JsonOutput.java
/*
* Copyright 2001-present Stephen Colebourne
*
* 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 org.joda.beans.ser.json;
import java.io.IOException;
import java.util.BitSet;
/**
* Outputter for JSON data.
*/
final class JsonOutput {
/** encoding JSON */
private static final String[] REPLACE = new String[128];
static {
for (int i = 0; i < 32; i++) {
REPLACE[i] = String.format("\\u%04x", i);
}
REPLACE['\b'] = "\\b";
REPLACE['\t'] = "\\t";
REPLACE['\n'] = "\\n";
REPLACE['\f'] = "\\f";
REPLACE['\r'] = "\\r";
REPLACE['"'] = "\\\"";
REPLACE['\\'] = "\\\\";
REPLACE[127] = "\\u007f";
}
/**
* The appender to write to.
*/
private final Appendable output;
/**
* The indent amount.
*/
private final String indent;
/**
* The new line.
*/
private final String newLine;
/**
* The current indent.
*/
private String currentIndent = "";
/**
* The comma depth.
*/
private int commaDepth;
/**
* The comma state.
*/
private BitSet commaState = new BitSet(64);
/**
* Creates an instance that outputs in compact format.
*
* @param output the output to write to, not null
*/
JsonOutput(Appendable output) {
this(output, "", "");
}
/**
* Creates an instance where the output format can be controlled.
*
* @param output the output to write to, not null
* @param indent the pretty format indent
* @param newLine the pretty format new line
*/
JsonOutput(Appendable output, String indent, String newLine) {
this.output = output;
this.indent = indent;
this.newLine = newLine;
}
//-----------------------------------------------------------------------
/**
* Writes a JSON null.
*
* @throws IOException if an error occurs
*/
void writeNull() throws IOException {
output.append("null");
}
/**
* Writes a JSON boolean.
*
* @param value the value
* @throws IOException if an error occurs
*/
void writeBoolean(boolean value) throws IOException {
if (value) {
output.append("true");
} else {
output.append("false");
}
}
//-----------------------------------------------------------------------
/**
* Writes a JSON int.
*
* @param value the value
* @throws IOException if an error occurs
*/
void writeInt(int value) throws IOException {
if ((value & 0xfffffff8) == 0) {
output.append((char) (value + 48));
} else {
output.append(Integer.toString(value));
}
}
/**
* Writes a JSON long.
*
* @param value the value
* @throws IOException if an error occurs
*/
void writeLong(long value) throws IOException {
output.append(Long.toString(value));
}
/**
* Writes a JSON float.
* <p>
* This outputs the values of NaN, and Infinity as strings.
*
* @param value the value
* @throws IOException if an error occurs
*/
void writeFloat(float value) throws IOException {
if (Float.isNaN(value) || Float.isInfinite(value)) {
output.append('"').append(Float.toString(value)).append('"');
} else {
output.append(Float.toString(value));
}
}
/**
* Writes a JSON double.
* <p>
* This outputs the values of NaN, and Infinity as strings.
*
* @param value the value
* @throws IOException if an error occurs
*/
void writeDouble(double value) throws IOException {
if (Double.isNaN(value) || Double.isInfinite(value)) {
output.append('"').append(Double.toString(value)).append('"');
} else {
output.append(Double.toString(value));
}
}
//-----------------------------------------------------------------------
/**
* Writes a JSON string.
*
* @param value the value
* @throws IOException if an error occurs
*/
void writeString(String value) throws IOException {
output.append('"');
for (int i = 0; i < value.length(); i++) {
char ch = value.charAt(i);
if (ch < 128) {
String replace = REPLACE[ch];
if (replace != null) {
output.append(replace);
} else {
output.append(ch);
}
} else if (ch == '\u2028') {
output.append("\\u2028"); // match other JSON writers
} else if (ch == '\u2029') {
output.append("\\u2029"); // match other JSON writers
} else {
output.append(ch);
}
}
output.append('"');
}
//-----------------------------------------------------------------------
/**
* Writes a JSON array start.
*
* @throws IOException if an error occurs
*/
void writeArrayStart() throws IOException {
output.append('[');
commaDepth++;
commaState.clear(commaDepth);
}
/**
* Writes a JSON array item start.
*
* @throws IOException if an error occurs
*/
void writeArrayItemStart() throws IOException {
if (commaState.get(commaDepth)) {
output.append(',');
if (newLine.length() > 0) {
output.append(' ');
}
} else {
commaState.set(commaDepth);
}
}
/**
* Writes a JSON array end.
*
* @throws IOException if an error occurs
*/
void writeArrayEnd() throws IOException {
output.append(']');
commaDepth--;
}
//-----------------------------------------------------------------------
/**
* Writes a JSON object start.
*
* @throws IOException if an error occurs
*/
void writeObjectStart() throws IOException {
output.append('{');
currentIndent = currentIndent + indent;
commaDepth++;
commaState.set(commaDepth, false);
}
/**
* Writes a JSON object key.
* <p>
* This handles the comma, string encoded key and separator colon.
*
* @param key the item key
* @throws IOException if an error occurs
*/
void writeObjectKey(String key) throws IOException {
if (commaState.get(commaDepth)) {
output.append(',');
} else {
commaState.set(commaDepth, true);
}
output.append(newLine);
output.append(currentIndent);
writeString(key);
output.append(':');
if (newLine.length() > 0) {
output.append(' ');
}
}
/**
* Writes a JSON object key and value.
*
* @param key the item key
* @param value the item value
* @throws IOException if an error occurs
*/
void writeObjectKeyValue(String key, String value) throws IOException {
writeObjectKey(key);
writeString(value);
}
/**
* Writes a JSON object end.
*
* @throws IOException if an error occurs
*/
void writeObjectEnd() throws IOException {
currentIndent = currentIndent.substring(0, currentIndent.length() - indent.length());
if (commaState.get(commaDepth)) {
output.append(newLine);
output.append(currentIndent);
}
output.append('}');
commaDepth--;
}
}