/* 
    * 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 org.esigate.parser.future;
  
  import java.io.IOException;
  import java.util.ArrayList;
  import java.util.List;
  import java.util.concurrent.CancellationException;
  import java.util.concurrent.ExecutionException;
  import java.util.concurrent.Future;
  import java.util.concurrent.TimeUnit;
  import java.util.concurrent.TimeoutException;
  
  import org.esigate.HttpErrorPage;
  
  /**
   * This class is an Adapter for Appendable objects.
   * 
   * @author Nicolas Richeton
   * 
   */
  public class FutureAppendableAdapter implements FutureAppendable {
  
      private Appendable out;
      private List<Future<CharSequence>> futureList;
  
      public FutureAppendableAdapter(Appendable out) {
          this.out = out;
          this.futureList = new ArrayList<>();
      }
  
      @Override
      public FutureAppendable enqueueAppend(Future<CharSequence> csq) {
          this.futureList.add(csq);
          return this;
      }
  
      @Override
      public FutureAppendable performAppends(int timeout, TimeUnit unit) throws IOException, HttpErrorPage,
              TimeoutException {
  
          try {
              for (Future<CharSequence> f : this.futureList) {
                  CharSequence csq = f.get(timeout, unit);
                  this.out.append(csq);
              }
          } catch (CancellationException | InterruptedException e) {
              throw new IOException(e);
          } catch (ExecutionException e) {
              // HttpErrorPage must be
              if (e.getCause() instanceof HttpErrorPage) {
                  throw (HttpErrorPage) e.getCause();
              }
              throw new IOException(e);
          }
  
          this.futureList.clear();
          return this;
      }
  
      @Override
      public boolean hasPending() {
          return this.futureList.size() > 0;
      }
  
      @Override
      public FutureAppendable performAppends() throws IOException, HttpErrorPage {
          try {
              for (Future<CharSequence> f : this.futureList) {
                  CharSequence csq = f.get();
                  this.out.append(csq);
              }
          } catch (CancellationException | InterruptedException e) {
              throw new IOException(e);
          } catch (ExecutionException e) {
              // HttpErrorPage must be
              if (e.getCause() instanceof HttpErrorPage) {
                  throw (HttpErrorPage) e.getCause();
              }
              throw new IOException(e);
          }
  
          this.futureList.clear();
          return this;
      }
  }