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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 javax.json.stream.JsonParsingException;
import java.io.*;
import java.math.BigDecimal;
import java.nio.charset.Charset;
import java.util.*;
import org.glassfish.json.JsonTokenizer.JsonToken;
import org.glassfish.json.api.BufferPool;
/**
* JSON parser implementation. NoneContext, ArrayContext, ObjectContext is used
* to go to next parser state.
*
* @author Jitendra Kotamraju
*/
public class JsonParserImpl implements JsonParser {
private Context currentContext = new NoneContext();
private Event currentEvent;
private final Stack stack = new Stack();
private final StateIterator stateIterator;
private final JsonTokenizer tokenizer;
public JsonParserImpl(Reader reader, BufferPool bufferPool) {
tokenizer = new JsonTokenizer(reader, bufferPool);
stateIterator = new StateIterator();
}
public JsonParserImpl(InputStream in, BufferPool bufferPool) {
UnicodeDetectingInputStream uin = new UnicodeDetectingInputStream(in);
tokenizer = new JsonTokenizer(new InputStreamReader(uin, uin.getCharset()), bufferPool);
stateIterator = new StateIterator();
}
public JsonParserImpl(InputStream in, Charset encoding, BufferPool bufferPool) {
tokenizer = new JsonTokenizer(new InputStreamReader(in, encoding), bufferPool);
stateIterator = new StateIterator();
}
public String getString() {
if (currentEvent == Event.KEY_NAME || currentEvent == Event.VALUE_STRING
|| currentEvent == Event.VALUE_NUMBER) {
return tokenizer.getValue();
}
throw new IllegalStateException(
JsonMessages.PARSER_GETSTRING_ERR(currentEvent));
}
@Override
public boolean isIntegralNumber() {
if (currentEvent != Event.VALUE_NUMBER) {
throw new IllegalStateException(
JsonMessages.PARSER_ISINTEGRALNUMBER_ERR(currentEvent));
}
return tokenizer.isIntegral();
}
@Override
public int getInt() {
if (currentEvent != Event.VALUE_NUMBER) {
throw new IllegalStateException(
JsonMessages.PARSER_GETINT_ERR(currentEvent));
}
return tokenizer.getInt();
}
boolean isDefinitelyInt() {
return tokenizer.isDefinitelyInt();
}
@Override
public long getLong() {
if (currentEvent != Event.VALUE_NUMBER) {
throw new IllegalStateException(
JsonMessages.PARSER_GETLONG_ERR(currentEvent));
}
return tokenizer.getBigDecimal().longValue();
}
@Override
public BigDecimal getBigDecimal() {
if (currentEvent != Event.VALUE_NUMBER) {
throw new IllegalStateException(
JsonMessages.PARSER_GETBIGDECIMAL_ERR(currentEvent));
}
return tokenizer.getBigDecimal();
}
@Override
public JsonLocation getLocation() {
return tokenizer.getLocation();
}
public JsonLocation getLastCharLocation() {
return tokenizer.getLastCharLocation();
}
public boolean hasNext() {
return stateIterator.hasNext();
}
public Event next() {
return stateIterator.next();
}
private class StateIterator implements Iterator {
@Override
public boolean hasNext() {
if (stack.isEmpty() && (currentEvent == Event.END_ARRAY || currentEvent == Event.END_OBJECT)) {
JsonToken token = tokenizer.nextToken();
if (token != JsonToken.EOF) {
throw new JsonParsingException(JsonMessages.PARSER_EXPECTED_EOF(token),
getLastCharLocation());
}
return false;
}
return true;
}
@Override
public JsonParser.Event next() {
if (!hasNext()) {
throw new NoSuchElementException();
}
return currentEvent = currentContext.getNextEvent();
}
@Override
public void remove() {
throw new UnsupportedOperationException();
}
}
public void close() {
try {
tokenizer.close();
} catch (IOException e) {
throw new JsonException(JsonMessages.PARSER_TOKENIZER_CLOSE_IO(), e);
}
}
// Using the optimized stack impl as we don't require other things
// like iterator etc.
private static final class Stack {
private Context head;
private void push(Context context) {
context.next = head;
head = context;
}
private Context pop() {
if (head == null) {
throw new NoSuchElementException();
}
Context temp = head;
head = head.next;
return temp;
}
private boolean isEmpty() {
return head == null;
}
}
private abstract class Context {
Context next;
abstract Event getNextEvent();
}
private final class NoneContext extends Context {
@Override
public Event getNextEvent() {
// Handle 1. { 2. [
JsonToken token = tokenizer.nextToken();
if (token == JsonToken.CURLYOPEN) {
stack.push(currentContext);
currentContext = new ObjectContext();
return Event.START_OBJECT;
} else if (token == JsonToken.SQUAREOPEN) {
stack.push(currentContext);
currentContext = new ArrayContext();
return Event.START_ARRAY;
}
throw parsingException(token, "[CURLYOPEN, SQUAREOPEN]");
}
}
private JsonParsingException parsingException(JsonToken token, String expectedTokens) {
JsonLocation location = getLastCharLocation();
return new JsonParsingException(
JsonMessages.PARSER_INVALID_TOKEN(token, location, expectedTokens), location);
}
private final class ObjectContext extends Context {
private boolean firstValue = true;
/*
* Some more things could be optimized. For example, instead
* tokenizer.nextToken(), one could use tokenizer.matchColonToken() to
* match ':'. That might optimize a bit, but will fragment nextToken().
* I think the current one is more readable.
*
*/
@Override
public Event getNextEvent() {
// Handle 1. } 2. name:value 3. ,name:value
JsonToken token = tokenizer.nextToken();
if (currentEvent == Event.KEY_NAME) {
// Handle 1. :value
if (token != JsonToken.COLON) {
throw parsingException(token, "[COLON]");
}
token = tokenizer.nextToken();
if (token.isValue()) {
return token.getEvent();
} else if (token == JsonToken.CURLYOPEN) {
stack.push(currentContext);
currentContext = new ObjectContext();
return Event.START_OBJECT;
} else if (token == JsonToken.SQUAREOPEN) {
stack.push(currentContext);
currentContext = new ArrayContext();
return Event.START_ARRAY;
}
throw parsingException(token, "[CURLYOPEN, SQUAREOPEN, STRING, NUMBER, TRUE, FALSE, NULL]");
} else {
// Handle 1. } 2. name 3. ,name
if (token == JsonToken.CURLYCLOSE) {
currentContext = stack.pop();
return Event.END_OBJECT;
}
if (firstValue) {
firstValue = false;
} else {
if (token != JsonToken.COMMA) {
throw parsingException(token, "[COMMA]");
}
token = tokenizer.nextToken();
}
if (token == JsonToken.STRING) {
return Event.KEY_NAME;
}
throw parsingException(token, "[STRING]");
}
}
}
private final class ArrayContext extends Context {
private boolean firstValue = true;
// Handle 1. ] 2. value 3. ,value
@Override
public Event getNextEvent() {
JsonToken token = tokenizer.nextToken();
if (token == JsonToken.SQUARECLOSE) {
currentContext = stack.pop();
return Event.END_ARRAY;
}
if (firstValue) {
firstValue = false;
} else {
if (token != JsonToken.COMMA) {
throw parsingException(token, "[COMMA]");
}
token = tokenizer.nextToken();
}
if (token.isValue()) {
return token.getEvent();
} else if (token == JsonToken.CURLYOPEN) {
stack.push(currentContext);
currentContext = new ObjectContext();
return Event.START_OBJECT;
} else if (token == JsonToken.SQUAREOPEN) {
stack.push(currentContext);
currentContext = new ArrayContext();
return Event.START_ARRAY;
}
throw parsingException(token, "[CURLYOPEN, SQUAREOPEN, STRING, NUMBER, TRUE, FALSE, NULL]");
}
}
}