content: /*
   * Licensed to the Apache Software Foundation (ASF) under one
   * or more contributor license agreements.  See the NOTICE file
   * distributed with this work for additional information
   * regarding copyright ownership.  The ASF licenses this file
   * to you 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.apache.bookkeeper.metastore;
  
  import java.util.Set;
  import java.util.concurrent.CountDownLatch;
  import java.util.concurrent.TimeUnit;
  import org.apache.bookkeeper.metastore.MSException.Code;
  import org.apache.bookkeeper.versioning.Version;
  import org.apache.bookkeeper.versioning.Versioned;
  
  /**
   * Converts async calls to sync calls for MetastoreTable. Currently not
   * intended to be used other than for simple functional tests, however,
   * could be developed into a sync API.
   */
  public class MetastoreTableAsyncToSyncConverter {
  
      static class HeldValue<T> implements MetastoreCallback<T> {
          private CountDownLatch countDownLatch = new CountDownLatch(1);
          private int code;
          private T value = null;
  
          void waitCallback() throws MSException {
              try {
                  countDownLatch.await(10, TimeUnit.SECONDS);
              } catch (InterruptedException ie) {
                  Thread.currentThread().interrupt();
                  throw MSException.create(Code.InterruptedException);
              }
  
              if (Code.OK.getCode() != code) {
                  throw MSException.create(Code.get(code));
              }
          }
  
          public T getValue() {
              return value;
          }
  
          @Override
          public void complete(int rc, T value, Object ctx) {
              this.code = rc;
              this.value = value;
              countDownLatch.countDown();
          }
      }
  
      protected MetastoreTable table;
  
      public MetastoreTableAsyncToSyncConverter(MetastoreTable table) {
          this.table = table;
      }
  
      public Versioned<Value> get(String key) throws MSException {
          HeldValue<Versioned<Value>> retValue =
              new HeldValue<Versioned<Value>>();
  
          // make the actual async call
          this.table.get(key, retValue, null);
  
          retValue.waitCallback();
          return retValue.getValue();
      }
  
      public Versioned<Value> get(String key, Set<String> fields)
      throws MSException {
          HeldValue<Versioned<Value>> retValue =
              new HeldValue<Versioned<Value>>();
  
          // make the actual async call
          this.table.get(key, fields, retValue, null);
  
          retValue.waitCallback();
          return retValue.getValue();
      }
  
      public void remove(String key, Version version) throws MSException {
          HeldValue<Void> retValue = new HeldValue<Void>();
  
          // make the actual async call
          this.table.remove(key, version, retValue, null);
  
          retValue.waitCallback();
      }
  
      public Version put(String key, Value value, Version version)
      throws MSException {
          HeldValue<Version> retValue = new HeldValue<Version>();
  
          // make the actual async call
          this.table.put(key, value, version, retValue, null);
  
          retValue.waitCallback();
          return retValue.getValue();
      }
  
      public MetastoreCursor openCursor() throws MSException {
          HeldValue<MetastoreCursor> retValue = new HeldValue<MetastoreCursor>();
          // make the actual async call
          this.table.openCursor(retValue, null);
          retValue.waitCallback();
          return retValue.getValue();
      }
  
      public MetastoreCursor openCursor(Set<String> fields) throws MSException {
          HeldValue<MetastoreCursor> retValue = new HeldValue<MetastoreCursor>();
          // make the actual async call
          this.table.openCursor(fields, retValue, null);
          retValue.waitCallback();
          return retValue.getValue();
      }
  
  }
  