JAXRSJavaInterfaceProcessor.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.apache.tuscany.sca.interfacedef.java.jaxrs;

import java.lang.annotation.Annotation;
import java.lang.reflect.Method;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import javax.ws.rs.DELETE;
import javax.ws.rs.GET;
import javax.ws.rs.HEAD;
import javax.ws.rs.HttpMethod;
import javax.ws.rs.OPTIONS;
import javax.ws.rs.POST;
import javax.ws.rs.PUT;

import org.apache.tuscany.sca.interfacedef.InvalidInterfaceException;
import org.apache.tuscany.sca.interfacedef.Operation;
import org.apache.tuscany.sca.interfacedef.java.JavaInterface;
import org.apache.tuscany.sca.interfacedef.java.JavaOperation;
import org.apache.tuscany.sca.interfacedef.java.introspect.JavaInterfaceVisitor;

public class JAXRSJavaInterfaceProcessor implements JavaInterfaceVisitor {
    private static Map<String, Class<?>> mapping = new HashMap<String, Class<?>>();
    static {
        mapping.put(HttpMethod.GET, GET.class);
        mapping.put(HttpMethod.POST, POST.class);
        mapping.put(HttpMethod.PUT, PUT.class);
        mapping.put(HttpMethod.DELETE, DELETE.class);
        mapping.put(HttpMethod.HEAD, HEAD.class);
        mapping.put(HttpMethod.OPTIONS, OPTIONS.class);
    }

    private boolean introspectHTTPMethod(JavaOperation operation) {
        Method method = operation.getJavaMethod();

        String methodName = null;

        /**
         * A request method designator is a runtime annotation that is annotated with the @HttpMethod annotation.
         * JAX-RS defines a set of request method designators for the common HTTP methods: @GET, @POST, @PUT,
         * @DELETE, @HEAD. Users may define their own custom request method designators including alternate 
         * designators for the common HTTP methods.
         */
        for (Annotation a : method.getAnnotations()) {
            Class<?> annotationType = a.annotationType();
            if (annotationType == HttpMethod.class) {
                methodName = ((HttpMethod)a).value();
                break;
            }
            // Http method related annotations such as @GET, @POST will have itself annotated with
            // @HttpMethod
            HttpMethod m = a.annotationType().getAnnotation(HttpMethod.class);
            if (m != null) {
                methodName = m.value();
                break;
            }
        }

        boolean jaxrs = false;
        Class<?> type = mapping.get(methodName);
        if (type != null) {
            jaxrs = true;
            operation.getAttributes().put(type, Boolean.TRUE);
            Map<Object, Object> attrs = operation.getInterface().getAttributes();
            List<Operation> operations = (List<Operation>)attrs.get(type);
            if (operations == null) {
                operations = new ArrayList<Operation>();
                attrs.put(type, operations);
                operations.add(operation);
            } else {
                operations.add(operation);
            }
        }

        return jaxrs;

    }

    public void visitInterface(JavaInterface contract) throws InvalidInterfaceException {

        boolean hasJAXRSAnnotarions = false;

        for (Operation op : contract.getOperations()) {
            final JavaOperation operation = (JavaOperation)op;
            if (introspectHTTPMethod(operation)) {
                hasJAXRSAnnotarions = true;
            }
        }

        // Always set JAX-RS annotated interfaces as remotables
        if (hasJAXRSAnnotarions) {
            contract.setRemotable(true);
        }
    }
}