com.ajjpj.abase.io.AJsonSerHelper Maven / Gradle / Ivy
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package com.ajjpj.abase.io;
import com.ajjpj.abase.collection.mutable.ArrayStack;
import java.io.IOException;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.Writer;
import java.nio.charset.Charset;
import java.text.DecimalFormat;
import java.text.DecimalFormatSymbols;
import java.util.Locale;
/**
* This class is a collection of helper methods for manually writing JSON to an OutputStream.
*
* For details on the JSON spec, see http://json.org
*
* @author arno
*/
public class AJsonSerHelper {
static final Charset UTF_8 = Charset.forName("UTF-8");
private static final int[] TEN_POW = new int[] {1, 10, 100, 1000, 10*1000, 100*1000, 1000*1000, 10*1000*1000, 100*1000*1000, 1000*1000*1000};
private static final String[] PATTERNS = new String[] {"0", "0.0", "0.00", "0.000", "0.0000", "0.00000", "0.000000", "0.0000000", "0.00000000", "0.000000000"};
private static final DecimalFormatSymbols DECIMAL_FORMAT_SYMBOLS = new DecimalFormatSymbols(Locale.US);
private final Writer out;
private final ArrayStack state = new ArrayStack<
>();
public AJsonSerHelper(OutputStream out) {
this.out = new OutputStreamWriter(out, UTF_8);
state.push(JsonSerState.initial);
}
public void startObject() throws IOException {
checkAcceptsValueAndPrefixComma();
state.push(JsonSerState.startOfObject);
out.write("{");
}
public void endObject() throws IOException {
checkInObject();
state.pop();
out.write("}");
afterValueWritten();
}
public void writeKey(String key) throws IOException {
if(!state().acceptsKey) {
throw new IllegalStateException("state " + state() + " does not accept a key");
}
if(state() == JsonSerState.inObject) {
out.write(",");
}
_writeStringLiteral(key);
out.write(":");
state.push(JsonSerState.afterKey);
}
public void startArray() throws IOException {
checkAcceptsValueAndPrefixComma();
state.push(JsonSerState.startOfArray);
out.write("[");
}
public void endArray() throws IOException {
checkInArray();
state.pop();
out.write("]");
afterValueWritten();
}
public void writeStringLiteral(String s) throws IOException {
checkAcceptsValueAndPrefixComma();
if(s == null) {
writeNullLiteral();
}
else {
_writeStringLiteral(s);
}
afterValueWritten();
}
private void _writeStringLiteral(String s) throws IOException {
out.write('"');
for(int i=0; i