Pretty writer
Selebrator
7 years ago
parent
5c99b596dc
commit
c50b969882
@ -0,0 +1,11 @@
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package _8.io;
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public enum SonState {
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EMPTY_DOCUMENT,
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NONEMPTY_DOCUMENT,
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EMPTY_ARRAY,
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NONEMPTY_ARRAY,
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EMPTY_OBJECT,
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NONEMPTY_OBJECT,
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DANGLING_NAME
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}
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@ -0,0 +1,198 @@
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package _8.io;
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import java.io.Closeable;
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import java.io.Flushable;
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import java.io.IOException;
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import java.io.Writer;
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import java.util.Arrays;
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import static _8.io.SonState.*;
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public class SonWriter implements Closeable, Flushable {
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private static final String nextIndicator = ",";
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private final Writer out;
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private String indent;
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private String keyValueSeparator;
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private SonState[] stack = new SonState[32];
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private int stackTop = 0;
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private String nextName;
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public SonWriter(Writer out) {
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this.out = out;
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this.push(EMPTY_DOCUMENT);
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this.setIndent(" ");
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}
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public final void setIndent(String indent) {
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if(indent == null || indent.length() == 0) {
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this.indent = null;
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this.keyValueSeparator = ":";
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} else {
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this.indent = indent;
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this.keyValueSeparator = ": ";
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}
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}
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public SonWriter beginObject() throws IOException {
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this.open(EMPTY_OBJECT, "{");
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return this;
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}
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public SonWriter endObject() throws IOException {
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this.close(EMPTY_OBJECT, NONEMPTY_OBJECT, "}");
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return this;
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}
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public SonWriter beginArray() throws IOException {
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this.open(EMPTY_ARRAY, "[");
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return this;
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}
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public SonWriter endArray() throws IOException {
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this.close(EMPTY_ARRAY, NONEMPTY_ARRAY, "]");
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return this;
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}
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private void open(SonState empty, String openBracket) throws IOException {
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this.writeName();
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this.prepareValue();
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this.push(empty);
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this.out.write(openBracket);
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}
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private void close(SonState empty, SonState nonempty, String closedBracket) throws IOException {
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SonState state = this.peek();
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if(state != empty && state != nonempty) {
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throw new IllegalStateException("Can't close what's not open");
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}
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if(this.nextName != null) {
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throw new IllegalStateException("Dangling name: " + this.nextName);
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}
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this.pop();
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if(state == nonempty) {
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this.newline();
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}
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this.out.write(closedBracket);
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}
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public SonWriter name(String name) {
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if(name == null) {
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throw new NullPointerException("name == null");
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}
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if(this.nextName != null) {
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throw new IllegalStateException("Didn't expect a name again");
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}
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this.nextName = name;
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return this;
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}
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public SonWriter value(String value) throws IOException {
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this.writeName();
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this.prepareValue();
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this.out.write(value);
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return this;
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}
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public SonWriter value(Boolean value) throws IOException {
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return this.value(value ? "true" : "false");
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}
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public SonWriter value(Number value) throws IOException {
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return this.value(value.toString());
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}
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private void writeName() throws IOException {
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if(this.nextName != null) {
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this.prepareName();
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this.out.write(this.nextName);
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this.nextName = null;
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}
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}
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private void prepareName() throws IOException {
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SonState state = this.peek();
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if(state == NONEMPTY_OBJECT) { // not first in an object
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this.out.write(nextIndicator);
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} else if(state != EMPTY_OBJECT) { // not in an object
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throw new IllegalStateException("Didn't expect this to be named");
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}
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this.newline();
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this.replaceTop(DANGLING_NAME);
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}
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private void newline() throws IOException {
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if(this.indent == null) {
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return;
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}
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this.out.write("\n");
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for(int i = 1; i < this.stackTop; i++) {
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this.out.write(this.indent);
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}
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}
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private void prepareValue() throws IOException {
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SonState state = this.peek();
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switch(state) {
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case EMPTY_DOCUMENT:
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this.replaceTop(NONEMPTY_DOCUMENT);
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break;
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case EMPTY_ARRAY:
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this.replaceTop(NONEMPTY_ARRAY);
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this.newline();
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break;
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case NONEMPTY_ARRAY:
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this.out.write(nextIndicator);
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this.newline();
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break;
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case DANGLING_NAME:
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this.out.write(this.keyValueSeparator);
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this.replaceTop(NONEMPTY_OBJECT);
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break;
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default:
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throw new IllegalStateException();
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}
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}
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@Override
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public void flush() throws IOException {
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if(this.stackTop == 0) {
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throw new IllegalStateException("SonWriter already closed");
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}
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this.out.flush();
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}
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@Override
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public void close() throws IOException {
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this.out.close();
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if(this.stackTop > 1 || this.stackTop == 1 && this.peek() != NONEMPTY_DOCUMENT) {
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throw new IOException("Incomplete document");
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}
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this.stackTop = 0;
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}
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/* stack management */
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private SonState peek() {
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return this.stack[this.stackTop - 1];
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}
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private SonState pop() {
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return this.stack[--this.stackTop];
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}
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private void push(SonState newTop) {
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if(this.stackTop >= this.stack.length) {
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this.stack = Arrays.copyOf(this.stack, this.stackTop * 2);
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}
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this.stack[this.stackTop++] = newTop;
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}
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private void replaceTop(SonState newTop) {
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this.stack[this.stackTop - 1] = newTop;
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}
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}
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