/*
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* Copyright (C) 2008 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;
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import java.io.IOException;
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import java.io.StringWriter;
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import java.math.BigDecimal;
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import java.math.BigInteger;
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import cn.emay.sdk.util.json.gson.internal.Streams;
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import cn.emay.sdk.util.json.gson.stream.JsonWriter;
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/**
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* A class representing an element of Json. It could either be a
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* {@link JsonObject}, a {@link JsonArray}, a {@link JsonPrimitive} or a
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* {@link JsonNull}.
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*
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* @author Inderjeet Singh
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* @author Joel Leitch
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*/
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public abstract class JsonElement {
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/**
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* Returns a deep copy of this element. Immutable elements like primitives and
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* nulls are not copied.
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*/
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abstract JsonElement deepCopy();
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/**
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* provides check for verifying if this element is an array or not.
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*
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* @return true if this element is of type {@link JsonArray}, false otherwise.
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*/
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public boolean isJsonArray() {
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return this instanceof JsonArray;
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}
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/**
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* provides check for verifying if this element is a Json object or not.
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*
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* @return true if this element is of type {@link JsonObject}, false otherwise.
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*/
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public boolean isJsonObject() {
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return this instanceof JsonObject;
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}
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/**
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* provides check for verifying if this element is a primitive or not.
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*
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* @return true if this element is of type {@link JsonPrimitive}, false
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* otherwise.
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*/
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public boolean isJsonPrimitive() {
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return this instanceof JsonPrimitive;
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}
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/**
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* provides check for verifying if this element represents a null value or not.
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*
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* @return true if this element is of type {@link JsonNull}, false otherwise.
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* @since 1.2
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*/
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public boolean isJsonNull() {
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return this instanceof JsonNull;
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}
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/**
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* convenience method to get this element as a {@link JsonObject}. If the
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* element is of some other type, a {@link IllegalStateException} will result.
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* Hence it is best to use this method after ensuring that this element is of
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* the desired type by calling {@link #isJsonObject()} first.
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*
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* @return get this element as a {@link JsonObject}.
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* @throws IllegalStateException
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* if the element is of another type.
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*/
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public JsonObject getAsJsonObject() {
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if (isJsonObject()) {
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return (JsonObject) this;
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}
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throw new IllegalStateException("Not a JSON Object: " + this);
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}
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/**
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* convenience method to get this element as a {@link JsonArray}. If the element
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* is of some other type, a {@link IllegalStateException} will result. Hence it
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* is best to use this method after ensuring that this element is of the desired
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* type by calling {@link #isJsonArray()} first.
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*
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* @return get this element as a {@link JsonArray}.
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* @throws IllegalStateException
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* if the element is of another type.
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*/
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public JsonArray getAsJsonArray() {
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if (isJsonArray()) {
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return (JsonArray) this;
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}
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throw new IllegalStateException("This is not a JSON Array.");
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}
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/**
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* convenience method to get this element as a {@link JsonPrimitive}. If the
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* element is of some other type, a {@link IllegalStateException} will result.
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* Hence it is best to use this method after ensuring that this element is of
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* the desired type by calling {@link #isJsonPrimitive()} first.
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*
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* @return get this element as a {@link JsonPrimitive}.
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* @throws IllegalStateException
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* if the element is of another type.
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*/
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public JsonPrimitive getAsJsonPrimitive() {
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if (isJsonPrimitive()) {
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return (JsonPrimitive) this;
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}
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throw new IllegalStateException("This is not a JSON Primitive.");
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}
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/**
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* convenience method to get this element as a {@link JsonNull}. If the element
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* is of some other type, a {@link IllegalStateException} will result. Hence it
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* is best to use this method after ensuring that this element is of the desired
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* type by calling {@link #isJsonNull()} first.
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*
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* @return get this element as a {@link JsonNull}.
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* @throws IllegalStateException
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* if the element is of another type.
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* @since 1.2
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*/
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public JsonNull getAsJsonNull() {
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if (isJsonNull()) {
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return (JsonNull) this;
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}
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throw new IllegalStateException("This is not a JSON Null.");
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}
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/**
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* convenience method to get this element as a boolean value.
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*
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* @return get this element as a primitive boolean value.
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* @throws ClassCastException
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* if the element is of not a {@link JsonPrimitive} and is not a
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* valid boolean value.
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* @throws IllegalStateException
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* if the element is of the type {@link JsonArray} but contains more
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* than a single element.
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*/
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public boolean getAsBoolean() {
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throw new UnsupportedOperationException(getClass().getSimpleName());
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}
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/**
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* convenience method to get this element as a {@link Boolean} value.
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*
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* @return get this element as a {@link Boolean} value.
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* @throws ClassCastException
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* if the element is of not a {@link JsonPrimitive} and is not a
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* valid boolean value.
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* @throws IllegalStateException
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* if the element is of the type {@link JsonArray} but contains more
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* than a single element.
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*/
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Boolean getAsBooleanWrapper() {
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throw new UnsupportedOperationException(getClass().getSimpleName());
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}
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/**
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* convenience method to get this element as a {@link Number}.
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*
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* @return get this element as a {@link Number}.
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* @throws ClassCastException
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* if the element is of not a {@link JsonPrimitive} and is not a
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* valid number.
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* @throws IllegalStateException
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* if the element is of the type {@link JsonArray} but contains more
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* than a single element.
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*/
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public Number getAsNumber() {
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throw new UnsupportedOperationException(getClass().getSimpleName());
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}
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/**
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* convenience method to get this element as a string value.
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*
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* @return get this element as a string value.
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* @throws ClassCastException
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* if the element is of not a {@link JsonPrimitive} and is not a
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* valid string value.
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* @throws IllegalStateException
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* if the element is of the type {@link JsonArray} but contains more
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* than a single element.
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*/
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public String getAsString() {
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throw new UnsupportedOperationException(getClass().getSimpleName());
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}
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/**
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* convenience method to get this element as a primitive double value.
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*
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* @return get this element as a primitive double value.
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* @throws ClassCastException
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* if the element is of not a {@link JsonPrimitive} and is not a
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* valid double value.
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* @throws IllegalStateException
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* if the element is of the type {@link JsonArray} but contains more
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* than a single element.
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*/
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public double getAsDouble() {
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throw new UnsupportedOperationException(getClass().getSimpleName());
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}
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/**
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* convenience method to get this element as a primitive float value.
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*
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* @return get this element as a primitive float value.
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* @throws ClassCastException
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* if the element is of not a {@link JsonPrimitive} and is not a
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* valid float value.
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* @throws IllegalStateException
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* if the element is of the type {@link JsonArray} but contains more
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* than a single element.
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*/
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public float getAsFloat() {
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throw new UnsupportedOperationException(getClass().getSimpleName());
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}
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/**
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* convenience method to get this element as a primitive long value.
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*
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* @return get this element as a primitive long value.
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* @throws ClassCastException
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* if the element is of not a {@link JsonPrimitive} and is not a
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* valid long value.
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* @throws IllegalStateException
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* if the element is of the type {@link JsonArray} but contains more
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* than a single element.
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*/
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public long getAsLong() {
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throw new UnsupportedOperationException(getClass().getSimpleName());
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}
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/**
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* convenience method to get this element as a primitive integer value.
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*
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* @return get this element as a primitive integer value.
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* @throws ClassCastException
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* if the element is of not a {@link JsonPrimitive} and is not a
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* valid integer value.
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* @throws IllegalStateException
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* if the element is of the type {@link JsonArray} but contains more
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* than a single element.
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*/
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public int getAsInt() {
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throw new UnsupportedOperationException(getClass().getSimpleName());
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}
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/**
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* convenience method to get this element as a primitive byte value.
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*
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* @return get this element as a primitive byte value.
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* @throws ClassCastException
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* if the element is of not a {@link JsonPrimitive} and is not a
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* valid byte value.
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* @throws IllegalStateException
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* if the element is of the type {@link JsonArray} but contains more
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* than a single element.
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* @since 1.3
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*/
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public byte getAsByte() {
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throw new UnsupportedOperationException(getClass().getSimpleName());
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}
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/**
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* convenience method to get this element as a primitive character value.
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*
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* @return get this element as a primitive char value.
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* @throws ClassCastException
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* if the element is of not a {@link JsonPrimitive} and is not a
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* valid char value.
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* @throws IllegalStateException
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* if the element is of the type {@link JsonArray} but contains more
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* than a single element.
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* @since 1.3
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*/
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public char getAsCharacter() {
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throw new UnsupportedOperationException(getClass().getSimpleName());
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}
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/**
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* convenience method to get this element as a {@link BigDecimal}.
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*
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* @return get this element as a {@link BigDecimal}.
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* @throws ClassCastException
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* if the element is of not a {@link JsonPrimitive}. * @throws
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* NumberFormatException if the element is not a valid
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* {@link BigDecimal}.
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* @throws IllegalStateException
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* if the element is of the type {@link JsonArray} but contains more
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* than a single element.
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* @since 1.2
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*/
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public BigDecimal getAsBigDecimal() {
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throw new UnsupportedOperationException(getClass().getSimpleName());
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}
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/**
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* convenience method to get this element as a {@link BigInteger}.
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*
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* @return get this element as a {@link BigInteger}.
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* @throws ClassCastException
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* if the element is of not a {@link JsonPrimitive}.
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* @throws NumberFormatException
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* if the element is not a valid {@link BigInteger}.
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* @throws IllegalStateException
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* if the element is of the type {@link JsonArray} but contains more
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* than a single element.
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* @since 1.2
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*/
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public BigInteger getAsBigInteger() {
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throw new UnsupportedOperationException(getClass().getSimpleName());
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}
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/**
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* convenience method to get this element as a primitive short value.
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*
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* @return get this element as a primitive short value.
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* @throws ClassCastException
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* if the element is of not a {@link JsonPrimitive} and is not a
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* valid short value.
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* @throws IllegalStateException
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* if the element is of the type {@link JsonArray} but contains more
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* than a single element.
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*/
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public short getAsShort() {
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throw new UnsupportedOperationException(getClass().getSimpleName());
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}
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/**
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* Returns a String representation of this element.
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*/
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@Override
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public String toString() {
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try {
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StringWriter stringWriter = new StringWriter();
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JsonWriter jsonWriter = new JsonWriter(stringWriter);
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jsonWriter.setLenient(true);
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Streams.write(this, jsonWriter);
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return stringWriter.toString();
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} catch (IOException e) {
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throw new AssertionError(e);
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}
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}
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}
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