Java tutorial
/* * Copyright 2014 Cask Data, Inc. * * 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 co.cask.cdap.hive.objectinspector; import com.google.common.collect.Lists; import com.google.common.primitives.Booleans; import com.google.common.primitives.Bytes; import com.google.common.primitives.Doubles; import com.google.common.primitives.Floats; import com.google.common.primitives.Ints; import com.google.common.primitives.Longs; import com.google.common.primitives.Shorts; import org.apache.hadoop.hive.serde2.objectinspector.ObjectInspector; import org.apache.hadoop.hive.serde2.objectinspector.SettableListObjectInspector; import java.util.ArrayList; import java.util.Collection; import java.util.Iterator; import java.util.List; /** * DefaultListObjectInspector works on list data that is stored as a Java List * or Java Array object. * * Always use the ObjectInspectorFactory to create new ObjectInspector objects, * instead of directly creating an instance of this class. */ public class StandardListObjectInspector implements SettableListObjectInspector { ObjectInspector listElementObjectInspector; /** * Call ObjectInspectorFactory.getStandardListObjectInspector instead. * Because of this protected constructor in the orignal Hive class, we cannot reuse it. */ protected StandardListObjectInspector(ObjectInspector listElementObjectInspector) { this.listElementObjectInspector = listElementObjectInspector; } public final Category getCategory() { return Category.LIST; } // without data public ObjectInspector getListElementObjectInspector() { return listElementObjectInspector; } // with data public Object getListElement(Object data, int index) { if (data == null) { return null; } // We support both List<Object>, Object[] and Collection<Object> // so we have to do differently. if (!(data instanceof List)) { if (data instanceof Collection) { Collection<?> collection = (Collection<?>) data; if (index < 0 || index >= collection.size()) { return null; } Iterator<?> ite = collection.iterator(); for (int i = 0; i < index; i++) { if (!ite.hasNext()) { return null; } ite.next(); } if (!ite.hasNext()) { return null; } return ite.next(); } else { List<?> list = getList(data); if (index < 0 || index >= list.size()) { return null; } return list.get(index); } } else { List<?> list = (List<?>) data; if (index < 0 || index >= list.size()) { return null; } return list.get(index); } } public int getListLength(Object data) { if (data == null) { return -1; } // We support both List<Object>, Object[] and Collection<Object> // so we have to do differently. if (!(data instanceof List)) { if (data instanceof Collection) { return ((Collection) data).size(); } else { List<?> list = getList(data); return list.size(); } } else { List<?> list = (List<?>) data; return list.size(); } } public List<?> getList(Object data) { if (data == null) { return null; } // We support List<Object>, Object[], and Collection<Object> // so we have to do differently. if (!(data instanceof List)) { if (data instanceof Collection) { data = Lists.newArrayList((Collection<?>) data); } else if (data instanceof Object[]) { data = java.util.Arrays.asList((Object[]) data); } else if (data instanceof byte[]) { data = Bytes.asList((byte[]) data); } else if (data instanceof int[]) { data = Ints.asList((int[]) data); } else if (data instanceof double[]) { data = Doubles.asList((double[]) data); } else if (data instanceof float[]) { data = Floats.asList((float[]) data); } else if (data instanceof short[]) { data = Shorts.asList((short[]) data); } else if (data instanceof long[]) { data = Longs.asList((long[]) data); } else if (data instanceof boolean[]) { data = Booleans.asList((boolean[]) data); } else { throw new UnsupportedOperationException("Data object is neither a Collection nor an array."); } } List<?> list = (List<?>) data; return list; } public String getTypeName() { return org.apache.hadoop.hive.serde.serdeConstants.LIST_TYPE_NAME + "<" + listElementObjectInspector.getTypeName() + ">"; } // ///////////////////////////// // SettableListObjectInspector @Override public Object create(int size) { List<Object> a = new ArrayList<>(size); for (int i = 0; i < size; i++) { a.add(null); } return a; } @Override public Object resize(Object list, int newSize) { if (!(list instanceof List) && (list instanceof Collection)) { // NOTE: no use-case should enter this statement, // because the list comes from the create method // but it's better to be safe than sorry. list = Lists.newArrayList((Collection<?>) list); } List<Object> a = (List<Object>) list; while (a.size() < newSize) { a.add(null); } while (a.size() > newSize) { a.remove(a.size() - 1); } // Return the modified list, but the list param will not be modified return a; } @Override public Object set(Object list, int index, Object element) { if (!(list instanceof List) && (list instanceof Collection)) { // NOTE: no use-case should enter this statement, // because the list comes from the create method // but it's better to be safe than sorry. list = Lists.newArrayList((Collection<?>) list); } List<Object> a = (List<Object>) list; a.set(index, element); // Return the modified list, but the list param will not be modified return a; } }