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    
015    package org.apache.tapestry.binding;
016    
017    import org.apache.hivemind.Location;
018    import org.apache.tapestry.IBinding;
019    import 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     */
027    public 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    }