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
   * <p/>
   * http://www.apache.org/licenses/LICENSE-2.0
   * <p/>
   * 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.flink.streaming.siddhi.schema;
  
  import org.apache.flink.api.java.tuple.Tuple;
  import org.apache.flink.api.java.typeutils.TypeExtractor;
  import org.apache.flink.util.Preconditions;
  
  import java.io.Serializable;
  import java.lang.reflect.Field;
  
  /**
   * Stream Serialization and Field Extraction Methods.
   */
  public class StreamSerializer<T> implements Serializable {
      private final StreamSchema<T> schema;
  
      public StreamSerializer(StreamSchema<T> schema) {
          this.schema = schema;
      }
  
      public Object[] getRow(T input) {
          Preconditions.checkArgument(input.getClass() == schema.getTypeInfo().getTypeClass(),
              "Invalid input type: " + input + ", expected: " + schema.getTypeInfo());
  
          Object[] data;
          if (schema.isAtomicType()) {
              data = new Object[]{input};
          } else if (schema.isTupleType()) {
              Tuple tuple = (Tuple) input;
              data = new Object[schema.getFieldIndexes().length];
              for (int i = 0; i < schema.getFieldIndexes().length; i++) {
                  data[i] = tuple.getField(schema.getFieldIndexes()[i]);
              }
          } else if (schema.isPojoType() || schema.isCaseClassType()) {
              data = new Object[schema.getFieldIndexes().length];
              for (int i = 0; i < schema.getFieldNames().length; i++) {
                  data[i] = getFieldValue(schema.getFieldNames()[i], input);
              }
          } else {
              throw new IllegalArgumentException("Failed to get field values from " + schema.getTypeInfo());
          }
          return data;
      }
  
      private Object getFieldValue(String fieldName, T input) {
          // TODO: Cache Field Accessor
          Field field = TypeExtractor.getDeclaredField(schema.getTypeInfo().getTypeClass(), fieldName);
          if (field == null) {
              throw new IllegalArgumentException(fieldName + " is not found in " + schema.getTypeInfo());
          }
          if (!field.isAccessible()) {
              field.setAccessible(true);
          }
          try {
              return field.get(input);
          } catch (IllegalAccessException e) {
              throw new IllegalStateException(e.getMessage(), e);
          }
      }
  }
  