/*
* Copyright 2008 Google 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.google.gwt.user.rebind;
import com.google.gwt.core.client.GWT;
import com.google.gwt.core.client.RunAsyncCallback;
import com.google.gwt.core.ext.Generator;
import com.google.gwt.core.ext.GeneratorContext;
import com.google.gwt.core.ext.TreeLogger;
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.JPrimitiveType;
import com.google.gwt.core.ext.typeinfo.JType;
import com.google.gwt.core.ext.typeinfo.TypeOracle;
import com.google.gwt.user.client.AsyncProxy;
import com.google.gwt.user.client.AsyncProxy.AllowNonVoid;
import com.google.gwt.user.client.AsyncProxy.ConcreteType;
import com.google.gwt.user.client.AsyncProxy.DefaultValue;
import com.google.gwt.user.client.impl.AsyncProxyBase;
import java.io.PrintWriter;
import java.util.Arrays;
import java.util.Iterator;
/**
* Generates implementation of AsyncProxy interfaces.
*/
public class AsyncProxyGenerator extends Generator {
public String generate(TreeLogger logger, GeneratorContext generatorContext,
String typeName) throws UnableToCompleteException {
// The TypeOracle knows about all types in the type system
TypeOracle typeOracle = generatorContext.getTypeOracle();
// Get a reference to the type that the generator should implement
JClassType asyncProxyType = typeOracle.findType(AsyncProxy.class.getName());
JClassType asyncProxyBaseType = typeOracle.findType(AsyncProxyBase.class.getName());
JClassType sourceType = typeOracle.findType(typeName);
// Ensure that the requested type exists
if (sourceType == null) {
logger.log(TreeLogger.ERROR, "Could not find requested typeName");
throw new UnableToCompleteException();
} else if (sourceType.isInterface() == null) {
// The incoming type wasn't a plain interface, we don't support
// abstract base classes
logger.log(TreeLogger.ERROR, sourceType.getQualifiedSourceName()
+ " is not an interface.", null);
throw new UnableToCompleteException();
}
JClassType concreteType = getConcreteType(logger, typeOracle, sourceType);
JClassType paramType = getParamType(logger, asyncProxyType, sourceType);
validate(logger, sourceType, concreteType, paramType);
// com.foo.Bar$Proxy -> com_foo_Bar_ProxyImpl
String generatedSimpleSourceName = sourceType.getQualifiedSourceName().replace(
'.', '_').replace('$', '_')
+ "Impl";
// Begin writing the generated source.
ClassSourceFileComposerFactory f = new ClassSourceFileComposerFactory(
sourceType.getPackage().getName(), generatedSimpleSourceName);
String createdClassName = f.getCreatedClassName();
// The generated class needs to be able to determine the module base URL
f.addImport(GWT.class.getName());
f.addImport(RunAsyncCallback.class.getName());
// Used by the map methods
f.setSuperclass(asyncProxyBaseType.getQualifiedSourceName() + "<"
+ paramType.getQualifiedSourceName() + ">");
// The whole point of this exercise
f.addImplementedInterface(sourceType.getQualifiedSourceName());
// All source gets written through this Writer
PrintWriter out = generatorContext.tryCreate(logger,
sourceType.getPackage().getName(), generatedSimpleSourceName);
// If an implementation already exists, we don't need to do any work
if (out != null) {
SourceWriter sw = f.createSourceWriter(generatorContext, out);
// The invocation of runAsync, with a unique class for the split point
sw.println("protected void doAsync0() {");
sw.indent();
sw.println("GWT.runAsync(new RunAsyncCallback() {");
sw.indentln("public void onFailure(Throwable caught) {doFailure0(caught);}");
sw.indentln("public void onSuccess() {setInstance0(doCreate0());}");
sw.println("});");
sw.outdent();
sw.println("}");
// Field for callback, plus getter and setter
String proxyCallback = "ProxyCallback<"
+ paramType.getQualifiedSourceName() + ">";
sw.println("private " + proxyCallback + " callback;");
sw.println("public void setProxyCallback(" + proxyCallback
+ " callback) {this.callback = callback;}");
sw.println("protected " + proxyCallback
+ " getCallback0() {return callback;}");
// doCreate0() method to invoke GWT.create()
sw.println("private " + paramType.getQualifiedSourceName()
+ " doCreate0() {");
sw.indent();
sw.println("return GWT.create(" + concreteType.getQualifiedSourceName()
+ ".class);");
sw.outdent();
sw.println("}");
boolean allowNonVoid = sourceType.getAnnotation(AllowNonVoid.class) != null;
for (JMethod method : paramType.getOverridableMethods()) {
DefaultValue defaults = getDefaultValue(sourceType, method);
if (method.getReturnType() != JPrimitiveType.VOID && !allowNonVoid) {
logger.log(TreeLogger.ERROR, "The method " + method.getName()
+ " returns a type other than void, but "
+ sourceType.getQualifiedSourceName() + " does not define the "
+ AllowNonVoid.class.getSimpleName() + " annotation.");
throw new UnableToCompleteException();
}
// Print the method decl
sw.print("public " + method.getReturnType().getQualifiedSourceName()
+ " " + method.getName() + "(");
for (Iterator<JParameter> i = Arrays.asList(method.getParameters()).iterator(); i.hasNext();) {
JParameter param = i.next();
sw.print("final " + param.getType().getQualifiedSourceName() + " "
+ param.getName());
if (i.hasNext()) {
sw.print(", ");
}
}
sw.println(") {");
{
sw.indent();
// Try a direct dispatch if we have a proxy instance
sw.println("if (getProxiedInstance() != null) {");
{
sw.indent();
if (method.getReturnType() != JPrimitiveType.VOID) {
sw.print("return ");
}
writeInvocation(sw, "getProxiedInstance()", method);
sw.outdent();
}
// Otherwise queue up a parameterized command object
sw.println("} else {");
{
sw.indent();
sw.println("enqueue0(new ParamCommand<"
+ paramType.getQualifiedSourceName() + ">() {");
{
sw.indent();
sw.println("public void execute("
+ paramType.getQualifiedSourceName() + " t) {");
{
sw.indent();
writeInvocation(sw, "t", method);
sw.outdent();
}
sw.println("}");
sw.outdent();
}
sw.println("});");
if (method.getReturnType() != JPrimitiveType.VOID) {
sw.println("return "
+ getDefaultExpression(defaults, method.getReturnType())
+ ";");
}
sw.outdent();
}
sw.println("}");
sw.outdent();
}
sw.println("}");
}
sw.commit(logger);
}
// Return the name of the concrete class
return createdClassName;
}
private JClassType getConcreteType(TreeLogger logger, TypeOracle typeOracle,
JClassType sourceType) throws UnableToCompleteException {
JClassType concreteType;
ConcreteType concreteTypeAnnotation = sourceType.getAnnotation(ConcreteType.class);
if (concreteTypeAnnotation == null) {
logger.log(TreeLogger.ERROR, "AsnycProxy subtypes must specify a "
+ ConcreteType.class.getSimpleName() + " annotation.");
throw new UnableToCompleteException();
}
String concreteTypeName = concreteTypeAnnotation.value().getName().replace(
'$', '.');
concreteType = typeOracle.findType(concreteTypeName);
if (concreteType == null) {
logger.log(TreeLogger.ERROR,
"Unable to find concrete type; is it in the GWT source path?");
throw new UnableToCompleteException();
}
return concreteType;
}
/**
* Returns a useful default expression for a type. It is an error to pass
* JPrimitiveType.VOID into this method.
*/
private String getDefaultExpression(DefaultValue defaultValue, JType type) {
if (!(type instanceof JPrimitiveType)) {
return "null";
} else if (type == JPrimitiveType.BOOLEAN) {
return String.valueOf(defaultValue.booleanValue());
} else if (type == JPrimitiveType.BYTE) {
return String.valueOf(defaultValue.byteValue());
} else if (type == JPrimitiveType.CHAR) {
return String.valueOf((int) defaultValue.charValue());
} else if (type == JPrimitiveType.DOUBLE) {
return String.valueOf(defaultValue.doubleValue());
} else if (type == JPrimitiveType.FLOAT) {
return String.valueOf(defaultValue.floatValue()) + "F";
} else if (type == JPrimitiveType.INT) {
return String.valueOf(defaultValue.intValue());
} else if (type == JPrimitiveType.LONG) {
return String.valueOf(defaultValue.longValue());
} else if (type == JPrimitiveType.SHORT) {
return String.valueOf(defaultValue.shortValue());
} else if (type == JPrimitiveType.VOID) {
assert false : "Should not pass VOID into this method";
}
assert false : "Should never reach here";
return null;
}
private DefaultValue getDefaultValue(JClassType sourceType, JMethod method) {
DefaultValue toReturn = method.getAnnotation(DefaultValue.class);
if (toReturn == null) {
toReturn = sourceType.getAnnotation(DefaultValue.class);
}
if (toReturn == null) {
JClassType proxyType = sourceType.getOracle().findType(
AsyncProxy.class.getName());
toReturn = proxyType.getAnnotation(DefaultValue.class);
}
assert toReturn != null : "Could not find any DefaultValue instance";
return toReturn;
}
private JClassType getParamType(TreeLogger logger, JClassType asyncProxyType,
JClassType sourceType) throws UnableToCompleteException {
JClassType paramType = null;
for (JClassType intr : sourceType.getImplementedInterfaces()) {
JParameterizedType isParameterized = intr.isParameterized();
if (isParameterized == null) {
continue;
}
if (isParameterized.getBaseType().equals(asyncProxyType)) {
paramType = isParameterized.getTypeArgs()[0];
break;
}
}
if (paramType == null) {
logger.log(TreeLogger.ERROR, "Unable to determine parameterization type.");
throw new UnableToCompleteException();
}
return paramType;
}
private void validate(TreeLogger logger, JClassType sourceType,
JClassType concreteType, JClassType paramType)
throws UnableToCompleteException {
// sourceType may not define any methods
if (sourceType.getMethods().length > 0) {
logger.log(TreeLogger.ERROR,
"AsyncProxy subtypes may not define any additional methods");
throw new UnableToCompleteException();
}
// Make sure that sourceType implements paramType to assignments work
if (!sourceType.isAssignableTo(paramType)) {
logger.log(TreeLogger.ERROR, "Expecting "
+ sourceType.getQualifiedSourceName() + " to implement "
+ paramType.getQualifiedSourceName());
throw new UnableToCompleteException();
}
// Make sure that concreteType is assignable to paramType
if (!concreteType.isAssignableTo(paramType)) {
logger.log(TreeLogger.ERROR, "Expecting concrete type"
+ concreteType.getQualifiedSourceName() + " to implement "
+ paramType.getQualifiedSourceName());
throw new UnableToCompleteException();
}
// Must be able to GWT.create()
if (concreteType.isMemberType() && !concreteType.isStatic()) {
logger.log(TreeLogger.ERROR, "Expecting concrete type "
+ concreteType.getQualifiedSourceName() + " to be static.");
throw new UnableToCompleteException();
}
}
/**
* Given a method and a qualifier expression, construct an invocation of the
* method using its default parameter names.
*/
private void writeInvocation(SourceWriter sw, String qualifier, JMethod method) {
sw.print(qualifier + "." + method.getName() + "(");
for (Iterator<JParameter> i = Arrays.asList(method.getParameters()).iterator(); i.hasNext();) {
JParameter param = i.next();
sw.print(param.getName());
if (i.hasNext()) {
sw.print(", ");
}
}
sw.println(");");
}
}