018import org.apache.tapestry.IBinding;
019import org.apache.tapestry.IComponent;
020
021/**
022 * Used to convert a binding string (from a template or a specification) into an instance of
023 * {@link IBinding}.
024 * 
025 * @since 4.0
026 */
027public interface BindingSource
028{
029    /**
030     * Creates a new binding. The locator is used to identify the <em>type</em> of binding to
031     * create as well as configure the binding instance. The locator is either a literal value
032     * (resulting in a {@link org.apache.tapestry.binding.LiteralBinding literal binding}) or
033     * consists of prefix and a path, i.e., <code>ognl:myProperty</code>.
034     * <p>
035     * When a prefix exists and is identified, it is used to select the correct
036     * {@link BindingFactory}, and the remainder of the path (i.e., <code>myProperty</code)
037     * is passed to the factory.  An unrecognized prefix is treated as a literal value
038     * (it is often "javascript:" or "http:", etc.).
039     * 
040     * @param component the component for which the binding is created; the component is used
041     * as a kind of context for certain types of bindings (for example, the root object when
042     * evaluating OGNL expressions).
043     * @param description {@link IBinding#getDescription() description} for the new binding
044     * @param reference the binding reference used to create the binding, possibly including a prefix to define the type.
045     * If the reference does not include a prefix, then  the defaultBindingType is used as the prefix
046     * @param defaultbindingType binding type to use when no prefix is provided in the reference
047     * or doesn't match a known binding factory.
048     * @param location location used to report errors in the binding
049     */
050    public IBinding createBinding(IComponent component, String description, String reference,
051            String defaultBindingType, Location location);
052}