/*
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* Copyright (C) 2011 Google Inc.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package cn.emay.sdk.util.json.gson.internal.bind;
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import java.io.IOException;
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import java.io.Reader;
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import java.util.ArrayList;
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import java.util.Iterator;
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import java.util.List;
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import java.util.Map;
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import cn.emay.sdk.util.json.gson.JsonArray;
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import cn.emay.sdk.util.json.gson.JsonElement;
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import cn.emay.sdk.util.json.gson.JsonNull;
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import cn.emay.sdk.util.json.gson.JsonObject;
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import cn.emay.sdk.util.json.gson.JsonPrimitive;
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import cn.emay.sdk.util.json.gson.stream.JsonReader;
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import cn.emay.sdk.util.json.gson.stream.JsonToken;
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/**
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* This reader walks the elements of a JsonElement as if it was coming from a
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* character stream.
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*
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* @author Jesse Wilson
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*/
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public final class JsonTreeReader extends JsonReader {
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private static final Reader UNREADABLE_READER = new Reader() {
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@Override
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public int read(char[] buffer, int offset, int count) throws IOException {
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throw new AssertionError();
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}
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@Override
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public void close() throws IOException {
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throw new AssertionError();
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}
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};
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private static final Object SENTINEL_CLOSED = new Object();
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private final List<Object> stack = new ArrayList<Object>();
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public JsonTreeReader(JsonElement element) {
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super(UNREADABLE_READER);
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stack.add(element);
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}
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@Override
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public void beginArray() throws IOException {
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expect(JsonToken.BEGIN_ARRAY);
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JsonArray array = (JsonArray) peekStack();
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stack.add(array.iterator());
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}
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@Override
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public void endArray() throws IOException {
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expect(JsonToken.END_ARRAY);
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popStack(); // empty iterator
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popStack(); // array
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}
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@Override
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public void beginObject() throws IOException {
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expect(JsonToken.BEGIN_OBJECT);
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JsonObject object = (JsonObject) peekStack();
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stack.add(object.entrySet().iterator());
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}
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@Override
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public void endObject() throws IOException {
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expect(JsonToken.END_OBJECT);
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popStack(); // empty iterator
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popStack(); // object
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}
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@Override
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public boolean hasNext() throws IOException {
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JsonToken token = peek();
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return token != JsonToken.END_OBJECT && token != JsonToken.END_ARRAY;
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}
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@Override
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public JsonToken peek() throws IOException {
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if (stack.isEmpty()) {
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return JsonToken.END_DOCUMENT;
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}
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Object o = peekStack();
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if (o instanceof Iterator) {
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boolean isObject = stack.get(stack.size() - 2) instanceof JsonObject;
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Iterator<?> iterator = (Iterator<?>) o;
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if (iterator.hasNext()) {
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if (isObject) {
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return JsonToken.NAME;
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} else {
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stack.add(iterator.next());
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return peek();
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}
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} else {
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return isObject ? JsonToken.END_OBJECT : JsonToken.END_ARRAY;
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}
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} else if (o instanceof JsonObject) {
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return JsonToken.BEGIN_OBJECT;
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} else if (o instanceof JsonArray) {
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return JsonToken.BEGIN_ARRAY;
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} else if (o instanceof JsonPrimitive) {
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JsonPrimitive primitive = (JsonPrimitive) o;
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if (primitive.isString()) {
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return JsonToken.STRING;
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} else if (primitive.isBoolean()) {
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return JsonToken.BOOLEAN;
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} else if (primitive.isNumber()) {
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return JsonToken.NUMBER;
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} else {
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throw new AssertionError();
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}
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} else if (o instanceof JsonNull) {
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return JsonToken.NULL;
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} else if (o == SENTINEL_CLOSED) {
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throw new IllegalStateException("JsonReader is closed");
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} else {
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throw new AssertionError();
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}
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}
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private Object peekStack() {
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return stack.get(stack.size() - 1);
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}
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private Object popStack() {
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return stack.remove(stack.size() - 1);
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}
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private void expect(JsonToken expected) throws IOException {
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if (peek() != expected) {
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throw new IllegalStateException("Expected " + expected + " but was " + peek());
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}
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}
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@Override
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public String nextName() throws IOException {
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expect(JsonToken.NAME);
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Iterator<?> i = (Iterator<?>) peekStack();
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Map.Entry<?, ?> entry = (Map.Entry<?, ?>) i.next();
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stack.add(entry.getValue());
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return (String) entry.getKey();
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}
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@Override
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public String nextString() throws IOException {
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JsonToken token = peek();
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if (token != JsonToken.STRING && token != JsonToken.NUMBER) {
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throw new IllegalStateException("Expected " + JsonToken.STRING + " but was " + token);
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}
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return ((JsonPrimitive) popStack()).getAsString();
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}
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@Override
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public boolean nextBoolean() throws IOException {
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expect(JsonToken.BOOLEAN);
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return ((JsonPrimitive) popStack()).getAsBoolean();
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}
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@Override
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public void nextNull() throws IOException {
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expect(JsonToken.NULL);
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popStack();
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}
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@Override
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public double nextDouble() throws IOException {
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JsonToken token = peek();
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if (token != JsonToken.NUMBER && token != JsonToken.STRING) {
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throw new IllegalStateException("Expected " + JsonToken.NUMBER + " but was " + token);
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}
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double result = ((JsonPrimitive) peekStack()).getAsDouble();
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if (!isLenient() && (Double.isNaN(result) || Double.isInfinite(result))) {
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throw new NumberFormatException("JSON forbids NaN and infinities: " + result);
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}
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popStack();
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return result;
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}
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@Override
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public long nextLong() throws IOException {
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JsonToken token = peek();
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if (token != JsonToken.NUMBER && token != JsonToken.STRING) {
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throw new IllegalStateException("Expected " + JsonToken.NUMBER + " but was " + token);
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}
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long result = ((JsonPrimitive) peekStack()).getAsLong();
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popStack();
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return result;
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}
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@Override
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public int nextInt() throws IOException {
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JsonToken token = peek();
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if (token != JsonToken.NUMBER && token != JsonToken.STRING) {
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throw new IllegalStateException("Expected " + JsonToken.NUMBER + " but was " + token);
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}
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int result = ((JsonPrimitive) peekStack()).getAsInt();
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popStack();
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return result;
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}
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@Override
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public void close() throws IOException {
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stack.clear();
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stack.add(SENTINEL_CLOSED);
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}
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@Override
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public void skipValue() throws IOException {
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if (peek() == JsonToken.NAME) {
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nextName();
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} else {
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popStack();
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}
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}
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@Override
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public String toString() {
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return getClass().getSimpleName();
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}
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public void promoteNameToValue() throws IOException {
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expect(JsonToken.NAME);
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Iterator<?> i = (Iterator<?>) peekStack();
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Map.Entry<?, ?> entry = (Map.Entry<?, ?>) i.next();
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stack.add(entry.getValue());
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stack.add(new JsonPrimitive((String) entry.getKey()));
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}
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}
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