| /** |
| * 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.hcatalog.data.schema; |
| |
| import java.io.Serializable; |
| import java.util.ArrayList; |
| import java.util.Collections; |
| import java.util.HashMap; |
| import java.util.List; |
| import java.util.Map; |
| |
| import org.apache.hcatalog.common.HCatException; |
| |
| /** |
| * HCatSchema. This class is NOT thread-safe. |
| */ |
| |
| public class HCatSchema implements Serializable { |
| |
| private static final long serialVersionUID = 1L; |
| |
| private final List<HCatFieldSchema> fieldSchemas; |
| private final Map<String, Integer> fieldPositionMap; |
| private final List<String> fieldNames; |
| |
| /** |
| * |
| * @param fieldSchemas is now owned by HCatSchema. Any subsequent modifications |
| * on fieldSchemas won't get reflected in HCatSchema. Each fieldSchema's name |
| * in the list must be unique, otherwise throws IllegalArgumentException. |
| */ |
| public HCatSchema(final List<HCatFieldSchema> fieldSchemas) { |
| this.fieldSchemas = new ArrayList<HCatFieldSchema>(fieldSchemas); |
| int idx = 0; |
| fieldPositionMap = new HashMap<String, Integer>(); |
| fieldNames = new ArrayList<String>(); |
| for (HCatFieldSchema field : fieldSchemas) { |
| if (field == null) |
| throw new IllegalArgumentException("Field cannot be null"); |
| |
| String fieldName = field.getName(); |
| if (fieldPositionMap.containsKey(fieldName)) |
| throw new IllegalArgumentException("Field named " + fieldName + |
| " already exists"); |
| fieldPositionMap.put(fieldName, idx); |
| fieldNames.add(fieldName); |
| idx++; |
| } |
| } |
| |
| public void append(final HCatFieldSchema hfs) throws HCatException { |
| if (hfs == null) |
| throw new HCatException("Attempt to append null HCatFieldSchema in HCatSchema."); |
| |
| String fieldName = hfs.getName(); |
| if (fieldPositionMap.containsKey(fieldName)) |
| throw new HCatException("Attempt to append HCatFieldSchema with already " + |
| "existing name: " + fieldName + "."); |
| |
| this.fieldSchemas.add(hfs); |
| this.fieldNames.add(fieldName); |
| this.fieldPositionMap.put(fieldName, this.size() - 1); |
| } |
| |
| /** |
| * Users are not allowed to modify the list directly, since HCatSchema |
| * maintains internal state. Use append/remove to modify the schema. |
| */ |
| public List<HCatFieldSchema> getFields() { |
| return Collections.unmodifiableList(this.fieldSchemas); |
| } |
| |
| /** |
| * @param fieldName |
| * @return the index of field named fieldName in Schema. If field is not |
| * present, returns null. |
| */ |
| public Integer getPosition(String fieldName) { |
| return fieldPositionMap.get(fieldName); |
| } |
| |
| public HCatFieldSchema get(String fieldName) throws HCatException { |
| return get(getPosition(fieldName)); |
| } |
| |
| public List<String> getFieldNames() { |
| return this.fieldNames; |
| } |
| |
| public HCatFieldSchema get(int position) { |
| return fieldSchemas.get(position); |
| } |
| |
| public int size() { |
| return fieldSchemas.size(); |
| } |
| |
| public void remove(final HCatFieldSchema hcatFieldSchema) throws HCatException { |
| |
| if (!fieldSchemas.contains(hcatFieldSchema)) { |
| throw new HCatException("Attempt to delete a non-existent column from HCat Schema: " + hcatFieldSchema); |
| } |
| |
| fieldSchemas.remove(hcatFieldSchema); |
| fieldPositionMap.remove(hcatFieldSchema); |
| fieldNames.remove(hcatFieldSchema.getName()); |
| } |
| |
| @Override |
| public String toString() { |
| boolean first = true; |
| StringBuilder sb = new StringBuilder(); |
| for (HCatFieldSchema hfs : fieldSchemas) { |
| if (!first) { |
| sb.append(","); |
| } else { |
| first = false; |
| } |
| if (hfs.getName() != null) { |
| sb.append(hfs.getName()); |
| sb.append(":"); |
| } |
| sb.append(hfs.toString()); |
| } |
| return sb.toString(); |
| } |
| |
| public String getSchemaAsTypeString() { |
| boolean first = true; |
| StringBuilder sb = new StringBuilder(); |
| for (HCatFieldSchema hfs : fieldSchemas) { |
| if (!first) { |
| sb.append(","); |
| } else { |
| first = false; |
| } |
| if (hfs.getName() != null) { |
| sb.append(hfs.getName()); |
| sb.append(":"); |
| } |
| sb.append(hfs.getTypeString()); |
| } |
| return sb.toString(); |
| } |
| |
| @Override |
| public boolean equals(Object obj) { |
| if (this == obj) { |
| return true; |
| } |
| if (obj == null) { |
| return false; |
| } |
| if (!(obj instanceof HCatSchema)) { |
| return false; |
| } |
| HCatSchema other = (HCatSchema) obj; |
| if (!this.getFields().equals(other.getFields())) { |
| return false; |
| } |
| return true; |
| } |
| |
| @Override |
| public int hashCode() { |
| return toString().hashCode(); |
| } |
| } |