/*******************************************************************************
* Copyright 2011 See AUTHORS file.
*
* Licensed 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.badlogic.gdx.utils;
import java.io.IOException;
import java.io.Writer;
import java.math.BigDecimal;
import java.math.BigInteger;
import java.util.regex.Pattern;
/** Builder style API for emitting JSON.
* @author Nathan Sweet */
public class JsonWriter extends Writer {
final Writer writer;
private final Array<JsonObject> stack = new Array();
private JsonObject current;
private boolean named;
private OutputType outputType = OutputType.json;
private boolean quoteLongValues = false;
public JsonWriter (Writer writer) {
this.writer = writer;
}
public Writer getWriter () {
return writer;
}
/** Sets the type of JSON output. Default is {@link OutputType#minimal}. */
public void setOutputType (OutputType outputType) {
this.outputType = outputType;
}
/** When true, quotes long, double, BigInteger, BigDecimal types to prevent truncation in languages like JavaScript and PHP.
* This is not necessary when using libgdx, which handles these types without truncation. Default is false. */
public void setQuoteLongValues (boolean quoteLongValues) {
this.quoteLongValues = quoteLongValues;
}
public JsonWriter name (String name) throws IOException {
if (current == null || current.array) throw new IllegalStateException("Current item must be an object.");
if (!current.needsComma)
current.needsComma = true;
else
writer.write(',');
writer.write(outputType.quoteName(name));
writer.write(':');
named = true;
return this;
}
public JsonWriter object () throws IOException {
requireCommaOrName();
stack.add(current = new JsonObject(false));
return this;
}
public JsonWriter array () throws IOException {
requireCommaOrName();
stack.add(current = new JsonObject(true));
return this;
}
public JsonWriter value (Object value) throws IOException {
if (quoteLongValues
&& (value instanceof Long || value instanceof Double || value instanceof BigDecimal || value instanceof BigInteger)) {
value = value.toString();
} else if (value instanceof Number) {
Number number = (Number)value;
long longValue = number.longValue();
if (number.doubleValue() == longValue) value = longValue;
}
requireCommaOrName();
writer.write(outputType.quoteValue(value));
return this;
}
/** Writes the specified JSON value, without quoting or escaping. */
public JsonWriter json (String json) throws IOException {
requireCommaOrName();
writer.write(json);
return this;
}
private void requireCommaOrName () throws IOException {
if (current == null) return;
if (current.array) {
if (!current.needsComma)
current.needsComma = true;
else
writer.write(',');
} else {
if (!named) throw new IllegalStateException("Name must be set.");
named = false;
}
}
public JsonWriter object (String name) throws IOException {
return name(name).object();
}
public JsonWriter array (String name) throws IOException {
return name(name).array();
}
public JsonWriter set (String name, Object value) throws IOException {
return name(name).value(value);
}
/** Writes the specified JSON value, without quoting or escaping. */
public JsonWriter json (String name, String json) throws IOException {
return name(name).json(json);
}
public JsonWriter pop () throws IOException {
if (named) throw new IllegalStateException("Expected an object, array, or value since a name was set.");
stack.pop().close();
current = stack.size == 0 ? null : stack.peek();
return this;
}
public void write (char[] cbuf, int off, int len) throws IOException {
writer.write(cbuf, off, len);
}
public void flush () throws IOException {
writer.flush();
}
public void close () throws IOException {
while (stack.size > 0)
pop();
writer.close();
}
private class JsonObject {
final boolean array;
boolean needsComma;
JsonObject (boolean array) throws IOException {
this.array = array;
writer.write(array ? '[' : '{');
}
void close () throws IOException {
writer.write(array ? ']' : '}');
}
}
static public enum OutputType {
/** Normal JSON, with all its double quotes. */
json,
/** Like JSON, but names are only double quoted if necessary. */
javascript,
/** Like JSON, but:
* <ul>
* <li>Names only require double quotes if they start with <code>space</code> or any of <code>":,}/</code> or they contain
* <code>//</code> or <code>/*</code> or <code>:</code>.
* <li>Values only require double quotes if they start with <code>space</code> or any of <code>":,{[]/</code> or they
* contain <code>//</code> or <code>/*</code> or any of <code>}],</code> or they are equal to <code>true</code>,
* <code>false</code> , or <code>null</code>.
* <li>Newlines are treated as commas, making commas optional in many cases.
* <li>C style comments may be used: <code>//...</code> or <code>/*...*<b></b>/</code>
* </ul> */
minimal;
static private Pattern javascriptPattern = Pattern.compile("^[a-zA-Z_$][a-zA-Z_$0-9]*$");
static private Pattern minimalNamePattern = Pattern.compile("^[^\":,}/ ][^:]*$");
static private Pattern minimalValuePattern = Pattern.compile("^[^\":,{\\[\\]/ ][^}\\],]*$");
public String quoteValue (Object value) {
if (value == null) return "null";
String string = value.toString();
if (value instanceof Number || value instanceof Boolean) return string;
StringBuilder buffer = new StringBuilder(string);
buffer.replace('\\', "\\\\").replace('\r', "\\r").replace('\n', "\\n").replace('\t', "\\t");
if (this == OutputType.minimal && !string.equals("true") && !string.equals("false") && !string.equals("null")
&& !string.contains("//") && !string.contains("/*")) {
int length = buffer.length();
if (length > 0 && buffer.charAt(length - 1) != ' ' && minimalValuePattern.matcher(buffer).matches())
return buffer.toString();
}
return '"' + buffer.replace('"', "\\\"").toString() + '"';
}
public String quoteName (String value) {
StringBuilder buffer = new StringBuilder(value);
buffer.replace('\\', "\\\\").replace('\r', "\\r").replace('\n', "\\n").replace('\t', "\\t");
switch (this) {
case minimal:
if (!value.contains("//") && !value.contains("/*") && minimalNamePattern.matcher(buffer).matches())
return buffer.toString();
case javascript:
if (javascriptPattern.matcher(buffer).matches()) return buffer.toString();
}
return '"' + buffer.replace('"', "\\\"").toString() + '"';
}
}
}