/*
* Copyright (C) 2008 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;
import java.io.IOException;
import java.math.BigDecimal;
import java.math.BigInteger;
/**
* A class representing a Json primitive value. A primitive value
* is either a String, a Java primitive, or a Java primitive
* wrapper type.
*
* @author Inderjeet Singh
* @author Joel Leitch
*/
public final class JsonPrimitive extends JsonElement {
private static final Class<?>[] PRIMITIVE_TYPES = { int.class, long.class, short.class,
float.class, double.class, byte.class, boolean.class, char.class, Integer.class, Long.class,
Short.class, Float.class, Double.class, Byte.class, Boolean.class, Character.class };
private static final BigInteger INTEGER_MAX = BigInteger.valueOf(Integer.MAX_VALUE);
private static final BigInteger LONG_MAX = BigInteger.valueOf(Long.MAX_VALUE);
private Object value;
/**
* Create a primitive containing a boolean value.
*
* @param bool the value to create the primitive with.
*/
public JsonPrimitive(Boolean bool) {
setValue(bool);
}
/**
* Create a primitive containing a {@link Number}.
*
* @param number the value to create the primitive with.
*/
public JsonPrimitive(Number number) {
setValue(number);
}
/**
* Create a primitive containing a String value.
*
* @param string the value to create the primitive with.
*/
public JsonPrimitive(String string) {
setValue(string);
}
/**
* Create a primitive containing a character. The character is turned into a one character String
* since Json only supports String.
*
* @param c the value to create the primitive with.
*/
public JsonPrimitive(Character c) {
setValue(c);
}
/**
* Create a primitive using the specified Object. It must be an instance of {@link Number}, a
* Java primitive type, or a String.
*
* @param primitive the value to create the primitive with.
*/
JsonPrimitive(Object primitive) {
setValue(primitive);
}
void setValue(Object primitive) {
if (primitive instanceof Character) {
// convert characters to strings since in JSON, characters are represented as a single
// character string
char c = ((Character) primitive).charValue();
this.value = String.valueOf(c);
} else {
Preconditions.checkArgument(primitive instanceof Number
|| isPrimitiveOrString(primitive));
this.value = primitive;
}
}
/**
* Check whether this primitive contains a boolean value.
*
* @return true if this primitive contains a boolean value, false otherwise.
*/
public boolean isBoolean() {
return value instanceof Boolean;
}
/**
* convenience method to get this element as a {@link Boolean}.
*
* @return get this element as a {@link Boolean}.
* @throws ClassCastException if the value contained is not a valid boolean value.
*/
@Override
Boolean getAsBooleanWrapper() {
return (Boolean) value;
}
/**
* convenience method to get this element as a boolean value.
*
* @return get this element as a primitive boolean value.
* @throws ClassCastException if the value contained is not a valid boolean value.
*/
@Override
public boolean getAsBoolean() {
if (isBoolean()) {
return getAsBooleanWrapper().booleanValue();
} else {
return Boolean.parseBoolean(getAsString());
}
}
/**
* Check whether this primitive contains a Number.
*
* @return true if this primitive contains a Number, false otherwise.
*/
public boolean isNumber() {
return value instanceof Number;
}
/**
* convenience method to get this element as a Number.
*
* @return get this element as a Number.
* @throws ClassCastException if the value contained is not a valid Number.
*/
@Override
public Number getAsNumber() {
return (Number) value;
}
/**
* Check whether this primitive contains a String value.
*
* @return true if this primitive contains a String value, false otherwise.
*/
public boolean isString() {
return value instanceof String;
}
/**
* convenience method to get this element as a String.
*
* @return get this element as a String.
* @throws ClassCastException if the value contained is not a valid String.
*/
@Override
public String getAsString() {
if (isNumber()) {
return getAsNumber().toString();
} else if (isBoolean()) {
return getAsBooleanWrapper().toString();
} else {
return (String) value;
}
}
/**
* convenience method to get this element as a primitive double.
*
* @return get this element as a primitive double.
* @throws ClassCastException if the value contained is not a valid double.
*/
@Override
public double getAsDouble() {
if (isNumber()) {
return getAsNumber().doubleValue();
} else {
return Double.parseDouble(getAsString());
}
}
/**
* convenience method to get this element as a {@link BigDecimal}.
*
* @return get this element as a {@link BigDecimal}.
* @throws NumberFormatException if the value contained is not a valid {@link BigDecimal}.
*/
@Override
public BigDecimal getAsBigDecimal() {
if (value instanceof BigDecimal) {
return (BigDecimal) value;
} else {
return new BigDecimal(value.toString());
}
}
/**
* convenience method to get this element as a {@link BigInteger}.
*
* @return get this element as a {@link BigInteger}.
* @throws NumberFormatException if the value contained is not a valid {@link BigInteger}.
*/
@Override
public BigInteger getAsBigInteger() {
if (value instanceof BigInteger) {
return (BigInteger) value;
} else {
return new BigInteger(value.toString());
}
}
/**
* convenience method to get this element as a float.
*
* @return get this element as a float.
* @throws ClassCastException if the value contained is not a valid float.
*/
@Override
public float getAsFloat() {
if (isNumber()) {
return getAsNumber().floatValue();
} else {
return Float.parseFloat(getAsString());
}
}
/**
* convenience method to get this element as a primitive long.
*
* @return get this element as a primitive long.
* @throws ClassCastException if the value contained is not a valid long.
*/
@Override
public long getAsLong() {
if (isNumber()) {
return getAsNumber().longValue();
} else {
return Long.parseLong(getAsString());
}
}
/**
* convenience method to get this element as a primitive short.
*
* @return get this element as a primitive short.
* @throws ClassCastException if the value contained is not a valid short value.
*/
@Override
public short getAsShort() {
if (isNumber()) {
return getAsNumber().shortValue();
} else {
return Short.parseShort(getAsString());
}
}
/**
* convenience method to get this element as a primitive integer.
*
* @return get this element as a primitive integer.
* @throws ClassCastException if the value contained is not a valid integer.
*/
@Override
public int getAsInt() {
if (isNumber()) {
return getAsNumber().intValue();
} else {
return Integer.parseInt(getAsString());
}
}
@Override
public byte getAsByte() {
if (isNumber()) {
return getAsNumber().byteValue();
} else {
return Byte.parseByte(getAsString());
}
}
@Override
public char getAsCharacter() {
return getAsString().charAt(0);
}
/**
* convenience method to get this element as an Object.
*
* @return get this element as an Object that can be converted to a suitable value.
*/
@Override
Object getAsObject() {
if (value instanceof BigInteger) {
BigInteger big = (BigInteger) value;
if (big.compareTo(INTEGER_MAX) < 0) {
return big.intValue();
} else if (big.compareTo(LONG_MAX) < 0) {
return big.longValue();
}
}
// No need to convert to float or double since those lose precision
return value;
}
@Override
protected void toString(Appendable sb, Escaper escaper) throws IOException {
if (isString()) {
sb.append('"');
sb.append(escaper.escapeJsonString(value.toString()));
sb.append('"');
} else {
sb.append(value.toString());
}
}
private static boolean isPrimitiveOrString(Object target) {
if (target instanceof String) {
return true;
}
Class<?> classOfPrimitive = target.getClass();
for (Class<?> standardPrimitive : PRIMITIVE_TYPES) {
if (standardPrimitive.isAssignableFrom(classOfPrimitive)) {
return true;
}
}
return false;
}
@Override
public int hashCode() {
if (value == null) {
return 31;
}
// Using recommended hashing algorithm from Effective Java for longs and doubles
if (isIntegral(this)) {
long value = getAsNumber().longValue();
return (int) (value ^ (value >>> 32));
}
if (isFloatingPoint(this)) {
long value = Double.doubleToLongBits(getAsNumber().doubleValue());
return (int) (value ^ (value >>> 32));
}
return value.hashCode();
}
@Override
public boolean equals(Object obj) {
if (this == obj) {
return true;
}
if (obj == null || getClass() != obj.getClass()) {
return false;
}
JsonPrimitive other = (JsonPrimitive)obj;
if (value == null) {
return other.value == null;
}
if (isIntegral(this) && isIntegral(other)) {
return getAsNumber().longValue() == other.getAsNumber().longValue();
}
if (isFloatingPoint(this) && isFloatingPoint(other)) {
return getAsNumber().doubleValue() == other.getAsNumber().doubleValue();
}
return value.equals(other.value);
}
/**
* Returns true if the specified number is an integral type
* (Long, Integer, Short, Byte, BigInteger)
*/
private static boolean isIntegral(JsonPrimitive primitive) {
if (primitive.value instanceof Number) {
Number number = (Number) primitive.value;
return number instanceof BigInteger || number instanceof Long || number instanceof Integer
|| number instanceof Short || number instanceof Byte;
}
return false;
}
/**
* Returns true if the specified number is a floating point type (BigDecimal, double, float)
*/
private static boolean isFloatingPoint(JsonPrimitive primitive) {
if (primitive.value instanceof Number) {
Number number = (Number) primitive.value;
return number instanceof BigDecimal || number instanceof Double || number instanceof Float;
}
return false;
}
}