Path.java

/*
 * Copyright 2013 cruxframework.org
 * 
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not
 * use this file except in compliance with the License. You may obtain a copy of
 * the License at
 * 
 * http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations under
 * the License.
 */
package org.cruxframework.crux.core.shared.rest.annotation;

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;


/**
 * Used to define the path that will be associated to a REST operation, or a class with operations.
 * <p>
 * See the following example:
 * <pre>
 * {@code @}{@link Path}("rest")
 * public class MyRestService{
 *    {@code @}{@link GET}
 *    {@code @}{@link Path}("test/{param1}")
 *    public String testOperation({@code @}PathParam("param1") String value) {
 *       return null;
 *    }
 * }
 * </pre>
 * </p>
 * <p>
 * The method testOperation will answer for requests done to the URI http://{@code <yourdomain>/<context>}/rest/test/{@code <anythingYouPassHere>} 
 * </p>
 *  
 * @author Thiago da Rosa de Bustamante
 *
 */
@Target({ElementType.TYPE, ElementType.METHOD})
@Retention(RetentionPolicy.RUNTIME)
public @interface Path {
    /**
     * Defines a URI template for the resource class or method, must not 
     * include matrix parameters.
     * 
     * <p>Embedded template parameters are allowed and are of the form:</p>
     * 
     * <pre> param = "{" *WSP name *WSP [ ":" *WSP regex *WSP ] "}"
     * name = (ALPHA / DIGIT / "_")*(ALPHA / DIGIT / "." / "_" / "-" ) ; \w[\w\.-]*
     * regex = *( nonbrace / "{" *nonbrace "}" ) ; where nonbrace is any char other than "{" and "}"</pre>
     * 
     * <p>See {@link <a href="http://tools.ietf.org/html/rfc5234">RFC 5234</a>} 
     * for a description of the syntax used above and the expansions of 
     * {@code WSP}, {@code ALPHA} and {@code DIGIT}. In the above {@code name}
     * is the template parameter name and the optional {@code regex} specifies 
     * the contents of the capturing group for the parameter. If {@code regex}
     * is not supplied then a default value of {@code [^/]+} which terminates at
     * a path segment boundary, is used. Matching of request URIs to URI 
     * templates is performed against encoded path values and implementations
     * will not escape literal characters in regex automatically, therefore any
     * literals in {@code regex} should be escaped by the author according to
     * the rules of
     * {@link <a href="http://tools.ietf.org/html/rfc3986#section-3.3">RFC 3986 section 3.3</a>}.
     * Caution is recommended in the use of {@code regex}, incorrect use can
     * lead to a template parameter matching unexpected URI paths. See 
     * {@link <a href="http://java.sun.com/j2se/1.5.0/docs/api/java/util/regex/Pattern.html">Pattern</a>}
     * for further information on the syntax of regular expressions.
     * Values of template parameters may be extracted using {@link PathParam}.
     *
     * <p>The literal part of the supplied value (those characters
     * that are not part of a template parameter) is automatically percent 
     * encoded to conform to the {@code path} production of 
     * {@link <a href="http://tools.ietf.org/html/rfc3986#section-3.3">RFC 3986 section 3.3</a>}.
     * Note that percent encoded values are allowed in the literal part of the
     * value, an implementation will recognize such values and will not double
     * encode the '%' character.</p>
     */
    String value();
    
}