| /** |
| * 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 com.datatorrent.lib.appdata.schemas; |
| |
| import java.util.Collections; |
| import java.util.Map; |
| import java.util.Set; |
| |
| import org.codehaus.jettison.json.JSONArray; |
| import org.codehaus.jettison.json.JSONException; |
| import org.codehaus.jettison.json.JSONObject; |
| |
| import com.google.common.base.Preconditions; |
| import com.google.common.collect.Maps; |
| |
| import com.datatorrent.netlet.util.DTThrowable; |
| |
| /** |
| * This class represents an AppData snapshot schema. This class allows you to specify your |
| * snapshot schema in json and to load it. An example of a snapshot schema specification is the following: |
| * <br/> |
| * <br/> |
| * {@code |
| * { |
| * "values": [{"name": "hashtag", "type": "string"}, |
| * {"name": "count", "type": "integer"}] |
| * } |
| * } |
| * <br/> |
| * <br/> |
| * As can be seen above, the snapshot schema defines the name of each field which is served as well as |
| * its type. |
| * @since 3.0.0 |
| */ |
| public class SnapshotSchema implements Schema |
| { |
| /** |
| * The type of the schema. |
| */ |
| public static final String SCHEMA_TYPE = "snapshot"; |
| /** |
| * The version of the schema. |
| */ |
| public static final String SCHEMA_VERSION = "1.0"; |
| /** |
| * The type of the schema. |
| */ |
| public static final String FIELD_SCHEMA_TYPE = "schemaType"; |
| /** |
| * The version of the schema. |
| */ |
| public static final String FIELD_SCHEMA_VERSION = "schemaVersion"; |
| /** |
| * The JSON key string for the values section of the schema. |
| */ |
| public static final String FIELD_VALUES = "values"; |
| /** |
| * The JSON key string for field names. |
| */ |
| public static final String FIELD_VALUES_NAME = "name"; |
| /** |
| * The JSON key string for field types. |
| */ |
| public static final String FIELD_VALUES_TYPE = "type"; |
| |
| public static final int NUM_KEYS_FIRST_LEVEL = 1; |
| public static final int NUM_KEYS_VALUES = 2; |
| |
| /** |
| * The JSON for the schema. |
| */ |
| private String schemaJSON; |
| /** |
| * A map from the field name to its type. |
| */ |
| private Map<String, Type> valueToType; |
| /** |
| * The fieds descriptor object for the values. |
| */ |
| private FieldsDescriptor valuesDescriptor; |
| /** |
| * The schema keys for this schema. In the case where this is the only schema served by an operator, |
| * these could be null. |
| */ |
| private Map<String, String> schemaKeys; |
| /** |
| * The schemaID assigned to this schema. In the case where this is the only schema being served by an operator, |
| * then this is not important. |
| */ |
| private int schemaID = Schema.DEFAULT_SCHEMA_ID; |
| /** |
| * The JSONObject representing the schema. |
| */ |
| private JSONObject schema; |
| /** |
| * Flag indicating whether any items in the schema have been changed. |
| */ |
| private boolean changed = false; |
| |
| /** |
| * This creates a snapshot schema from the specified json with the specified schema keys. |
| * @param schemaJSON The JSON defining this schema. |
| * @param schemaKeys The schema keys tied to this schema. |
| */ |
| public SnapshotSchema(String schemaJSON, Map<String, String> schemaKeys) |
| { |
| this(schemaJSON); |
| |
| setSchemaKeys(schemaKeys); |
| } |
| |
| /** |
| * This creates a snapshot schema from the specified json with the specified schema keys, and |
| * schemaID. |
| * @param schemaID The ID associated with this schema. |
| * @param schemaJSON The schemaJSON this schema is built from. |
| * @param schemaKeys The schemaKeys associated with this schema. |
| */ |
| public SnapshotSchema(int schemaID, String schemaJSON, Map<String, String> schemaKeys) |
| { |
| this(schemaJSON, schemaKeys); |
| |
| this.schemaID = schemaID; |
| } |
| |
| /** |
| * This creates a snapshot schema from the specified json. |
| * @param schemaJSON The JSON specifying the snapshot schema. |
| */ |
| public SnapshotSchema(String schemaJSON) |
| { |
| setSchema(schemaJSON); |
| |
| try { |
| initialize(); |
| } catch (Exception ex) { |
| DTThrowable.rethrow(ex); |
| } |
| } |
| |
| /** |
| * This creates a snapshot schema from the specified json, and associates the given |
| * schemaID with this schema. |
| * @param schemaID The schemaID associated with this schema. |
| * @param schemaJSON The JSON that this schema is constructed from. |
| */ |
| public SnapshotSchema(int schemaID, String schemaJSON) |
| { |
| this(schemaJSON); |
| this.schemaID = schemaID; |
| } |
| |
| @Override |
| public final void setSchemaKeys(Map<String, String> schemaKeys) |
| { |
| changed = true; |
| |
| if (schemaKeys == null) { |
| this.schemaKeys = null; |
| return; |
| } |
| |
| for (Map.Entry<String, String> entry : schemaKeys.entrySet()) { |
| Preconditions.checkNotNull(entry.getKey()); |
| Preconditions.checkNotNull(entry.getValue()); |
| } |
| |
| this.schemaKeys = Collections.unmodifiableMap(Maps.newHashMap(schemaKeys)); |
| } |
| |
| /** |
| * This is a helper method to initialize the schema. |
| * @throws JSONException This exception is thrown if there is an error parsing the JSON |
| * which specified this schema. |
| */ |
| private void initialize() throws JSONException |
| { |
| schema = new JSONObject(schemaJSON); |
| |
| if (schemaKeys != null) { |
| schema.put(Schema.FIELD_SCHEMA_KEYS, SchemaUtils.createJSONObject(schemaKeys)); |
| } |
| |
| valueToType = Maps.newLinkedHashMap(); |
| |
| JSONArray values = schema.getJSONArray(FIELD_VALUES); |
| |
| Preconditions.checkState(values.length() > 0, |
| "The schema does not specify any values."); |
| |
| for (int index = 0; index < values.length(); index++) { |
| JSONObject value = values.getJSONObject(index); |
| String name = value.getString(FIELD_VALUES_NAME); |
| String typeName = value.getString(FIELD_VALUES_TYPE); |
| |
| Type type = Type.NAME_TO_TYPE.get(typeName); |
| valueToType.put(name, type); |
| |
| Preconditions.checkArgument(type != null, typeName + " is not a valid type."); |
| } |
| |
| valueToType = Collections.unmodifiableMap(valueToType); |
| valuesDescriptor = new FieldsDescriptor(valueToType); |
| |
| try { |
| schema.put(FIELD_SCHEMA_TYPE, SCHEMA_TYPE); |
| schema.put(FIELD_SCHEMA_VERSION, SCHEMA_VERSION); |
| } catch (JSONException e) { |
| throw new RuntimeException(e); |
| } |
| |
| schemaJSON = this.schema.toString(); |
| } |
| |
| public void setTags(Set<String> tags) |
| { |
| if (tags == null || tags.isEmpty()) { |
| throw new IllegalArgumentException("tags can't be null or empty."); |
| } |
| |
| try { |
| JSONArray tagArray = new JSONArray(tags); |
| |
| schema.put(FIELD_SCHEMA_TAGS, tagArray); |
| } catch (JSONException e) { |
| Preconditions.checkState(false, e.getMessage()); |
| throw new RuntimeException(e); |
| } |
| |
| schemaJSON = schema.toString(); |
| } |
| |
| /** |
| * This is a helper method which sets the JSON that represents this schema. |
| * @param schemaJSON The JSON that represents this schema. |
| */ |
| protected final void setSchema(String schemaJSON) |
| { |
| this.schemaJSON = Preconditions.checkNotNull(schemaJSON); |
| } |
| |
| @Override |
| public String getSchemaJSON() |
| { |
| if (!changed && schemaJSON != null) { |
| return schemaJSON; |
| } |
| |
| if (schemaKeys == null) { |
| schema.remove(Schema.FIELD_SCHEMA_KEYS); |
| } else { |
| try { |
| schema.put(Schema.FIELD_SCHEMA_KEYS, SchemaUtils.createJSONObject(schemaKeys)); |
| } catch (JSONException ex) { |
| throw new RuntimeException(ex); |
| } |
| } |
| |
| schemaJSON = schema.toString(); |
| return schemaJSON; |
| } |
| |
| @Override |
| public String getSchemaType() |
| { |
| return SCHEMA_TYPE; |
| } |
| |
| @Override |
| public String getSchemaVersion() |
| { |
| return SCHEMA_VERSION; |
| } |
| |
| /** |
| * Returns the {@link FieldsDescriptor} object which represents the values in this schema. |
| * @return The {@link FieldsDescriptor} object representing the values in this schema. |
| */ |
| public FieldsDescriptor getValuesDescriptor() |
| { |
| return valuesDescriptor; |
| } |
| |
| @Override |
| public Map<String, String> getSchemaKeys() |
| { |
| return schemaKeys; |
| } |
| |
| /** |
| * Gets the schemaID assigned to this schema. This is only relevant |
| * when an operator is hosting multiple schemas. |
| * @return The schemaID assigned to this schema. |
| */ |
| @Override |
| public int getSchemaID() |
| { |
| return schemaID; |
| } |
| } |