/*
* 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.gadgets.rebind;
import com.google.gwt.core.client.GWT;
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.TypeOracle;
import com.google.gwt.gadgets.client.UserPreferences.Preference;
import com.google.gwt.gadgets.client.impl.PreferencesUtil;
import com.google.gwt.user.rebind.ClassSourceFileComposerFactory;
import com.google.gwt.user.rebind.SourceWriter;
import java.io.PrintWriter;
/**
* Provides a binding from a UserPreferences subtype to the Gadget container's
* preferences API.
*/
public class UserPreferencesGenerator extends Generator {
@Override
public String generate(TreeLogger logger, GeneratorContext context,
String typeName) throws UnableToCompleteException {
// The TypeOracle knows about all types in the type system
TypeOracle typeOracle = context.getTypeOracle();
// Get a reference to the type that the generator should implement
JClassType sourceType = typeOracle.findType(typeName);
// Ensure that the requested type exists
if (sourceType == null) {
logger.log(TreeLogger.ERROR, "Could not find requested typeName", null);
throw new UnableToCompleteException();
}
// Make sure the UserPreferences type is correctly defined
validateType(logger, sourceType);
// Pick a name for the generated class to not conflict.
String generatedSimpleSourceName = sourceType.getSimpleSourceName()
+ "UserPreferencesImpl";
// Begin writing the generated source.
ClassSourceFileComposerFactory f = new ClassSourceFileComposerFactory(
sourceType.getPackage().getName(), generatedSimpleSourceName);
f.addImport(GWT.class.getName());
f.addImport(PreferencesUtil.class.getName());
f.addImplementedInterface(typeName);
// All source gets written through this Writer
PrintWriter out = context.tryCreate(logger,
sourceType.getPackage().getName(), generatedSimpleSourceName);
// If an implementation already exists, we don't need to do any work
if (out != null) {
JClassType preferenceType = typeOracle.findType(Preference.class.getName().replace('$', '.'));
assert preferenceType != null;
// We really use a SourceWriter since it's convenient
SourceWriter sw = f.createSourceWriter(context, out);
for (JMethod m : sourceType.getOverridableMethods()) {
JClassType extendsPreferenceType = m.getReturnType().isClassOrInterface();
if (extendsPreferenceType == null
|| !preferenceType.isAssignableFrom(extendsPreferenceType)) {
logger.log(TreeLogger.ERROR, "Cannot assign "
+ extendsPreferenceType.getQualifiedSourceName() + " to "
+ preferenceType.getQualifiedSourceName(), null);
throw new UnableToCompleteException();
}
// private final FooProperty __propName = new FooProperty() {...}
sw.println("private final "
+ extendsPreferenceType.getParameterizedQualifiedSourceName()
+ " __" + m.getName() + " = ");
sw.indent();
writeInstantiation(logger, sw, extendsPreferenceType, m);
sw.println(";");
sw.outdent();
// public FooProperty property() { return __property; }
sw.print("public ");
sw.print(m.getReadableDeclaration(true, true, true, true, true));
sw.println("{");
sw.indent();
sw.println("return __" + m.getName() + ";");
sw.outdent();
sw.println("}");
}
sw.commit(logger);
}
return f.getCreatedClassName();
}
protected void validateType(TreeLogger logger, JClassType sourceType)
throws UnableToCompleteException {
if (sourceType.isInterface() == null) {
logger.log(TreeLogger.ERROR, "UserPreferences type must be interfaces",
null);
throw new UnableToCompleteException();
}
}
/**
* Write an instantiation expression for a given Preference subtype.
*/
protected void writeInstantiation(TreeLogger logger, SourceWriter sw,
JClassType extendsPreferenceType, JMethod prefMethod)
throws UnableToCompleteException {
PreferenceGenerator prefGenerator = GadgetUtils.getPreferenceGenerator(
logger, extendsPreferenceType);
prefGenerator.writeInstantiation(logger, sw, extendsPreferenceType,
prefMethod);
}
}