我正在尝试从Google数据存储区中的一种类型进行读取，并应用一些转换并写回另一种类型。我正在使用谷歌数据流来实现这一目标。从数据存储区读取数据时，我们可以给出Kind。但是在写作时无法给予善意。如何实现这一目标。
答案 0 :(得分：3)
编辑：糟糕，我刚刚注意到您要使用Java。 WriteToDatastore为我着眼于CreateEntityFn的Java等效物，在这种情况下，您必须在上一步中设置您的实体（包括种类）。在此示例中签出import apache_beam
from apache_beam.io.gcp.datastore.v1.datastoreio import WriteToDatastore
from google.cloud.proto.datastore.v1 import entity_pb2
from googledatastore import helper
class MakeEntity(object):
def __init__(self, project):
self._project = project
def make(self, element):
try:
entity = entity_pb2.Entity()
helper.add_key_path(entity.key, 'EntityKind', element['id'])
helper.add_properties(entity, {
"created": datetime.datetime.now(),
"email": unicode(element['email'],
"count": int(element['count'],
"amount": float(element['amount'],
})
return entity
except:
logging.error(traceback.format_exc())
raise
def build_pipeline(project, pipeline_options):
p = apache_beam.Pipeline(options=pipeline_options)
_ = \
(p
# other transforms
| 'create entity' >> apache_beam.Map(MakeEntity(project=project).make)
| 'write to datastore' >> WriteToDatastore(project=project))
return p
。 https://github.com/mbrukman/apache-beam/blob/master/examples/java/src/main/java/org/apache/beam/examples/cookbook/DatastoreWordCount.java#L197
原始：
这就是我的做法
public class ModifyEntityKindFn extends DoFn<Entity, Entity> {
@ProcessElement
public void processElement(ProcessContext context) {
Key.Builder keyBuilder = makeKey(NEW_KIND, inputEntity.getKey());
keyBuilder.getPartitionIdBuilder().setNamespaceId(NEW_NAMESPACE);
Entity.Builder entityBuilder = Entity.newBuilder().setKey(keyBuilder.build());
entityBuilder.getMutableProperties().put("content", makeValue(context.element()).build());
context.output(entityBuilder.build());
}
}
编辑＃2：：我调整了您的代码，使其更接近遵循我链接到的示例。希望这行得通
class WelcomeActivity: AppCompatActivity()
{
private lateinit var viewPager: ViewPager
private lateinit var myViewPagerAdapter: MyViewPagerAdapter
private lateinit var dotsLayout: LinearLayout
private lateinit var dots: Array<TextView>
private lateinit var layouts: IntArray
private lateinit var btnSkip: Button
private lateinit var btnNext: Button
val viewPagerPageChangeListener = object : ViewPager.OnPageChangeListener{
override fun onPageSelected(position: Int) {
addBottomDots(position)
// changing the next button text 'NEXT' / 'GOT IT'
if (position == layouts.size - 1) {
// last page. make button text to GOT IT
btnNext.text = "GOT IT"
btnSkip.visibility = View.GONE
} else {
// still pages are left
btnNext.text = "NEXT"
btnSkip.visibility = View.VISIBLE
}
}
override fun onPageScrolled(position: Int, positionOffset: Float, positionOffsetPixels: Int) {
TODO("not implemented")
}
override fun onPageScrollStateChanged(state: Int) {
TODO("not implemented")
}
}
private lateinit var prefManager: PrefManager
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
// Checking for first time launch - before calling setContentView()
prefManager = PrefManager(this)
if(!prefManager.isFirstTimeLaunch()){
launchHomeScreen()
finish()
}
if(Build.VERSION.SDK_INT >= 21){
window.decorView.systemUiVisibility = View.SYSTEM_UI_FLAG_LAYOUT_STABLE or View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN
}
setContentView(R.layout.activity_intro)
viewPager = view_pager
dotsLayout = layoutDots
btnSkip = btn_skip
btnNext = btn_next
// layouts of all welcome sliders
// add few more layouts if you want
layouts = intArrayOf(
R.layout.introslide1,
R.layout.introslide2,
R.layout.introslide3
)
// adding bottom dots
addBottomDots(0)
// making notification bar transparent
changeStatusBarColor()
myViewPagerAdapter = MyViewPagerAdapter()
viewPager.adapter = myViewPagerAdapter
viewPager.addOnPageChangeListener(viewPagerPageChangeListener)
btnSkip.setOnClickListener {launchHomeScreen()}
btnNext.setOnClickListener {
// checking for last page
// if last page home screen will be launched
val current: Int = getItem(+1)
if (current < layouts.size) {
// move to next screen
viewPager.currentItem = current
} else {
launchHomeScreen()
}
}
}
private fun addBottomDots(currentPage: Int){
dots = Array(layouts.size, {TextView(this)})
val colorsActive = resources.getIntArray(R.array.array_dot_active)
val colorsInactive = resources.getIntArray(R.array.array_dot_inactive)
dotsLayout.removeAllViews()
for(i in 0 until dots.size)
{
dots[i] = TextView(this)
dots[i].setText(Html.fromHtml("•")) // this function (Html.fromHtml) are deprecated
dots[i].textSize = 35.toFloat()
dots[i].setTextColor(colorsInactive[currentPage])
dotsLayout.addView(dots[i])
}
if(dots.size > 0)
dots[currentPage].setTextColor(colorsActive[currentPage])
}
private fun getItem(i: Int): Int{
return viewPager.currentItem + i
}
private fun launchHomeScreen(){
prefManager.setFirstTimeLaunch(false)
startActivity(Intent(this, MainActivity::class.java))
finish()
}
/**
* Making notification bar transparent
*/
private fun changeStatusBarColor(){
if(Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
this.window.addFlags(WindowManager.LayoutParams.FLAG_DRAWS_SYSTEM_BAR_BACKGROUNDS)
this.window.statusBarColor = Color.TRANSPARENT
}
}
/**
* View pager adapter
*/
inner class MyViewPagerAdapter: PagerAdapter() {
private lateinit var layoutInflater: LayoutInflater
override fun instantiateItem(container: ViewGroup, position: Int): Any {
layoutInflater = LayoutInflater.from(container.context)
val view: View = layoutInflater.inflate(layouts[position], container, false)
container.addView(view)
return view
}
override fun getCount(): Int{
return layouts.size
}
override fun isViewFromObject(view: View, obj: Any): Boolean {
return view == obj
}
override fun destroyItem(container: ViewGroup, position: Int, `object`: Any) {
val view: View = `object` as View
container.removeView(view)
}
}
}