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/*
* Copyright (c) 2019 Oracle and/or its affiliates. All rights reserved.
*
* This program and the accompanying materials are made available under the
* terms of the Eclipse Public License v. 2.0 which is available at
* http://www.eclipse.org/legal/epl-2.0,
* or the Eclipse Distribution License v. 1.0 which is available at
* http://www.eclipse.org/org/documents/edl-v10.php.
*
* SPDX-License-Identifier: EPL-2.0 OR BSD-3-Clause
*/
package com.blazebit.persistence.integration.jsonb.jsonstructure;
import jakarta.json.JsonObject;
import jakarta.json.JsonValue;
import jakarta.json.bind.JsonbException;
import jakarta.json.stream.JsonParser;
import java.util.Iterator;
/**
* Iterates over {@link JsonObject} managing internal state.
*/
public class JsonObjectIterator extends JsonStructureIterator {
/**
* Location pointer.
*/
public enum State {
/**
* Start of the object.
*/
START,
/**
* Property key name.
*/
KEY,
/**
* Property value.
*/
VALUE,
/**
* End of the object.
*/
END
}
private final JsonObject jsonObject;
private final Iterator keyIterator;
private String currentKey;
private State state = State.START;
JsonObjectIterator(JsonObject jsonObject) {
this.jsonObject = jsonObject;
this.keyIterator = jsonObject.keySet().iterator();
}
private void nextKey() {
if (!keyIterator.hasNext()) {
throw new JsonbException("Object is empty");
}
currentKey = keyIterator.next();
}
@Override
public JsonParser.Event next() {
switch (state) {
case START:
if (keyIterator.hasNext()) {
nextKey();
setState(State.KEY);
return JsonParser.Event.KEY_NAME;
} else {
setState(State.END);
return JsonParser.Event.END_OBJECT;
}
case KEY:
setState(State.VALUE);
JsonValue value = getValue();
return getValueEvent(value);
case VALUE:
if (keyIterator.hasNext()) {
nextKey();
setState(State.KEY);
return JsonParser.Event.KEY_NAME;
}
setState(State.END);
return JsonParser.Event.END_OBJECT;
default:
throw new JsonbException("Illegal state");
}
}
@Override
public boolean hasNext() {
//From the perspective of JsonParser not finished until END_OBJECT is being read.
return state != State.END;
}
/**
* {@link JsonValue} for current key.
*
* @return Current JsonValue.
*/
public JsonValue getValue() {
return jsonObject.get(currentKey);
}
@Override
String getString() {
if (state == State.KEY) {
return currentKey;
}
return super.getString();
}
@Override
JsonbException createIncompatibleValueError() {
return new JsonbException("Incompatible value type [" + getValue().getValueType() + "] for key: " + currentKey);
}
private void setState(State state) {
this.state = state;
}
/**
* Current key this iterator is pointing at.
*
* @return Current key.
*/
public String getKey() {
return currentKey;
}
public JsonObject getJsonObject() {
return jsonObject;
}
}