+++ /dev/null
-/*
- * Copyright (C) 2010 Google Inc.
- *
- * 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.google.gson.stream;
-
-import java.io.Closeable;
-import java.io.Flushable;
-import java.io.IOException;
-import java.io.Writer;
-
-import static com.google.gson.stream.JsonScope.DANGLING_NAME;
-import static com.google.gson.stream.JsonScope.EMPTY_ARRAY;
-import static com.google.gson.stream.JsonScope.EMPTY_DOCUMENT;
-import static com.google.gson.stream.JsonScope.EMPTY_OBJECT;
-import static com.google.gson.stream.JsonScope.NONEMPTY_ARRAY;
-import static com.google.gson.stream.JsonScope.NONEMPTY_DOCUMENT;
-import static com.google.gson.stream.JsonScope.NONEMPTY_OBJECT;
-
-/**
- * Writes a JSON (<a href="http://www.ietf.org/rfc/rfc4627.txt">RFC 4627</a>)
- * encoded value to a stream, one token at a time. The stream includes both
- * literal values (strings, numbers, booleans and nulls) as well as the begin
- * and end delimiters of objects and arrays.
- *
- * <h3>Encoding JSON</h3>
- * To encode your data as JSON, create a new {@code JsonWriter}. Each JSON
- * document must contain one top-level array or object. Call methods on the
- * writer as you walk the structure's contents, nesting arrays and objects as
- * necessary:
- * <ul>
- * <li>To write <strong>arrays</strong>, first call {@link #beginArray()}.
- * Write each of the array's elements with the appropriate {@link #value}
- * methods or by nesting other arrays and objects. Finally close the array
- * using {@link #endArray()}.
- * <li>To write <strong>objects</strong>, first call {@link #beginObject()}.
- * Write each of the object's properties by alternating calls to
- * {@link #name} with the property's value. Write property values with the
- * appropriate {@link #value} method or by nesting other objects or arrays.
- * Finally close the object using {@link #endObject()}.
- * </ul>
- *
- * <h3>Example</h3>
- * Suppose we'd like to encode a stream of messages such as the following: <pre> {@code
- * [
- * {
- * "id": 912345678901,
- * "text": "How do I stream JSON in Java?",
- * "geo": null,
- * "user": {
- * "name": "json_newb",
- * "followers_count": 41
- * }
- * },
- * {
- * "id": 912345678902,
- * "text": "@json_newb just use JsonWriter!",
- * "geo": [50.454722, -104.606667],
- * "user": {
- * "name": "jesse",
- * "followers_count": 2
- * }
- * }
- * ]}</pre>
- * This code encodes the above structure: <pre> {@code
- * public void writeJsonStream(OutputStream out, List<Message> messages) throws IOException {
- * JsonWriter writer = new JsonWriter(new OutputStreamWriter(out, "UTF-8"));
- * writer.setIndentSpaces(4);
- * writeMessagesArray(writer, messages);
- * writer.close();
- * }
- *
- * public void writeMessagesArray(JsonWriter writer, List<Message> messages) throws IOException {
- * writer.beginArray();
- * for (Message message : messages) {
- * writeMessage(writer, message);
- * }
- * writer.endArray();
- * }
- *
- * public void writeMessage(JsonWriter writer, Message message) throws IOException {
- * writer.beginObject();
- * writer.name("id").value(message.getId());
- * writer.name("text").value(message.getText());
- * if (message.getGeo() != null) {
- * writer.name("geo");
- * writeDoublesArray(writer, message.getGeo());
- * } else {
- * writer.name("geo").nullValue();
- * }
- * writer.name("user");
- * writeUser(writer, message.getUser());
- * writer.endObject();
- * }
- *
- * public void writeUser(JsonWriter writer, User user) throws IOException {
- * writer.beginObject();
- * writer.name("name").value(user.getName());
- * writer.name("followers_count").value(user.getFollowersCount());
- * writer.endObject();
- * }
- *
- * public void writeDoublesArray(JsonWriter writer, List<Double> doubles) throws IOException {
- * writer.beginArray();
- * for (Double value : doubles) {
- * writer.value(value);
- * }
- * writer.endArray();
- * }}</pre>
- *
- * <p>Each {@code JsonWriter} may be used to write a single JSON stream.
- * Instances of this class are not thread safe. Calls that would result in a
- * malformed JSON string will fail with an {@link IllegalStateException}.
- *
- * @author Jesse Wilson
- * @since 1.6
- */
-public class JsonWriter implements Closeable, Flushable {
-
- /*
- * From RFC 4627, "All Unicode characters may be placed within the
- * quotation marks except for the characters that must be escaped:
- * quotation mark, reverse solidus, and the control characters
- * (U+0000 through U+001F)."
- *
- * We also escape '\u2028' and '\u2029', which JavaScript interprets as
- * newline characters. This prevents eval() from failing with a syntax
- * error. http://code.google.com/p/google-gson/issues/detail?id=341
- */
- private static final String[] REPLACEMENT_CHARS;
- private static final String[] HTML_SAFE_REPLACEMENT_CHARS;
- static {
- REPLACEMENT_CHARS = new String[128];
- for (int i = 0; i <= 0x1f; i++) {
- REPLACEMENT_CHARS[i] = String.format("\\u%04x", (int) i);
- }
- REPLACEMENT_CHARS['"'] = "\\\"";
- REPLACEMENT_CHARS['\\'] = "\\\\";
- REPLACEMENT_CHARS['\t'] = "\\t";
- REPLACEMENT_CHARS['\b'] = "\\b";
- REPLACEMENT_CHARS['\n'] = "\\n";
- REPLACEMENT_CHARS['\r'] = "\\r";
- REPLACEMENT_CHARS['\f'] = "\\f";
- HTML_SAFE_REPLACEMENT_CHARS = REPLACEMENT_CHARS.clone();
- HTML_SAFE_REPLACEMENT_CHARS['<'] = "\\u003c";
- HTML_SAFE_REPLACEMENT_CHARS['>'] = "\\u003e";
- HTML_SAFE_REPLACEMENT_CHARS['&'] = "\\u0026";
- HTML_SAFE_REPLACEMENT_CHARS['='] = "\\u003d";
- HTML_SAFE_REPLACEMENT_CHARS['\''] = "\\u0027";
- }
-
- /** The output data, containing at most one top-level array or object. */
- private final Writer out;
-
- private int[] stack = new int[32];
- private int stackSize = 0;
- {
- push(EMPTY_DOCUMENT);
- }
-
- /**
- * A string containing a full set of spaces for a single level of
- * indentation, or null for no pretty printing.
- */
- private String indent;
-
- /**
- * The name/value separator; either ":" or ": ".
- */
- private String separator = ":";
-
- private boolean lenient;
-
- private boolean htmlSafe;
-
- private String deferredName;
-
- private boolean serializeNulls = true;
-
- /**
- * Creates a new instance that writes a JSON-encoded stream to {@code out}.
- * For best performance, ensure {@link Writer} is buffered; wrapping in
- * {@link java.io.BufferedWriter BufferedWriter} if necessary.
- */
- public JsonWriter(Writer out) {
- if (out == null) {
- throw new NullPointerException("out == null");
- }
- this.out = out;
- }
-
- /**
- * Sets the indentation string to be repeated for each level of indentation
- * in the encoded document. If {@code indent.isEmpty()} the encoded document
- * will be compact. Otherwise the encoded document will be more
- * human-readable.
- *
- * @param indent a string containing only whitespace.
- */
- public final void setIndent(String indent) {
- if (indent.length() == 0) {
- this.indent = null;
- this.separator = ":";
- } else {
- this.indent = indent;
- this.separator = ": ";
- }
- }
-
- /**
- * Configure this writer to relax its syntax rules. By default, this writer
- * only emits well-formed JSON as specified by <a
- * href="http://www.ietf.org/rfc/rfc4627.txt">RFC 4627</a>. Setting the writer
- * to lenient permits the following:
- * <ul>
- * <li>Top-level values of any type. With strict writing, the top-level
- * value must be an object or an array.
- * <li>Numbers may be {@link Double#isNaN() NaNs} or {@link
- * Double#isInfinite() infinities}.
- * </ul>
- */
- public final void setLenient(boolean lenient) {
- this.lenient = lenient;
- }
-
- /**
- * Returns true if this writer has relaxed syntax rules.
- */
- public boolean isLenient() {
- return lenient;
- }
-
- /**
- * Configure this writer to emit JSON that's safe for direct inclusion in HTML
- * and XML documents. This escapes the HTML characters {@code <}, {@code >},
- * {@code &} and {@code =} before writing them to the stream. Without this
- * setting, your XML/HTML encoder should replace these characters with the
- * corresponding escape sequences.
- */
- public final void setHtmlSafe(boolean htmlSafe) {
- this.htmlSafe = htmlSafe;
- }
-
- /**
- * Returns true if this writer writes JSON that's safe for inclusion in HTML
- * and XML documents.
- */
- public final boolean isHtmlSafe() {
- return htmlSafe;
- }
-
- /**
- * Sets whether object members are serialized when their value is null.
- * This has no impact on array elements. The default is true.
- */
- public final void setSerializeNulls(boolean serializeNulls) {
- this.serializeNulls = serializeNulls;
- }
-
- /**
- * Returns true if object members are serialized when their value is null.
- * This has no impact on array elements. The default is true.
- */
- public final boolean getSerializeNulls() {
- return serializeNulls;
- }
-
- /**
- * Begins encoding a new array. Each call to this method must be paired with
- * a call to {@link #endArray}.
- *
- * @return this writer.
- */
- public JsonWriter beginArray() throws IOException {
- writeDeferredName();
- return open(EMPTY_ARRAY, "[");
- }
-
- /**
- * Ends encoding the current array.
- *
- * @return this writer.
- */
- public JsonWriter endArray() throws IOException {
- return close(EMPTY_ARRAY, NONEMPTY_ARRAY, "]");
- }
-
- /**
- * Begins encoding a new object. Each call to this method must be paired
- * with a call to {@link #endObject}.
- *
- * @return this writer.
- */
- public JsonWriter beginObject() throws IOException {
- writeDeferredName();
- return open(EMPTY_OBJECT, "{");
- }
-
- /**
- * Ends encoding the current object.
- *
- * @return this writer.
- */
- public JsonWriter endObject() throws IOException {
- return close(EMPTY_OBJECT, NONEMPTY_OBJECT, "}");
- }
-
- /**
- * Enters a new scope by appending any necessary whitespace and the given
- * bracket.
- */
- private JsonWriter open(int empty, String openBracket) throws IOException {
- beforeValue(true);
- push(empty);
- out.write(openBracket);
- return this;
- }
-
- /**
- * Closes the current scope by appending any necessary whitespace and the
- * given bracket.
- */
- private JsonWriter close(int empty, int nonempty, String closeBracket)
- throws IOException {
- int context = peek();
- if (context != nonempty && context != empty) {
- throw new IllegalStateException("Nesting problem.");
- }
- if (deferredName != null) {
- throw new IllegalStateException("Dangling name: " + deferredName);
- }
-
- stackSize--;
- if (context == nonempty) {
- newline();
- }
- out.write(closeBracket);
- return this;
- }
-
- private void push(int newTop) {
- if (stackSize == stack.length) {
- int[] newStack = new int[stackSize * 2];
- System.arraycopy(stack, 0, newStack, 0, stackSize);
- stack = newStack;
- }
- stack[stackSize++] = newTop;
- }
-
- /**
- * Returns the value on the top of the stack.
- */
- private int peek() {
- if (stackSize == 0) {
- throw new IllegalStateException("JsonWriter is closed.");
- }
- return stack[stackSize - 1];
- }
-
- /**
- * Replace the value on the top of the stack with the given value.
- */
- private void replaceTop(int topOfStack) {
- stack[stackSize - 1] = topOfStack;
- }
-
- /**
- * Encodes the property name.
- *
- * @param name the name of the forthcoming value. May not be null.
- * @return this writer.
- */
- public JsonWriter name(String name) throws IOException {
- if (name == null) {
- throw new NullPointerException("name == null");
- }
- if (deferredName != null) {
- throw new IllegalStateException();
- }
- if (stackSize == 0) {
- throw new IllegalStateException("JsonWriter is closed.");
- }
- deferredName = name;
- return this;
- }
-
- private void writeDeferredName() throws IOException {
- if (deferredName != null) {
- beforeName();
- string(deferredName);
- deferredName = null;
- }
- }
-
- /**
- * Encodes {@code value}.
- *
- * @param value the literal string value, or null to encode a null literal.
- * @return this writer.
- */
- public JsonWriter value(String value) throws IOException {
- if (value == null) {
- return nullValue();
- }
- writeDeferredName();
- beforeValue(false);
- string(value);
- return this;
- }
-
- /**
- * Encodes {@code null}.
- *
- * @return this writer.
- */
- public JsonWriter nullValue() throws IOException {
- if (deferredName != null) {
- if (serializeNulls) {
- writeDeferredName();
- } else {
- deferredName = null;
- return this; // skip the name and the value
- }
- }
- beforeValue(false);
- out.write("null");
- return this;
- }
-
- /**
- * Encodes {@code value}.
- *
- * @return this writer.
- */
- public JsonWriter value(boolean value) throws IOException {
- writeDeferredName();
- beforeValue(false);
- out.write(value ? "true" : "false");
- return this;
- }
-
- /**
- * Encodes {@code value}.
- *
- * @param value a finite value. May not be {@link Double#isNaN() NaNs} or
- * {@link Double#isInfinite() infinities}.
- * @return this writer.
- */
- public JsonWriter value(double value) throws IOException {
- if (Double.isNaN(value) || Double.isInfinite(value)) {
- throw new IllegalArgumentException("Numeric values must be finite, but was " + value);
- }
- writeDeferredName();
- beforeValue(false);
- out.append(Double.toString(value));
- return this;
- }
-
- /**
- * Encodes {@code value}.
- *
- * @return this writer.
- */
- public JsonWriter value(long value) throws IOException {
- writeDeferredName();
- beforeValue(false);
- out.write(Long.toString(value));
- return this;
- }
-
- /**
- * Encodes {@code value}.
- *
- * @param value a finite value. May not be {@link Double#isNaN() NaNs} or
- * {@link Double#isInfinite() infinities}.
- * @return this writer.
- */
- public JsonWriter value(Number value) throws IOException {
- if (value == null) {
- return nullValue();
- }
-
- writeDeferredName();
- String string = value.toString();
- if (!lenient
- && (string.equals("-Infinity") || string.equals("Infinity") || string.equals("NaN"))) {
- throw new IllegalArgumentException("Numeric values must be finite, but was " + value);
- }
- beforeValue(false);
- out.append(string);
- return this;
- }
-
- /**
- * Ensures all buffered data is written to the underlying {@link Writer}
- * and flushes that writer.
- */
- public void flush() throws IOException {
- if (stackSize == 0) {
- throw new IllegalStateException("JsonWriter is closed.");
- }
- out.flush();
- }
-
- /**
- * Flushes and closes this writer and the underlying {@link Writer}.
- *
- * @throws IOException if the JSON document is incomplete.
- */
- public void close() throws IOException {
- out.close();
-
- int size = stackSize;
- if (size > 1 || size == 1 && stack[size - 1] != NONEMPTY_DOCUMENT) {
- throw new IOException("Incomplete document");
- }
- stackSize = 0;
- }
-
- private void string(String value) throws IOException {
- String[] replacements = htmlSafe ? HTML_SAFE_REPLACEMENT_CHARS : REPLACEMENT_CHARS;
- out.write("\"");
- int last = 0;
- int length = value.length();
- for (int i = 0; i < length; i++) {
- char c = value.charAt(i);
- String replacement;
- if (c < 128) {
- replacement = replacements[c];
- if (replacement == null) {
- continue;
- }
- } else if (c == '\u2028') {
- replacement = "\\u2028";
- } else if (c == '\u2029') {
- replacement = "\\u2029";
- } else {
- continue;
- }
- if (last < i) {
- out.write(value, last, i - last);
- }
- out.write(replacement);
- last = i + 1;
- }
- if (last < length) {
- out.write(value, last, length - last);
- }
- out.write("\"");
- }
-
- private void newline() throws IOException {
- if (indent == null) {
- return;
- }
-
- out.write("\n");
- for (int i = 1, size = stackSize; i < size; i++) {
- out.write(indent);
- }
- }
-
- /**
- * Inserts any necessary separators and whitespace before a name. Also
- * adjusts the stack to expect the name's value.
- */
- private void beforeName() throws IOException {
- int context = peek();
- if (context == NONEMPTY_OBJECT) { // first in object
- out.write(',');
- } else if (context != EMPTY_OBJECT) { // not in an object!
- throw new IllegalStateException("Nesting problem.");
- }
- newline();
- replaceTop(DANGLING_NAME);
- }
-
- /**
- * Inserts any necessary separators and whitespace before a literal value,
- * inline array, or inline object. Also adjusts the stack to expect either a
- * closing bracket or another element.
- *
- * @param root true if the value is a new array or object, the two values
- * permitted as top-level elements.
- */
- @SuppressWarnings("fallthrough")
- private void beforeValue(boolean root) throws IOException {
- switch (peek()) {
- case NONEMPTY_DOCUMENT:
- if (!lenient) {
- throw new IllegalStateException(
- "JSON must have only one top-level value.");
- }
- // fall-through
- case EMPTY_DOCUMENT: // first in document
- if (!lenient && !root) {
- throw new IllegalStateException(
- "JSON must start with an array or an object.");
- }
- replaceTop(NONEMPTY_DOCUMENT);
- break;
-
- case EMPTY_ARRAY: // first in array
- replaceTop(NONEMPTY_ARRAY);
- newline();
- break;
-
- case NONEMPTY_ARRAY: // another in array
- out.append(',');
- newline();
- break;
-
- case DANGLING_NAME: // value for name
- out.append(separator);
- replaceTop(NONEMPTY_OBJECT);
- break;
-
- default:
- throw new IllegalStateException("Nesting problem.");
- }
- }
-}
projects / unical.git / blobdiff