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With inspiration from other libraries
/*
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
*
* Copyright (c) 2012-2013 Oracle and/or its affiliates. All rights reserved.
*
* The contents of this file are subject to the terms of either the GNU
* General Public License Version 2 only ("GPL") or the Common Development
* and Distribution License("CDDL") (collectively, the "License"). You
* may not use this file except in compliance with the License. You can
* obtain a copy of the License at
* https://glassfish.dev.java.net/public/CDDL+GPL_1_1.html
* or packager/legal/LICENSE.txt. See the License for the specific
* language governing permissions and limitations under the License.
*
* When distributing the software, include this License Header Notice in each
* file and include the License file at packager/legal/LICENSE.txt.
*
* GPL Classpath Exception:
* Oracle designates this particular file as subject to the "Classpath"
* exception as provided by Oracle in the GPL Version 2 section of the License
* file that accompanied this code.
*
* Modifications:
* If applicable, add the following below the License Header, with the fields
* enclosed by brackets [] replaced by your own identifying information:
* "Portions Copyright [year] [name of copyright owner]"
*
* Contributor(s):
* If you wish your version of this file to be governed by only the CDDL or
* only the GPL Version 2, indicate your decision by adding "[Contributor]
* elects to include this software in this distribution under the [CDDL or GPL
* Version 2] license." If you don't indicate a single choice of license, a
* recipient has the option to distribute your version of this file under
* either the CDDL, the GPL Version 2 or to extend the choice of license to
* its licensees as provided above. However, if you add GPL Version 2 code
* and therefore, elected the GPL Version 2 license, then the option applies
* only if the new code is made subject to such option by the copyright
* holder.
*/
package org.glassfish.json;
import javax.json.*;
import javax.json.stream.JsonLocation;
import javax.json.stream.JsonParser;
import java.math.BigDecimal;
import java.util.*;
/**
* {@link JsonParser} implementation on top of JsonArray/JsonObject
*
* @author Jitendra Kotamraju
*/
class JsonStructureParser implements JsonParser {
private Scope current;
private Event state;
private final Deque scopeStack = new ArrayDeque();
JsonStructureParser(JsonArray array) {
current = new ArrayScope(array);
}
JsonStructureParser(JsonObject object) {
current = new ObjectScope(object);
}
@Override
public String getString() {
if (state == Event.KEY_NAME) {
return ((ObjectScope)current).key;
} else if (state == Event.VALUE_STRING) {
return ((JsonString)current.getJsonValue()).getString();
}
throw new IllegalStateException(JsonMessages.PARSER_GETSTRING_ERR(state));
}
@Override
public boolean isIntegralNumber() {
if (state == Event.VALUE_NUMBER) {
return ((JsonNumber)current.getJsonValue()).isIntegral();
}
throw new IllegalStateException(JsonMessages.PARSER_ISINTEGRALNUMBER_ERR(state));
}
@Override
public int getInt() {
if (state == Event.VALUE_NUMBER) {
return ((JsonNumber)current.getJsonValue()).intValue();
}
throw new IllegalStateException(JsonMessages.PARSER_GETINT_ERR(state));
}
@Override
public long getLong() {
if (state == Event.VALUE_NUMBER) {
return ((JsonNumber)current.getJsonValue()).longValue();
}
throw new IllegalStateException(JsonMessages.PARSER_GETLONG_ERR(state));
}
@Override
public BigDecimal getBigDecimal() {
if (state == Event.VALUE_NUMBER) {
return ((JsonNumber)current.getJsonValue()).bigDecimalValue();
}
throw new IllegalStateException(JsonMessages.PARSER_GETBIGDECIMAL_ERR(state));
}
@Override
public JsonLocation getLocation() {
return JsonLocationImpl.UNKNOWN;
}
@Override
public boolean hasNext() {
return !((state == Event.END_OBJECT || state == Event.END_ARRAY) && scopeStack.isEmpty());
}
@Override
public Event next() {
if (!hasNext()) {
throw new NoSuchElementException();
}
transition();
return state;
}
private void transition() {
if (state == null) {
state = current instanceof ArrayScope ? Event.START_ARRAY : Event.START_OBJECT;
} else {
if (state == Event.END_OBJECT || state == Event.END_ARRAY) {
current = scopeStack.pop();
}
if (current instanceof ArrayScope) {
if (current.hasNext()) {
current.next();
state = getState(current.getJsonValue());
if (state == Event.START_ARRAY || state == Event.START_OBJECT) {
scopeStack.push(current);
current = Scope.createScope(current.getJsonValue());
}
} else {
state = Event.END_ARRAY;
}
} else {
// ObjectScope
if (state == Event.KEY_NAME) {
state = getState(current.getJsonValue());
if (state == Event.START_ARRAY || state == Event.START_OBJECT) {
scopeStack.push(current);
current = Scope.createScope(current.getJsonValue());
}
} else {
if (current.hasNext()) {
current.next();
state = Event.KEY_NAME;
} else {
state = Event.END_OBJECT;
}
}
}
}
}
@Override
public void close() {
// no-op
}
private static Event getState(JsonValue value) {
switch (value.getValueType()) {
case ARRAY:
return Event.START_ARRAY;
case OBJECT:
return Event.START_OBJECT;
case STRING:
return Event.VALUE_STRING;
case NUMBER:
return Event.VALUE_NUMBER;
case TRUE:
return Event.VALUE_TRUE;
case FALSE:
return Event.VALUE_FALSE;
case NULL:
return Event.VALUE_NULL;
default:
throw new JsonException("Unknown value type="+value.getValueType());
}
}
private static abstract class Scope implements Iterator {
abstract JsonValue getJsonValue();
static Scope createScope(JsonValue value) {
if (value instanceof JsonArray) {
return new ArrayScope((JsonArray)value);
} else if (value instanceof JsonObject) {
return new ObjectScope((JsonObject)value);
}
throw new JsonException("Cannot be called for value="+value);
}
}
private static class ArrayScope extends Scope {
private final Iterator it;
private JsonValue value;
ArrayScope(JsonArray array) {
this.it = array.iterator();
}
@Override
public boolean hasNext() {
return it.hasNext();
}
@Override
public JsonValue next() {
value = it.next();
return value;
}
@Override
public void remove() {
throw new UnsupportedOperationException();
}
@Override
JsonValue getJsonValue() {
return value;
}
}
private static class ObjectScope extends Scope {
private final Iterator> it;
private JsonValue value;
private String key;
ObjectScope(JsonObject object) {
this.it = object.entrySet().iterator();
}
@Override
public boolean hasNext() {
return it.hasNext();
}
@Override
public Map.Entry next() {
Map.Entry next = it.next();
this.key = next.getKey();
this.value = next.getValue();
return next;
}
@Override
public void remove() {
throw new UnsupportedOperationException();
}
@Override
JsonValue getJsonValue() {
return value;
}
}
}