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/*
* 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.zeppelin.display;
import com.google.gson.Gson;
import org.apache.zeppelin.common.JsonSerializable;
import org.apache.zeppelin.scheduler.ExecutorFactory;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.util.LinkedList;
import java.util.List;
import java.util.Objects;
import java.util.concurrent.ExecutorService;
/**
* AngularObject provides binding between back-end (interpreter) and front-end
* User provided object will automatically synchronized with front-end side.
* i.e. update from back-end will be sent to front-end, update from front-end will sent-to backend
*
* @param
*/
public class AngularObject implements JsonSerializable {
private static final Logger LOGGER = LoggerFactory.getLogger(AngularObject.class);
private static final Gson GSON = new Gson();
private String name;
private T object;
private transient AngularObjectListener listener;
private transient List watchers = new LinkedList<>();
private String noteId; // noteId belonging to. null for global scope
private String paragraphId; // paragraphId belongs to. null for notebook scope
/**
* Public constructor, neccessary for the deserialization when using Thrift angularRegistryPush()
* Without public constructor, GSON library will instantiate the AngularObject using
* serialization so the watchers list won't be initialized and will throw
* NullPointerException the first time it is accessed
*/
public AngularObject() {
}
/**
* To create new AngularObject, use AngularObjectRegistry.add()
*
* @param name name of object
* @param o reference to user provided object to sent to front-end
* @param noteId noteId belongs to. can be null
* @param paragraphId paragraphId belongs to. can be null
* @param listener event listener
*/
public AngularObject(String name, T o, String noteId, String paragraphId,
AngularObjectListener listener) {
this.name = name;
this.noteId = noteId;
this.paragraphId = paragraphId;
this.listener = listener;
object = o;
}
/**
* Get name of this object
* @return name
*/
public String getName() {
return name;
}
/**
* Set noteId
* @param noteId noteId belongs to. can be null
*/
public void setNoteId(String noteId) {
this.noteId = noteId;
}
/**
* Get noteId
* @return noteId
*/
public String getNoteId() {
return noteId;
}
/**
* get ParagraphId
* @return paragraphId
*/
public String getParagraphId() {
return paragraphId;
}
/**
* Set paragraphId
* @param paragraphId paragraphId. can be null
*/
public void setParagraphId(String paragraphId) {
this.paragraphId = paragraphId;
}
/**
* Check if it is global scope object
* @return true it is global scope
*/
public boolean isGlobal() {
return noteId == null;
}
@Override
public boolean equals(Object o) {
if (this == o) return true;
if (o == null || getClass() != o.getClass()) return false;
AngularObject that = (AngularObject) o;
return Objects.equals(name, that.name) &&
Objects.equals(noteId, that.noteId) &&
Objects.equals(paragraphId, that.paragraphId);
}
@Override
public int hashCode() {
return Objects.hash(name, noteId, paragraphId);
}
/**
* Get value
* @return
*/
public Object get() {
return object;
}
/**
* fire updated() event for listener
* Note that it does not invoke watcher.watch()
*/
public void emit() {
if (listener != null) {
listener.updated(this);
}
}
/**
* Set value
* @param o reference to new user provided object
*/
public void set(T o) {
set(o, true);
}
/**
* Set value
* @param o reference to new user provided object
* @param emit false on skip firing event for listener. note that it does not skip invoke
* watcher.watch() in any case
*/
public void set(T o, boolean emit) {
final T before = object;
final T after = o;
object = o;
if (emit) {
emit();
}
LOGGER.debug("Update angular object: {} with value: {}", name, o);
final Logger logger = LoggerFactory.getLogger(AngularObject.class);
List ws = new LinkedList<>();
synchronized (watchers) {
ws.addAll(watchers);
}
ExecutorService executor = ExecutorFactory.singleton().createOrGet("angularObjectWatcher", 50);
for (final AngularObjectWatcher w : ws) {
executor.submit(new Runnable() {
@Override
public void run() {
try {
w.watch(before, after);
} catch (Exception e) {
logger.error("Exception on watch", e);
}
}
});
}
}
/**
* Set event listener for this object
* @param listener
*/
public void setListener(AngularObjectListener listener) {
this.listener = listener;
}
/**
* Get event listener of this object
* @return event listener
*/
public AngularObjectListener getListener() {
return listener;
}
/**
* Add a watcher for this object.
* Multiple watcher can be registered.
*
* @param watcher watcher to add
*/
public void addWatcher(AngularObjectWatcher watcher) {
synchronized (watchers) {
watchers.add(watcher);
}
}
/**
* Remove a watcher from this object
* @param watcher watcher to remove
*/
public void removeWatcher(AngularObjectWatcher watcher) {
synchronized (watchers) {
watchers.remove(watcher);
}
}
/**
* Remove all watchers from this object
*/
public void clearAllWatchers() {
synchronized (watchers) {
watchers.clear();
}
}
@Override
public String toString() {
final StringBuilder sb = new StringBuilder("AngularObject{");
sb.append("noteId='").append(noteId).append('\'');
sb.append(", paragraphId='").append(paragraphId).append('\'');
sb.append(", object=").append(object);
sb.append(", name='").append(name).append('\'');
sb.append('}');
return sb.toString();
}
@Override
public String toJson() {
return GSON.toJson(this);
}
public static AngularObject fromJson(String json) {
return GSON.fromJson(json, AngularObject.class);
}
}