com.google.gwt.inject.rebind.GinjectorGeneratorImpl Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of gin Show documentation

GIN (GWT INjection) brings automatic dependency injection to Google Web Toolkit client-side code. GIN is built on top of Guice and uses (a subset of) Guice's binding language.

There is a newer version: 2.1.2

Show newest version

/*
 * 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.inject.rebind;

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.inject.rebind.output.GinjectorImplOutputter;
import com.google.gwt.inject.rebind.reflect.NoSourceNameException;
import com.google.gwt.inject.rebind.reflect.ReflectUtil;
import com.google.inject.Inject;
import com.google.inject.Singleton;
import com.google.inject.TypeLiteral;

import java.io.PrintWriter;

/**
 * Does the heavy lifting involved in generating implementations of
 * {@link Ginjector}. This class is instantiated
 * once per class to generate, so it can keep useful state around in its fields.
 * (It is a singleton from Guice's perspective since we create a new
 * injector for each generation run.)
 */
@Singleton
class GinjectorGeneratorImpl {
  private final TreeLogger logger;
  private final GeneratorContext ctx;
  private final BindingsProcessor bindingsProcessor;
  private final GinjectorImplOutputter outputter;

  /**
   * Convenience cache of rootBindings.getGinjectorInterface().
   */
  private final TypeLiteral ginjectorInterface;

  /**
   * The bindings associated with the Ginjector to output.
   */
  private final GinjectorBindings rootBindings;

  @Inject
  public GinjectorGeneratorImpl(TreeLogger logger, GeneratorContext ctx,
      BindingsProcessor bindingsProcessor,
      @RootBindings GinjectorBindings rootBindings,
      GinjectorImplOutputter outputter) {
    this.logger = logger;
    this.ctx = ctx;
    this.bindingsProcessor = bindingsProcessor;
    this.ginjectorInterface = rootBindings.getGinjectorInterface();
    this.outputter = outputter;
    this.rootBindings = rootBindings;
  }

  public String generate() throws UnableToCompleteException {
    validateInjectorClass();

    Package interfacePackage = ginjectorInterface.getRawType().getPackage();
    String packageName = interfacePackage == null ? "" : interfacePackage.getName();
    String implClassName = getImplClassName();
    String generatedClassName = packageName + "." + implClassName;

    PrintWriter printWriter = ctx.tryCreate(logger, packageName, implClassName);
    if (printWriter == null) {
      // We've already created it, so nothing to do
    } else {
      bindingsProcessor.process();
      outputter.write(packageName, implClassName, printWriter, rootBindings);
    }

    return generatedClassName;
  }

  private String getImplClassName()
      throws UnableToCompleteException {
    try {
      return ReflectUtil.getSourceName(ginjectorInterface).replace(".", "_") + "Impl";
    } catch (NoSourceNameException e) {
      logger.log(TreeLogger.Type.ERROR, "Could not determine source name for ginjector", e);
      throw new UnableToCompleteException();
    }
  }

  private void validateInjectorClass()
      throws UnableToCompleteException {
    if (!ginjectorInterface.getRawType().isInterface()) {
      logger.log(TreeLogger.ERROR,
          ginjectorInterface.getRawType().getCanonicalName() + " is not an interface", null);
      throw new UnableToCompleteException();
    }
  }
}