src/com/google/android/droiddriver/DroidDriverBuilder.java

/*
 * Copyright (C) 2013 DroidDriver committers
 *
 * 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.android.droiddriver;

import android.app.Instrumentation;
import android.os.Build;

import com.google.android.droiddriver.exceptions.DroidDriverException;
import com.google.android.droiddriver.instrumentation.InstrumentationDriver;
import com.google.android.droiddriver.uiautomation.UiAutomationDriver;
import com.google.common.base.Preconditions;

/**
 * Builds DroidDriver instances.
 */
public class DroidDriverBuilder {
  public enum Implementation {
    ANY, INSTRUMENTATION, UI_AUTOMATION
  }

  private final Instrumentation instrumentation;
  private Implementation implementation;

  public DroidDriverBuilder(Instrumentation instrumentation) {
    this.instrumentation = Preconditions.checkNotNull(instrumentation);
  }

  public DroidDriver build() {
    if (implementation == null) {
      implementation = Implementation.ANY;
    }
    switch (implementation) {
      case INSTRUMENTATION:
        return new InstrumentationDriver(instrumentation);
      case UI_AUTOMATION:
        return getUiAutomationDriver();
      case ANY:
        if (hasUiAutomation()) {
          return getUiAutomationDriver();
        }
        return new InstrumentationDriver(instrumentation);
    }
    // should never reach here
    throw new DroidDriverException("Cannot build DroidDriver");
  }

  private boolean hasUiAutomation() {
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR2) {
      return true;
    }
    // TODO: remove after mr2 is released?
    // This is necessary because now mr2 build has ro.build.version.sdk=17
    try {
      instrumentation.getUiAutomation();
      return true;
    } catch (NoSuchMethodError e) {
      return false;
    }
  }

  private UiAutomationDriver getUiAutomationDriver() {
    if (!hasUiAutomation()) {
      throw new DroidDriverException("UI_AUTOMATION is not available below API 18");
    }
    if (instrumentation.getUiAutomation() == null) {
        throw new DroidDriverException(
                "uiAutomation==null: did you forget to set '-w' flag for 'am instrument'?");
    }
    return new UiAutomationDriver(instrumentation);
  }

  public DroidDriverBuilder use(Implementation implementation) {
    Preconditions.checkState(this.implementation == null,
        "Cannot set implementation more than once");
    this.implementation = Preconditions.checkNotNull(implementation);
    return this;
  }
}