com.gwtplatform.dispatch.rest.rebind.RestActionGenerator Maven / Gradle / Ivy
/**
* Copyright 2013 ArcBees Inc.
*
* 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 com.gwtplatform.dispatch.rest.rebind;
import java.io.PrintWriter;
import java.lang.annotation.Annotation;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.List;
import javax.inject.Inject;
import javax.inject.Provider;
import javax.ws.rs.DELETE;
import javax.ws.rs.FormParam;
import javax.ws.rs.GET;
import javax.ws.rs.HEAD;
import javax.ws.rs.HeaderParam;
import javax.ws.rs.POST;
import javax.ws.rs.PUT;
import javax.ws.rs.Path;
import javax.ws.rs.PathParam;
import javax.ws.rs.QueryParam;
import org.apache.velocity.VelocityContext;
import org.apache.velocity.app.VelocityEngine;
import com.google.common.eventbus.EventBus;
import com.google.gwt.core.ext.UnableToCompleteException;
import com.google.gwt.core.ext.typeinfo.JClassType;
import com.google.gwt.core.ext.typeinfo.JMethod;
import com.google.gwt.core.ext.typeinfo.JParameter;
import com.google.gwt.core.ext.typeinfo.JParameterizedType;
import com.google.gwt.core.ext.typeinfo.JType;
import com.google.gwt.core.ext.typeinfo.NotFoundException;
import com.google.gwt.core.ext.typeinfo.TypeOracle;
import com.google.inject.assistedinject.Assisted;
import com.gwtplatform.dispatch.rest.rebind.event.RegisterMetadataEvent;
import com.gwtplatform.dispatch.rest.rebind.event.RegisterSerializableTypeEvent;
import com.gwtplatform.dispatch.rest.rebind.type.ActionBinding;
import com.gwtplatform.dispatch.rest.rebind.type.MethodCall;
import com.gwtplatform.dispatch.rest.rebind.util.AnnotationValueResolver;
import com.gwtplatform.dispatch.rest.rebind.util.FormParamValueResolver;
import com.gwtplatform.dispatch.rest.rebind.util.GeneratorUtil;
import com.gwtplatform.dispatch.rest.rebind.util.HeaderParamValueResolver;
import com.gwtplatform.dispatch.rest.rebind.util.PathParamValueResolver;
import com.gwtplatform.dispatch.rest.rebind.util.QueryParamValueResolver;
import com.gwtplatform.dispatch.rest.shared.HttpMethod;
import com.gwtplatform.dispatch.rest.shared.MetadataType;
import com.gwtplatform.dispatch.rest.shared.RestAction;
import static com.gwtplatform.dispatch.rest.shared.MetadataType.BODY_TYPE;
import static com.gwtplatform.dispatch.rest.shared.MetadataType.RESPONSE_TYPE;
public class RestActionGenerator extends AbstractVelocityGenerator {
private static class AnnotatedMethodParameter {
private JParameter parameter;
private String fieldName;
private AnnotatedMethodParameter(JParameter parameter, String fieldName) {
this.parameter = parameter;
this.fieldName = fieldName;
}
}
@SuppressWarnings("unchecked")
private static final List> PARAM_ANNOTATIONS =
Arrays.asList(HeaderParam.class, QueryParam.class, PathParam.class, FormParam.class);
private static final String TEMPLATE = "com/gwtplatform/dispatch/rest/rebind/RestAction.vm";
private static final String PATH_PARAM = "{%s}";
private static final String PATH_PARAM_MISSING = "@PathParam(\"%1$s\") declared, but '%1$s' not found in %2$s.";
private static final String MANY_REST_ANNOTATIONS = "'%s' parameter's '%s' is annotated with more than one REST " +
"annotations.";
private static final String MANY_POTENTIAL_BODY = "%s has more than one potential body parameter.";
private static final String FORM_AND_BODY_PARAM = "%s has both @FormParam and a body parameter. You must specify " +
"one or the other.";
private static final String ADD_HEADER_PARAM = "addHeaderParam";
private static final String ADD_PATH_PARAM = "addPathParam";
private static final String ADD_QUERY_PARAM = "addQueryParam";
private static final String ADD_FORM_PARAM = "addFormParam";
private static final String SET_BODY_PARAM = "setBodyParam";
private final EventBus eventBus;
private final JMethod actionMethod;
private final JType returnType;
private final List pathParams = new ArrayList();
private final List headerParams = new ArrayList();
private final List queryParams = new ArrayList();
private final List formParams = new ArrayList();
private final List potentialBodyParams = new ArrayList();
private HttpMethod httpMethod;
private String path = "";
private JParameter bodyParam;
@Inject
public RestActionGenerator(
EventBus eventBus,
TypeOracle typeOracle,
Logger logger,
Provider velocityContextProvider,
VelocityEngine velocityEngine,
GeneratorUtil generatorUtil,
@Assisted JMethod actionMethod) throws UnableToCompleteException {
super(typeOracle, logger, velocityContextProvider, velocityEngine, generatorUtil);
this.eventBus = eventBus;
this.actionMethod = actionMethod;
returnType = actionMethod.getReturnType();
}
public ActionBinding generate(String restServicePath) throws Exception {
verifyIsAction();
JClassType resultType = getResultType();
path = restServicePath;
retrieveConfigAnnotations();
retrieveParameterConfig();
retrieveBodyConfig();
verifyPathParamsExist();
String implName = getClassName();
PrintWriter printWriter = getGeneratorUtil().tryCreatePrintWriter(getPackage(), implName);
if (printWriter != null) {
mergeTemplate(printWriter, TEMPLATE, implName);
} else {
getLogger().debug("Action already generated. Returning.");
}
registerMetadata();
return new ActionBinding(implName, actionMethod.getName(), resultType.getParameterizedQualifiedSourceName(),
actionMethod.getParameters());
}
@Override
protected String getPackage() {
return actionMethod.getEnclosingType().getPackage().getName().replace(SHARED_PACKAGE, CLIENT_PACKAGE);
}
@Override
protected void populateVelocityContext(VelocityContext velocityContext) throws UnableToCompleteException {
velocityContext.put("resultClass", getResultType());
velocityContext.put("httpMethod", httpMethod);
velocityContext.put("methodCalls", getMethodCallsToAdd());
velocityContext.put("restPath", path);
velocityContext.put("ctorParams", actionMethod.getParameters());
}
private List getMethodCallsToAdd() {
List methodCalls = new ArrayList();
methodCalls.addAll(getMethodCallsToAdd(headerParams, ADD_HEADER_PARAM));
methodCalls.addAll(getMethodCallsToAdd(pathParams, ADD_PATH_PARAM));
methodCalls.addAll(getMethodCallsToAdd(queryParams, ADD_QUERY_PARAM));
methodCalls.addAll(getMethodCallsToAdd(formParams, ADD_FORM_PARAM));
if (bodyParam != null) {
methodCalls.add(new MethodCall(SET_BODY_PARAM, null, bodyParam));
}
return methodCalls;
}
private List getMethodCallsToAdd(List methodParameters,
String methodName) {
List methodCalls = new ArrayList();
for (AnnotatedMethodParameter methodParameter : methodParameters) {
methodCalls.add(new MethodCall(methodName, methodParameter.fieldName, methodParameter.parameter));
}
return methodCalls;
}
private void registerMetadata() throws Exception {
if (bodyParam != null) {
registerMetadatum(BODY_TYPE, bodyParam.getType());
}
registerMetadatum(RESPONSE_TYPE, getResultType());
}
private void registerMetadatum(MetadataType metadataType, JType type) {
String typeLiteral = "\"" + type.getParameterizedQualifiedSourceName() + "\"";
eventBus.post(new RegisterMetadataEvent(getQualifiedClassName(), metadataType, typeLiteral));
if (!Void.class.getCanonicalName().equals(type.getQualifiedSourceName())) {
eventBus.post(new RegisterSerializableTypeEvent(type));
}
}
private String getQualifiedClassName() {
return getPackage() + "." + getClassName();
}
private String getClassName() {
return getBaseName() + "_" + returnType.isClassOrInterface().getName() + SUFFIX;
}
private String getBaseName() {
StringBuilder nameBuilder = new StringBuilder(actionMethod.getName());
Character firstChar = Character.toUpperCase(nameBuilder.charAt(0));
nameBuilder.setCharAt(0, firstChar);
StringBuilder classNameBuilder = new StringBuilder();
classNameBuilder.append(actionMethod.getEnclosingType().getName())
.append("_")
.append(nameBuilder);
for (JType type : actionMethod.getErasedParameterTypes()) {
classNameBuilder.append("_").append(type.getSimpleSourceName());
}
return classNameBuilder.toString();
}
private void verifyIsAction() throws UnableToCompleteException {
JClassType actionClass = null;
try {
actionClass = getTypeOracle().getType(RestAction.class.getName());
} catch (NotFoundException e) {
getLogger().die("Unable to find interface Action.");
}
JClassType returnClass = returnType.isClassOrInterface();
if (!returnClass.isAssignableTo(actionClass)) {
String typeName = returnClass.getQualifiedSourceName();
getLogger().die(typeName + " must implement RestAction.");
}
}
private void retrieveConfigAnnotations() throws UnableToCompleteException {
retrieveHttpMethod();
if (actionMethod.isAnnotationPresent(Path.class)) {
path = concatenatePath(path, actionMethod.getAnnotation(Path.class).value());
}
}
private void retrieveHttpMethod() throws UnableToCompleteException {
Boolean moreThanOneAnnotation = false;
if (actionMethod.isAnnotationPresent(GET.class)) {
httpMethod = HttpMethod.GET;
}
if (actionMethod.isAnnotationPresent(POST.class)) {
moreThanOneAnnotation = httpMethod != null;
httpMethod = HttpMethod.POST;
}
if (actionMethod.isAnnotationPresent(PUT.class)) {
moreThanOneAnnotation = moreThanOneAnnotation || httpMethod != null;
httpMethod = HttpMethod.PUT;
}
if (actionMethod.isAnnotationPresent(DELETE.class)) {
moreThanOneAnnotation = moreThanOneAnnotation || httpMethod != null;
httpMethod = HttpMethod.DELETE;
}
if (actionMethod.isAnnotationPresent(HEAD.class)) {
moreThanOneAnnotation = moreThanOneAnnotation || httpMethod != null;
httpMethod = HttpMethod.HEAD;
}
if (httpMethod == null) {
getLogger().die(actionMethod.getName() + " has no http method annotations.");
} else if (moreThanOneAnnotation) {
getLogger().warn(actionMethod.getName() + " has more than one http method annotation.");
}
}
private void retrieveParameterConfig() throws UnableToCompleteException {
JParameter[] parameters = actionMethod.getParameters();
buildParamList(parameters, HeaderParam.class, new HeaderParamValueResolver(), headerParams);
buildParamList(parameters, PathParam.class, new PathParamValueResolver(), pathParams);
buildParamList(parameters, QueryParam.class, new QueryParamValueResolver(), queryParams);
buildParamList(parameters, FormParam.class, new FormParamValueResolver(), formParams);
buildPotentialBodyParams();
}
private void buildParamList(JParameter[] parameters, Class annotationClass,
AnnotationValueResolver annotationValueResolver,
List destination)
throws UnableToCompleteException {
List> restrictedAnnotations = getRestrictedAnnotations(annotationClass);
for (JParameter parameter : parameters) {
T parameterAnnotation = parameter.getAnnotation(annotationClass);
if (parameterAnnotation != null) {
if (hasAnnotationFrom(parameter, restrictedAnnotations)) {
getLogger().die(String.format(MANY_REST_ANNOTATIONS, actionMethod.getName(), parameter.getName()));
throw new UnableToCompleteException();
}
String value = annotationValueResolver.resolve(parameterAnnotation);
destination.add(new AnnotatedMethodParameter(parameter, value));
}
}
}
private List> getRestrictedAnnotations(Class allowedAnnotation) {
List> restrictedAnnotations = new ArrayList>();
restrictedAnnotations.addAll(PARAM_ANNOTATIONS);
restrictedAnnotations.remove(allowedAnnotation);
return restrictedAnnotations;
}
private Boolean hasAnnotationFrom(JParameter parameter, List> restrictedAnnotations) {
for (Class restrictedAnnotation : restrictedAnnotations) {
if (parameter.isAnnotationPresent(restrictedAnnotation)) {
return true;
}
}
return false;
}
private void buildPotentialBodyParams() {
Collections.addAll(potentialBodyParams, actionMethod.getParameters());
List annotatedParameters = new ArrayList();
annotatedParameters.addAll(headerParams);
annotatedParameters.addAll(pathParams);
annotatedParameters.addAll(queryParams);
annotatedParameters.addAll(formParams);
for (AnnotatedMethodParameter annotatedParameter : annotatedParameters) {
potentialBodyParams.remove(annotatedParameter.parameter);
}
}
private void verifyPathParamsExist() throws UnableToCompleteException {
for (AnnotatedMethodParameter param : pathParams) {
verifyPathParamExists(param.fieldName);
}
}
private void verifyPathParamExists(String param) throws UnableToCompleteException {
if (!path.contains(String.format(PATH_PARAM, param))) {
String warning = String.format(PATH_PARAM_MISSING, param, path);
getLogger().die(warning);
}
}
private void retrieveBodyConfig() throws UnableToCompleteException {
if (potentialBodyParams.isEmpty()) {
return;
}
if (potentialBodyParams.size() > 1) {
getLogger().die(String.format(MANY_POTENTIAL_BODY, actionMethod.getName()));
}
if (!formParams.isEmpty()) {
getLogger().die(String.format(FORM_AND_BODY_PARAM, actionMethod.getName()));
}
bodyParam = potentialBodyParams.get(0);
}
private JClassType getResultType() throws UnableToCompleteException {
JParameterizedType parameterized = returnType.isParameterized();
if (parameterized == null || parameterized.getTypeArgs().length != 1) {
getLogger().die("The action must specify a result type argument.");
}
return parameterized.getTypeArgs()[0];
}
}
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