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A minimal JSON parser and writer
package info.freelibrary.json;
import static info.freelibrary.util.Constants.EMPTY;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;
import java.util.ListIterator;
import java.util.NoSuchElementException;
import java.util.Objects;
import java.util.Optional;
import java.util.OptionalDouble;
import java.util.OptionalInt;
import java.util.OptionalLong;
import info.freelibrary.json.JsonObject.Property;
/**
* Represents a JSON object, a set of name/value pairs, where the names are strings and the values are JSON values.
*
* Properties can be added using the add(String, ...) methods which accept instances of {@link JsonValue},
* strings, primitive numbers, and boolean values. To modify certain values of an object, use the
* set(String, ...) methods. Please note that the add methods are faster than set
* as they do not search for existing properties. On the other hand, the add methods do not prevent adding
* multiple properties with the same name. Duplicate names are discouraged but not prohibited by JSON.
*
*
* Properties can be accessed by their name using {@link #get(String)}. A list of all names can be obtained from the
* method {@link #names()}. This class also supports iterating over the properties in document order using an
* {@link #iterator()} or an enhanced for loop:
*
*
*
* for (Property property : jsonObject) {
* String name = property.getName();
* JsonValue value = property.getValue();
* ...
* }
*
*
* Even though JSON objects are unordered by definition, instances of this class preserve the order of properties to
* allow processing in document order and to guarantee a predictable output.
*
*
* Note that this class is not thread-safe. If multiple threads access a JsonObject
* instance concurrently, while at least one of these threads modifies the contents of this object, access to the
* instance must be synchronized externally. Failure to do so may lead to an inconsistent state.
*
*
* This class is not supposed to be extended by clients.
*
*/
public final class JsonObject extends JsonValue implements Iterable {
/**
* The serialVersionUID for JsonObject.
*/
private static final long serialVersionUID = -7137647142842370219L;
/**
* A list of property names.
*/
private final List myNames;
/**
* A list of property values.
*/
private final List myValues;
/**
* A hash code table.
*/
private transient HashCodeTable myTable;
/**
* Creates a new empty JsonObject.
*/
public JsonObject() {
myNames = new ArrayList<>();
myValues = new ArrayList<>();
myTable = new HashCodeTable();
}
/**
* Creates a new JsonObject, initialized with the contents of the specified JSON object.
*
* @param aObject the JSON object to get the initial contents from, must not be null
*/
public JsonObject(final JsonObject aObject) {
this(aObject, false);
}
/**
* Creates a new JsonObject that can be unmodifiable, if desired.
*
* @param aObject A JSON object
* @param aUnmodifiable Whether the newly created JsonObject should be unmodifiable
*/
private JsonObject(final JsonObject aObject, final boolean aUnmodifiable) {
Objects.requireNonNull(aObject, "object is null");
if (aUnmodifiable) {
myNames = Collections.unmodifiableList(aObject.myNames);
myValues = Collections.unmodifiableList(aObject.myValues);
} else {
myNames = new ArrayList<>(aObject.myNames);
myValues = new ArrayList<>(aObject.myValues);
}
myTable = new HashCodeTable();
updateHashIndex();
}
/**
* Returns an unmodifiable JsonObject for the specified one. This method allows read-only access to a JsonObject.
*
* The returned JsonObject is backed by the given object and reflect changes that happen to it. Attempts to modify
* the returned JsonObject result in an UnsupportedOperationException.
*
*
* @param aObject the JsonObject for which an unmodifiable JsonObject is to be returned
* @return an unmodifiable view of the specified JsonObject
*/
public static JsonObject unmodifiableObject(final JsonObject aObject) {
return new JsonObject(aObject, true);
}
/**
* Appends a new property to the end of this object, with the specified name and the JSON representation of the
* specified int value.
*
* This method does not prevent duplicate names. Calling this method with a name that already
* exists in the object will append another property with the same name. In order to replace existing properties,
* use the method set(name, value) instead. However, add is much faster than
* set (because it does not need to search for existing properties). Therefore add should
* be preferred when constructing new objects.
*
*
* @param aName The name of the property to add
* @param aValue The value of the property to add
* @return The object itself, to enable method chaining
*/
public JsonObject add(final String aName, final int aValue) {
return add(aName, Json.value(aValue));
}
/**
* Appends a new property to the end of this object, with the specified name and the JSON representation of the
* specified long value.
*
* This method does not prevent duplicate names. Calling this method with a name that already
* exists in the object will append another property with the same name. In order to replace existing properties,
* use the method set(name, value) instead. However, add is much faster than
* set (because it does not need to search for existing properties). Therefore add should
* be preferred when constructing new objects.
*
*
* @param aName The name of the property to add
* @param aValue The value of the property to add
* @return The object itself, to enable method chaining
*/
public JsonObject add(final String aName, final long aValue) {
return add(aName, Json.value(aValue));
}
/**
* Appends a new property to the end of this object, with the specified name and the JSON representation of the
* specified float value.
*
* This method does not prevent duplicate names. Calling this method with a name that already
* exists in the object will append another property with the same name. In order to replace existing properties,
* use the method set(name, value) instead. However, add is much faster than
* set (because it does not need to search for existing properties). Therefore add should
* be preferred when constructing new objects.
*
*
* @param aName The name of the property to add
* @param aValue The value of the property to add
* @return The object itself, to enable method chaining
*/
public JsonObject add(final String aName, final float aValue) {
return add(aName, Json.value(aValue));
}
/**
* Appends a new property to the end of this object, with the specified name and the JSON representation of the
* specified double value.
*
* This method does not prevent duplicate names. Calling this method with a name that already
* exists in the object will append another property with the same name. In order to replace existing properties,
* use the method set(name, value) instead. However, add is much faster than
* set (because it does not need to search for existing properties). Therefore add should
* be preferred when constructing new objects.
*
*
* @param aName The name of the property to add
* @param aValue The value of the property to add
* @return The object itself, to enable method chaining
*/
public JsonObject add(final String aName, final double aValue) {
return add(aName, Json.value(aValue));
}
/**
* Appends a new property to the end of this object, with the specified name and the JSON representation of the
* specified boolean value.
*
* This method does not prevent duplicate names. Calling this method with a name that already
* exists in the object will append another property with the same name. In order to replace existing properties,
* use the method set(name, value) instead. However, add is much faster than
* set (because it does not need to search for existing properties). Therefore add should
* be preferred when constructing new objects.
*
*
* @param aName The name of the property to add
* @param aValue The value of the property to add
* @return The object itself, to enable method chaining
*/
public JsonObject add(final String aName, final boolean aValue) {
return add(aName, Json.value(aValue));
}
/**
* Appends a new property to the end of this object, with the specified name and the JSON representation of the
* specified string.
*
* This method does not prevent duplicate names. Calling this method with a name that already
* exists in the object will append another property with the same name. In order to replace existing properties,
* use the method set(name, value) instead. However, add is much faster than
* set (because it does not need to search for existing properties). Therefore add should
* be preferred when constructing new objects.
*
*
* @param aName The name of the property to add
* @param aValue The value of the property to add
* @return The object itself, to enable method chaining
*/
public JsonObject add(final String aName, final String aValue) {
return add(aName, Json.value(aValue));
}
/**
* Appends a new property to the end of this object, with the specified name and supplied JSON object.
*
* This method does not prevent duplicate names. Calling this method with a name that already
* exists in the object will append another property with the same name. In order to replace existing properties,
* use the method set(name, value) instead. However, add is much faster than
* set (because it does not need to search for existing properties). Therefore add should
* be preferred when constructing new objects.
*
*
* @param aName The name of the property to add
* @param aObject The value of the property to add
* @return The object itself, to enable method chaining
*/
public JsonObject add(final String aName, final JsonObject aObject) {
return add(aName, (JsonValue) aObject);
}
/**
* Appends a new property to the end of this object, with the specified name and supplied JSON array.
*
* This method does not prevent duplicate names. Calling this method with a name that already
* exists in the object will append another property with the same name. In order to replace existing properties,
* use the method set(name, value) instead. However, add is much faster than
* set (because it does not need to search for existing properties). Therefore add should
* be preferred when constructing new objects.
*
*
* @param aName The name of the property to add
* @param aArray The value of the property to add
* @return The object itself, to enable method chaining
*/
public JsonObject add(final String aName, final JsonArray aArray) {
return add(aName, (JsonValue) aArray);
}
/**
* Appends a new property to the end of this object, with the specified name and the specified JSON value.
*
* This method does not prevent duplicate names. Calling this method with a name that already
* exists in the object will append another property with the same name. In order to replace existing properties,
* use the method set(name, value) instead. However, add is much faster than
* set (because it does not need to search for existing properties). Therefore add should
* be preferred when constructing new objects.
*
*
* @param aName The name of the property to add
* @param aValue The value of the property to add, must not be null
* @return The object itself, to enable method chaining
*/
protected JsonObject add(final String aName, final JsonValue aValue) {
Objects.requireNonNull(aName, "name is null");
Objects.requireNonNull(aValue, "value is null");
myTable.add(aName, myNames.size());
myNames.add(aName);
myValues.add(aValue);
return this;
}
/**
* Sets the value of the property with the specified name to the JSON representation of the specified
* int value. If this object does not contain a property with this name, a new property is added at the
* end of the object. If this object contains multiple properties with this name, only the last one is changed.
*
* This method should only be used to modify existing objects. To fill a new object with
* properties, the method add(name, value) should be preferred which is much faster (as it does not
* need to search for existing properties).
*
*
* @param aName The name of the property to replace
* @param aValue The value to set to the property
* @return The object itself, to enable method chaining
*/
public JsonObject set(final String aName, final int aValue) {
return set(aName, Json.value(aValue));
}
/**
* Sets the value of the property with the specified name to the JSON representation of the specified
* long value. If this object does not contain a property with this name, a new property is added at
* the end of the object. If this object contains multiple properties with this name, only the last one is changed.
*
* This method should only be used to modify existing objects. To fill a new object with
* properties, the method add(name, value) should be preferred which is much faster (as it does not
* need to search for existing properties).
*
*
* @param aName The name of the property to replace
* @param aValue The value to set to the property
* @return The object itself, to enable method chaining
*/
public JsonObject set(final String aName, final long aValue) {
return set(aName, Json.value(aValue));
}
/**
* Sets the value of the property with the specified name to the JSON representation of the specified
* float value. If this object does not contain a property with this name, a new property is added at
* the end of the object. If this object contains multiple properties with this name, only the last one is changed.
*
* This method should only be used to modify existing objects. To fill a new object with
* properties, the method add(name, value) should be preferred which is much faster (as it does not
* need to search for existing properties).
*
*
* @param aName The name of the property to add
* @param aValue The value of the property to add
* @return The object itself, to enable method chaining
*/
public JsonObject set(final String aName, final float aValue) {
return set(aName, Json.value(aValue));
}
/**
* Sets the value of the property with the specified name to the JSON representation of the specified
* double value. If this object does not contain a property with this name, a new property is added at
* the end of the object. If this object contains multiple properties with this name, only the last one is changed.
*
* This method should only be used to modify existing objects. To fill a new object with
* properties, the method add(name, value) should be preferred which is much faster (as it does not
* need to search for existing properties).
*
*
* @param aName The name of the property to add
* @param aValue The value of the property to add
* @return The object itself, to enable method chaining
*/
public JsonObject set(final String aName, final double aValue) {
set(aName, Json.value(aValue));
return this;
}
/**
* Sets the value of the property with the specified name to the JSON representation of the specified
* boolean value. If this object does not contain a property with this name, a new property is added at
* the end of the object. If this object contains multiple properties with this name, only the last one is changed.
*
* This method should only be used to modify existing objects. To fill a new object with
* properties, the method add(name, value) should be preferred which is much faster (as it does not
* need to search for existing properties).
*
*
* @param aName The name of the property to add
* @param aValue The value of the property to add
* @return The object itself, to enable method chaining
*/
public JsonObject set(final String aName, final boolean aValue) {
return set(aName, Json.value(aValue));
}
/**
* Sets the value of the property with the specified name to the JSON representation of the specified string. If
* this object does not contain a property with this name, a new property is added at the end of the object. If this
* object contains multiple properties with this myName, only the last one is changed.
*
* This method should only be used to modify existing objects. To fill a new object with
* properties, the method add(name, value) should be preferred which is much faster (as it does not
* need to search for existing properties).
*
*
* @param aName The name of the property to add
* @param aValue The value of the property to add
* @return The object itself, to enable method chaining
*/
public JsonObject set(final String aName, final String aValue) {
return set(aName, Json.value(aValue));
}
/**
* Sets the value of the property with the specified name to the specified JSON value. If this object does not
* contain a property with this name, a new property is added at the end of the object. If this object contains
* multiple properties with this name, only the last one is changed.
*
* This method should only be used to modify existing objects. To fill a new object with
* properties, the method add(name, value) should be preferred which is much faster (as it does not
* need to search for existing properties).
*
*
* @param aName The name of the property to add
* @param aValue The value of the property to add, must not be null
* @return The object itself, to enable method chaining
*/
public JsonObject set(final String aName, final JsonValue aValue) {
Objects.requireNonNull(aName, "name is null");
Objects.requireNonNull(aValue, "value is null");
final int index = indexOf(aName);
if (index != -1) {
myValues.set(index, aValue);
} else {
myTable.add(aName, myNames.size());
myNames.add(aName);
myValues.add(aValue);
}
return this;
}
/**
* Removes a property with the specified name from this object. If this object contains multiple properties with the
* given name, only the last one is removed. If this object does not contain a property with the specified name, the
* object is not modified.
*
* @param aName The name of the property to remove
* @return The object itself, to enable method chaining
*/
public JsonObject remove(final String aName) {
Objects.requireNonNull(aName, "name is null");
final int index = indexOf(aName);
if (index != -1) {
myTable.remove(index);
myNames.remove(index);
myValues.remove(index);
}
return this;
}
/**
* Checks if a specified property is present as a child of this object. This will not test if this object contains
* the literal null, {@link JsonValue#isNull()} should be used for this purpose.
*
* @param aName The name of the property to check for
* @return Whether or not the property is present
*/
public boolean contains(final String aName) {
return myNames.contains(aName);
}
/**
* Copies all properties of the specified object into this object. When the specified object contains properties
* with names that also exist in this object, the existing values in this object will be replaced by the
* corresponding values in the specified object.
*
* @param aObject The object to merge
* @return The object itself, to enable method chaining
*/
public JsonObject merge(final JsonObject aObject) {
Objects.requireNonNull(aObject, "object is null");
for (final Property property : aObject) {
set(property.myName, property.myValue);
}
return this;
}
/**
* Returns the value of the property with the specified name in this object. If this object contains multiple
* properties with the given name, this method will return the last one.
*
* @param aName The name of the property whose value is to be returned
* @return An Optional with the value of the last property with the specified name, or an empty Optional if this
* object does not contain a property with that name
*/
public Optional get(final String aName) {
return Optional.ofNullable(getJsonValue(aName));
}
/**
* Returns an optional JsonObject property value that's associated with the supplied property name. If this object
* contains multiple properties with the given name, this method will return the last one. If it doesn't have any
* properties with the given name, an empty Optional is returned.
*
* @param aName The name of the JsonObject property to be returned
* @return An Optional with the value of the last property with the specified name, or an empty Optional if this
* object does not contain a property with that name
*/
public Optional getJsonObject(final String aName) {
final JsonValue value = getJsonValue(aName);
return value != null ? Optional.of(value.asObject()) : Optional.empty();
}
/**
* Returns the JsonObject property value that's associated with the supplied property name. If this object doesn't
* contain a property with the supplied name, the passed in default value is returned instead.
*
* @param aName The name of the JsonObject property to be returned
* @param aDefaultValue The default value returned if the JsonObject doesn't have a property with the supplied name
* @return The requested JsonObject or the supplied default value
*/
public JsonObject getJsonObject(final String aName, final JsonObject aDefaultValue) {
final JsonValue value = getJsonValue(aName);
return value != null ? value.asObject() : aDefaultValue;
}
/**
* Returns an optional JsonArray property value that's associated with the supplied property name. If this object
* contains multiple properties with the given name, this method will return the last one. If it doesn't have any
* properties with the given name, an empty Optional is returned.
*
* @param aName The name of the JsonArray property to be returned
* @return An Optional with the value of the last property with the specified name, or an empty Optional if this
* object does not contain a property with that name
*/
public Optional getJsonArray(final String aName) {
final JsonValue value = getJsonValue(aName);
return value != null ? Optional.of(value.asArray()) : Optional.empty();
}
/**
* Returns the JsonArray property value that's associated with the supplied property name. If this object doesn't
* contain a property with the supplied name, the pass in default value is returned instead.
*
* @param aName The name of the JsonArray property to be returned
* @param aDefaultValue The default value returned if the JsonObject doesn't have a property with the supplied name
* @return The requested JsonArray or the supplied default value
*/
public JsonArray getJsonArray(final String aName, final JsonArray aDefaultValue) {
final JsonValue value = getJsonValue(aName);
return value != null ? value.asArray() : aDefaultValue;
}
/**
* Returns the int value of the property with the specified name in this object. If this object does
* not contain a property with this name, the given default value is returned. If this object contains multiple
* properties with the given name, the last one will be picked. If this property's value does not represent a JSON
* number or if it cannot be interpreted as Java int, an exception is thrown.
*
* @param aName The name of the property whose value is to be returned
* @param aDefaultValue The value to be returned if the requested property is missing
* @return The value of the last property with the specified name, or the given default value if this object does
* not contain a property with that name
*/
public int getInt(final String aName, final int aDefaultValue) {
final JsonValue value = getJsonValue(aName);
return value != null ? value.asInt() : aDefaultValue;
}
/**
* Returns the optional int value of the property with the specified name in this object. If this
* object does not contain a property with this name, an empty optional is returned. If this object contains
* multiple properties with the given name, the last one will be picked. If this property's value does not represent
* a JSON number or if it cannot be interpreted as Java int, an exception is thrown.
*
* @param aName The name of the property whose value is to be returned
* @return The value of the last property with the specified name, or an empty optional if this object does not
* contain a property with that name
*/
public OptionalInt getInt(final String aName) {
final JsonValue value = getJsonValue(aName);
return value != null ? OptionalInt.of(value.asInt()) : OptionalInt.empty();
}
/**
* Returns the long value of the property with the specified name in this object. If this object does
* not contain a property with this name, the given default value is returned. If this object contains multiple
* properties with the given name, the last one will be picked. If this property's value does not represent a JSON
* number or if it cannot be interpreted as Java long, an exception is thrown.
*
* @param aName The name of the property whose value is to be returned
* @param aDefaultValue The value to be returned if the requested property is missing
* @return The value of the last property with the specified name, or the given default value if this object does
* not contain a property with that name
*/
public long getLong(final String aName, final long aDefaultValue) {
final JsonValue value = getJsonValue(aName);
return value != null ? value.asLong() : aDefaultValue;
}
/**
* Returns the optional long value of the property with the specified name in this object. If this
* object does not contain a property with this name, an empty optional is returned. If this object contains
* multiple properties with the given name, the last one will be picked. If this property's value does not represent
* a JSON number or if it cannot be interpreted as Java long, an exception is thrown.
*
* @param aName The name of the property whose value is to be returned
* @return The value of the last property with the specified name, or an empty optional if this object does not
* contain a property with that name
*/
public OptionalLong getLong(final String aName) {
final JsonValue value = getJsonValue(aName);
return value != null ? OptionalLong.of(value.asLong()) : OptionalLong.empty();
}
/**
* Returns the float value of the property with the specified name in this object. If this object does
* not contain a property with this name, the given default value is returned. If this object contains multiple
* properties with the given name, the last one will be picked. If this property's value does not represent a JSON
* number or if it cannot be interpreted as Java float, an exception is thrown.
*
* @param aName The name of the property whose value is to be returned
* @param aDefaultValue The value to be returned if the requested property is missing
* @return The value of the last property with the specified name, or the given default value if this object does
* not contain a property with that name
*/
public float getFloat(final String aName, final float aDefaultValue) {
final JsonValue value = getJsonValue(aName);
return value != null ? value.asFloat() : aDefaultValue;
}
/**
* Returns the optional float value of the property with the specified name in this object. If this
* object does not contain a property with this name, an empty optional is returned. If this object contains
* multiple properties with the given name, the last one will be picked. If this property's value does not represent
* a JSON number or if it cannot be interpreted as Java float, an exception is thrown.
*
* @param aName The name of the property whose value is to be returned
* @return The value of the last property with the specified name, or an empty optional if this object does not
* contain a property with that name
*/
public Optional getFloat(final String aName) {
final JsonValue value = getJsonValue(aName);
return value != null ? Optional.of(value.asFloat()) : Optional.empty();
}
/**
* Returns the double value of the property with the specified name in this object. If this object does
* not contain a property with this name, the given default value is returned. If this object contains multiple
* properties with the given name, the last one will be picked. If this property's value does not represent a JSON
* number or if it cannot be interpreted as Java double, an exception is thrown.
*
* @param aName The name of the property whose value is to be returned
* @param aDefaultValue the value to be returned if the requested property is missing
* @return The value of the last property with the specified name, or the given default value if this object does
* not contain a property with that name
*/
public double getDouble(final String aName, final double aDefaultValue) {
final JsonValue value = getJsonValue(aName);
return value != null ? value.asDouble() : aDefaultValue;
}
/**
* Returns the optional double value of the property with the specified name in this object. If this
* object does not contain a property with this name, an empty optional is returned. If this object contains
* multiple properties with the given name, the last one will be picked. If this property's value does not represent
* a JSON number or if it cannot be interpreted as Java double, an exception is thrown.
*
* @param aName The name of the property whose value is to be returned
* @return The value of the last property with the specified name, or an empty optional if this object does not
* contain a property with that name
*/
public OptionalDouble getDouble(final String aName) {
final JsonValue value = getJsonValue(aName);
return value != null ? OptionalDouble.of(value.asDouble()) : OptionalDouble.empty();
}
/**
* Returns the boolean value of the property with the specified name in this object. If this object
* does not contain a property with this name, the given default value is returned. If this object contains multiple
* properties with the given name, the last one will be picked. If this property's value does not represent a JSON
* true or false value, an exception is thrown.
*
* @param aName The name of the property whose value is to be returned
* @param aDefaultValue The value to be returned if the requested property is missing
* @return The value of the last property with the specified name, or the given default value if this object does
* not contain a property with that name
*/
public boolean getBoolean(final String aName, final boolean aDefaultValue) {
final JsonValue value = getJsonValue(aName);
return value != null ? value.asBoolean() : aDefaultValue;
}
/**
* Returns the optional boolean value of the property with the specified name in this object. If this
* object does not contain a property with this name, an empty optional is returned. If this object contains
* multiple properties with the given name, the last one will be picked. If this property's value does not represent
* a JSON number or if it cannot be interpreted as Java boolean, an exception is thrown.
*
* @param aName The name of the property whose value is to be returned
* @return The value of the last property with the specified name, or an empty optional if this object does not
* contain a property with that name
*/
public Optional getBoolean(final String aName) {
final JsonValue value = getJsonValue(aName);
return value != null ? Optional.of(value.asBoolean()) : Optional.empty();
}
/**
* Returns the String value of the property with the specified name in this object. If this object does
* not contain a property with this name, the given default value is returned. If this object contains multiple
* properties with the given name, the last one is picked. If this property's value does not represent a JSON
* string, an exception is thrown.
*
* @param aName The name of the property whose value is to be returned
* @param aDefaultValue The value to be returned if the requested property is missing
* @return The value of the last property with the specified name, or the given default value if this object does
* not contain a property with that name
*/
public String getString(final String aName, final String aDefaultValue) {
final JsonValue value = getJsonValue(aName);
return value != null ? value.asString() : aDefaultValue;
}
/**
* Returns the optional String value of the property with the specified name in this object. If this
* object does not contain a property with this name, an empty optional is returned. If this object contains
* multiple properties with the given name, the last one will be picked. If this property's value does not represent
* a JSON string, an exception is thrown.
*
* @param aName The name of the property whose value is to be returned
* @return The value of the last property with the specified name, or an empty optional if this object does not
* contain a property with that name
*/
public Optional getString(final String aName) {
final JsonValue value = getJsonValue(aName);
return value != null ? Optional.of(value.asString()) : Optional.empty();
}
/**
* Returns the number of properties (name/value pairs) in this object.
*
* @return The number of properties in this object
*/
public int size() {
return myNames.size();
}
/**
* Returns true if this object contains no properties.
*
* @return True if this object contains no properties; else, false
*/
public boolean isEmpty() {
return myNames.isEmpty();
}
/**
* Returns a list of the names in this object in document order. The returned list is backed by this object and will
* reflect subsequent changes. It cannot be used to modify this object. Attempts to modify the returned list will
* result in an exception.
*
* @return A list of the names in this object
*/
public List names() {
return Collections.unmodifiableList(myNames);
}
/**
* Returns an iterator over the properties of this object in document order. The returned iterator cannot be used to
* modify this object.
*
* @return An iterator over the properties of this object
*/
@Override
public ListIterator iterator() {
final ListIterator namesIterator = myNames.listIterator();
final ListIterator valuesIterator = myValues.listIterator();
return new ListIterator<>() {
@Override
public boolean hasNext() {
return namesIterator.hasNext();
}
@Override
public Property next() {
if (!hasNext()) {
throw new NoSuchElementException("JsonObject doesn't have another property");
}
return new Property(namesIterator.next(), valuesIterator.next());
}
@Override
public void remove() {
throw new UnsupportedOperationException();
}
@Override
public void add(final Property aProperty) {
throw new UnsupportedOperationException();
}
@Override
public boolean hasPrevious() {
return namesIterator.hasPrevious();
}
@Override
public int nextIndex() {
return namesIterator.nextIndex();
}
@Override
public Property previous() {
return new Property(namesIterator.previous(), valuesIterator.next());
}
@Override
public int previousIndex() {
return namesIterator.previousIndex();
}
@Override
public void set(final Property arg0) {
throw new UnsupportedOperationException();
}
};
}
@Override
void write(final JsonWriter aWriter) throws IOException {
aWriter.writeObjectOpen();
if (aWriter instanceof SortingWriter) {
final Iterator iterator = sortedIterator();
if (iterator.hasNext()) {
Property property = iterator.next();
aWriter.writeMemberName(property.getName());
aWriter.writeMemberSeparator();
property.getValue().write(aWriter);
while (iterator.hasNext()) {
property = iterator.next();
aWriter.writeObjectSeparator();
aWriter.writeMemberName(property.getName());
aWriter.writeMemberSeparator();
property.getValue().write(aWriter);
}
}
} else {
final Iterator namesIterator = myNames.iterator();
final Iterator valuesIterator = myValues.iterator();
if (namesIterator.hasNext()) {
aWriter.writeMemberName(namesIterator.next());
aWriter.writeMemberSeparator();
valuesIterator.next().write(aWriter);
while (namesIterator.hasNext()) {
aWriter.writeObjectSeparator();
aWriter.writeMemberName(namesIterator.next());
aWriter.writeMemberSeparator();
valuesIterator.next().write(aWriter);
}
}
}
aWriter.writeObjectClose();
}
@Override
public boolean isObject() {
return true;
}
@Override
public JsonObject asObject() {
return this;
}
@Override
public int hashCode() {
int result = 1;
result = 31 * result + myNames.hashCode();
return 31 * result + myValues.hashCode();
}
@Override
public boolean equals(final Object aObject) {
final JsonObject jsonObject;
if (this == aObject) {
return true;
}
if (aObject == null || getClass() != aObject.getClass()) {
return false;
}
jsonObject = (JsonObject) aObject;
return myNames.equals(jsonObject.myNames) && myValues.equals(jsonObject.myValues);
}
@Override
public boolean equals(final JsonValue aValue, final JsonOptions aConfig) {
return ValueUtils.equals(EMPTY, this, aValue, aConfig);
}
/**
* Gets the index of the supplied property name.
*
* @param aName A property name
* @return The index position of the last entry with the supplied name
*/
int indexOf(final String aName) {
final int index = myTable.get(aName);
if (index != -1 && aName.equals(myNames.get(index))) {
return index;
}
return myNames.lastIndexOf(aName);
}
/**
* Iterates through the JsonObject's contents in a sorted fashion.
*
* @return An iterator that iterates over the JsonObject's sorted contents
*/
Iterator sortedIterator() {
final List names = new ArrayList<>(myNames);
// Sort the JsonObject's property names
Collections.sort(names);
/**
* The sorted iterator.
*/
return new Iterator<>() {
/**
* The sorted iterator's index position.
*/
private int myCurrentIndex;
@Override
public boolean hasNext() {
return myCurrentIndex < names.size();
}
@Override
public Property next() {
final String name = names.get(myCurrentIndex++);
return new Property(name, myValues.get(myNames.indexOf(name)));
}
};
}
/**
* Reads the object input stream.
*
* @param aInputStream An object stream
* @throws IOException If there is trouble reading the object stream
* @throws ClassNotFoundException If the class of the object stream cannot be found
*/
private synchronized void readObject(final ObjectInputStream aInputStream)
throws IOException, ClassNotFoundException {
aInputStream.defaultReadObject();
myTable = new HashCodeTable();
updateHashIndex();
}
/**
* Updates the object's hash index.
*/
private void updateHashIndex() {
final int size = myNames.size();
for (int index = 0; index < size; index++) {
myTable.add(myNames.get(index), index);
}
}
/**
* Returns the value of the property with the specified name in this object. If this object contains multiple
* properties with the given name, this method will return the last one.
*
* @param aName The name of the property whose value is to be returned
* @return The value of the last property with the specified name, or null if this object does not
* contain a property with that name
*/
private JsonValue getJsonValue(final String aName) {
final int index = indexOf(Objects.requireNonNull(aName, "name is null"));
return index != -1 ? myValues.get(index) : null;
}
/**
* Represents a JSON object property, i.e. a name and value.
*/
public static class Property {
/**
* The name of the JSON object's property.
*/
private final String myName;
/**
* The value of the JSON object's property.
*/
private final JsonValue myValue;
/**
* Creates a new JSON object property.
*
* @param aName A property name
* @param aValue A property string value
*/
Property(final String aName, final String aValue) {
this(aName, Json.value(aValue));
}
/**
* Creates a new JSON object property.
*
* @param aName A property name
* @param aValue A property integer value
*/
Property(final String aName, final int aValue) {
this(aName, Json.value(aValue));
}
/**
* Creates a new JSON object property.
*
* @param aName A property name
* @param aValue A property long value
*/
Property(final String aName, final long aValue) {
this(aName, Json.value(aValue));
}
/**
* Creates a new JSON object property.
*
* @param aName A property name
* @param aValue A property float value
*/
Property(final String aName, final float aValue) {
this(aName, Json.value(aValue));
}
/**
* Creates a new JSON object property.
*
* @param aName A property name
* @param aValue A property double value
*/
Property(final String aName, final double aValue) {
this(aName, Json.value(aValue));
}
/**
* Creates a new JSON object property.
*
* @param aName A property name
* @param aValue A property boolean value
*/
Property(final String aName, final boolean aValue) {
this(aName, Json.value(aValue));
}
/**
* Creates a new JSON object property.
*
* @param aName A property name
* @param aValue A property JSON array value
*/
Property(final String aName, final JsonArray aValue) {
this(aName, (JsonValue) aValue);
}
/**
* Creates a new JSON object property.
*
* @param aName A property name
* @param aValue A property JSON object value
*/
Property(final String aName, final JsonObject aValue) {
this(aName, (JsonValue) aValue);
}
/**
* Creates a new JSON object property.
*
* @param aName A property name
* @param aValue A property value
*/
private Property(final String aName, final JsonValue aValue) {
myName = aName;
myValue = aValue;
}
/**
* Returns the name of this property.
*
* @return the name of this property, never null
*/
public String getName() {
return myName;
}
/**
* Returns the value of this property if it's a string. If the value isn't a string, an
* UnsupportedOperationException is thrown.
*
* @return The string value of this property
* @throws UnsupportedOperationException If the property's value isn't a string
*/
public String getString() {
return myValue.asString();
}
/**
* Returns the value of this property if it's an integer. If the value isn't an integer, an
* UnsupportedOperationException is thrown.
*
* @return The integer value of this property
* @throws UnsupportedOperationException If the property's value isn't an integer
*/
public int getInt() {
return myValue.asInt();
}
/**
* Returns the value of this property if it's a long. If the value isn't a long, an
* UnsupportedOperationException is thrown.
*
* @return The long value of this property
* @throws UnsupportedOperationException If the property's value isn't a long
*/
public long getLong() {
return myValue.asLong();
}
/**
* Returns the value of this property if it's a float. If the value isn't a float, an
* UnsupportedOperationException is thrown.
*
* @return The float value of this property
* @throws UnsupportedOperationException If the property's value isn't a float
*/
public float getFloat() {
return myValue.asFloat();
}
/**
* Returns the value of this property if it's a double. If the value isn't a double, an
* UnsupportedOperationException is thrown.
*
* @return The double value of this property
* @throws UnsupportedOperationException If the property's value isn't a double
*/
public double getDouble() {
return myValue.asDouble();
}
/**
* Returns the value of this property if it's a boolean. If the value isn't a boolean, an
* UnsupportedOperationException is thrown.
*
* @return The boolean value of this property
* @throws UnsupportedOperationException If the property's value isn't a boolean
*/
public boolean getBoolean() {
return myValue.asBoolean();
}
/**
* Returns the value of this property if it's a JsonObject. If the value isn't a JsonObject, an
* UnsupportedOperationException is thrown.
*
* @return The JsonObject value of this property
* @throws UnsupportedOperationException If the property's value isn't a JsonObject
*/
public JsonObject getObject() {
return myValue.asObject();
}
/**
* Returns the value of this property if it's a JsonArray. If the value isn't a JsonArray, an
* UnsupportedOperationException is thrown.
*
* @return The JsonArray value of this property
* @throws UnsupportedOperationException If the property's value isn't a JsonArray
*/
public JsonArray getArray() {
return myValue.asArray();
}
/**
* Returns the value of this property.
*
* @return the value of this property, never null
*/
public JsonValue getValue() {
return myValue;
}
@Override
public int hashCode() {
int result = 1;
result = 31 * result + myName.hashCode();
return 31 * result + myValue.hashCode();
}
/**
* Indicates whether a given object is "equal to" this JsonObject. An object is considered equal if it is also a
* JsonObject and both objects contain the same properties in the same order.
*
* If two JsonObjects are equal, they will also produce the same JSON output.
*
*
* @param aObject the object to be compared with this JsonObject
* @return True if the specified object is equal to this JsonObject; else, false
*/
@Override
public boolean equals(final Object aObject) {
final Property jsonObject;
if (this == aObject) {
return true;
}
if (aObject == null || getClass() != aObject.getClass()) {
return false;
}
jsonObject = (Property) aObject;
return myName.equals(jsonObject.myName) && myValue.equals(jsonObject.myValue);
}
}
/**
* A hash code table.
*/
static class HashCodeTable {
/**
* The internal index table.
*/
private final byte[] myIndexTable = new byte[32]; // Must be a power of two
/**
* Creates a new hash code table.
*/
HashCodeTable() {
}
/**
* Creates a new hash code table from the supplied one.
*
* @param aHashCodeTable A hash code table
*/
HashCodeTable(final HashCodeTable aHashCodeTable) {
System.arraycopy(aHashCodeTable.myIndexTable, 0, myIndexTable, 0, myIndexTable.length);
}
/**
* Add a new name to the hash code table.
*
* @param aName A name
* @param aIndex An index position
*/
void add(final String aName, final int aIndex) {
final int slot = hashSlotFor(aName);
if (aIndex < 0xff) {
myIndexTable[slot] = (byte) (aIndex + 1); // Increment by 1
} else {
myIndexTable[slot] = 0; // 0 stands for empty
}
}
/**
* Removes an entry from the hash code table.
*
* @param aIndex The index position of the entry to remove
*/
void remove(final int aIndex) {
for (int index = 0; index < myIndexTable.length; index++) {
if ((myIndexTable[index] & 0xff) == aIndex + 1) {
myIndexTable[index] = 0;
} else if ((myIndexTable[index] & 0xff) > aIndex + 1) {
myIndexTable[index]--;
}
}
}
/**
* Gets the index position of the supplied entry name.
*
* @param aName The entry name for which to get the index position
* @return The index position of the supplied entry name
*/
int get(final Object aName) {
return (myIndexTable[hashSlotFor(aName)] & 0xff) - 1; // Decrement by 1; 0 stands for empty
}
/**
* Gets the hash code table slot for the supplied entry.
*
* @param aEntry An index table entry.
* @return A hash slot
*/
private int hashSlotFor(final Object aEntry) {
return aEntry.hashCode() & myIndexTable.length - 1;
}
}
}
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