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/*******************************************************************************
* Copyright (c) 2013, 2015 EclipseSource.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all
* copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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package org.cohesive.envoy.json;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.Reader;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;
import org.cohesive.envoy.json.JsonObject.Member;
/**
* Represents a JSON object, a set of name/value pairs, where the names are strings and the values
* are JSON values.
*
* Members 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 members. On the other
* hand, the add methods do not prevent adding multiple members with the same name.
* Duplicate names are discouraged but not prohibited by JSON.
*
*
* Members 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 members in
* document order using an {@link #iterator()} or an enhanced for loop:
*
*
* for (Member member : jsonObject) {
* String name = member.getName();
* JsonValue value = member.getValue();
* ...
* }
*
*
* Even though JSON objects are unordered by definition, instances of this class preserve the order
* of members 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.
*
*/
@SuppressWarnings("serial") // use default serial UID
public class JsonObject extends JsonValue implements Iterable {
private final List names;
private final List values;
private transient HashIndexTable table;
/**
* Creates a new empty JsonObject.
*/
public JsonObject() {
names = new ArrayList();
values = new ArrayList();
table = new HashIndexTable();
}
/**
* Creates a new JsonObject, initialized with the contents of the specified JSON object.
*
* @param object
* the JSON object to get the initial contents from, must not be null
*/
public JsonObject(JsonObject object) {
this(object, false);
}
private JsonObject(JsonObject object, boolean unmodifiable) {
if (object == null) {
throw new NullPointerException("object is null");
}
if (unmodifiable) {
names = Collections.unmodifiableList(object.names);
values = Collections.unmodifiableList(object.values);
} else {
names = new ArrayList(object.names);
values = new ArrayList(object.values);
}
table = new HashIndexTable();
updateHashIndex();
}
/**
* Reads a JSON object from the given reader.
*
* Characters are read in chunks and buffered internally, therefore wrapping an existing reader in
* an additional BufferedReader does not improve reading
* performance.
*
*
* @param reader
* the reader to read the JSON object from
* @return the JSON object that has been read
* @throws IOException
* if an I/O error occurs in the reader
* @throws ParseException
* if the input is not valid JSON
* @throws UnsupportedOperationException
* if the input does not contain a JSON object
* @deprecated Use {@link Json#parse(Reader)}{@link JsonValue#asObject() .asObject()} instead
*/
@Deprecated
public static JsonObject readFrom(Reader reader) throws IOException {
return JsonValue.readFrom(reader).asObject();
}
/**
* Reads a JSON object from the given string.
*
* @param string
* the string that contains the JSON object
* @return the JSON object that has been read
* @throws ParseException
* if the input is not valid JSON
* @throws UnsupportedOperationException
* if the input does not contain a JSON object
* @deprecated Use {@link Json#parse(String)}{@link JsonValue#asObject() .asObject()} instead
*/
@Deprecated
public static JsonObject readFrom(String string) {
return JsonValue.readFrom(string).asObject();
}
/**
* Returns an unmodifiable JsonObject for the specified one. This method allows to provide
* 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 object
* the JsonObject for which an unmodifiable JsonObject is to be returned
* @return an unmodifiable view of the specified JsonObject
*/
public static JsonObject unmodifiableObject(JsonObject object) {
return new JsonObject(object, true);
}
/**
* Appends a new member 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 member with the same name. In order to
* replace existing members, use the method set(name, value) instead. However,
* add is much faster than set (because it does not need to
* search for existing members). Therefore add should be preferred when constructing new
* objects.
*
*
* @param name
* the name of the member to add
* @param value
* the value of the member to add
* @return the object itself, to enable method chaining
*/
public JsonObject add(String name, int value) {
add(name, Json.value(value));
return this;
}
/**
* Appends a new member 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 member with the same name. In order to
* replace existing members, use the method set(name, value) instead. However,
* add is much faster than set (because it does not need to
* search for existing members). Therefore add should be preferred when constructing new
* objects.
*
*
* @param name
* the name of the member to add
* @param value
* the value of the member to add
* @return the object itself, to enable method chaining
*/
public JsonObject add(String name, long value) {
add(name, Json.value(value));
return this;
}
/**
* Appends a new member 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 member with the same name. In order to
* replace existing members, use the method set(name, value) instead. However,
* add is much faster than set (because it does not need to
* search for existing members). Therefore add should be preferred when constructing new
* objects.
*
*
* @param name
* the name of the member to add
* @param value
* the value of the member to add
* @return the object itself, to enable method chaining
*/
public JsonObject add(String name, float value) {
add(name, Json.value(value));
return this;
}
/**
* Appends a new member 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 member with the same name. In order to
* replace existing members, use the method set(name, value) instead. However,
* add is much faster than set (because it does not need to
* search for existing members). Therefore add should be preferred when constructing new
* objects.
*
*
* @param name
* the name of the member to add
* @param value
* the value of the member to add
* @return the object itself, to enable method chaining
*/
public JsonObject add(String name, double value) {
add(name, Json.value(value));
return this;
}
/**
* Appends a new member 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 member with the same name. In order to
* replace existing members, use the method set(name, value) instead. However,
* add is much faster than set (because it does not need to
* search for existing members). Therefore add should be preferred when constructing new
* objects.
*
*
* @param name
* the name of the member to add
* @param value
* the value of the member to add
* @return the object itself, to enable method chaining
*/
public JsonObject add(String name, boolean value) {
add(name, Json.value(value));
return this;
}
/**
* Appends a new member 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 member with the same name. In order to
* replace existing members, use the method set(name, value) instead. However,
* add is much faster than set (because it does not need to
* search for existing members). Therefore add should be preferred when constructing new
* objects.
*
*
* @param name
* the name of the member to add
* @param value
* the value of the member to add
* @return the object itself, to enable method chaining
*/
public JsonObject add(String name, String value) {
add(name, Json.value(value));
return this;
}
/**
* Appends a new member 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 member with the same name. In order to
* replace existing members, use the method set(name, value) instead. However,
* add is much faster than set (because it does not need to
* search for existing members). Therefore add should be preferred when constructing new
* objects.
*
*
* @param name
* the name of the member to add
* @param value
* the value of the member to add, must not be null
* @return the object itself, to enable method chaining
*/
public JsonObject add(String name, JsonValue value) {
if (name == null) {
throw new NullPointerException("name is null");
}
if (value == null) {
throw new NullPointerException("value is null");
}
table.add(name, names.size());
names.add(name);
values.add(value);
return this;
}
/**
* Sets the value of the member with the specified name to the JSON representation of the
* specified int value. If this object does not contain a member with this name, a
* new member is added at the end of the object. If this object contains multiple members 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 members, the method add(name, value) should be preferred which is much
* faster (as it does not need to search for existing members).
*
*
* @param name
* the name of the member to replace
* @param value
* the value to set to the member
* @return the object itself, to enable method chaining
*/
public JsonObject set(String name, int value) {
set(name, Json.value(value));
return this;
}
/**
* Sets the value of the member with the specified name to the JSON representation of the
* specified long value. If this object does not contain a member with this name, a
* new member is added at the end of the object. If this object contains multiple members 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 members, the method add(name, value) should be preferred which is much
* faster (as it does not need to search for existing members).
*
*
* @param name
* the name of the member to replace
* @param value
* the value to set to the member
* @return the object itself, to enable method chaining
*/
public JsonObject set(String name, long value) {
set(name, Json.value(value));
return this;
}
/**
* Sets the value of the member with the specified name to the JSON representation of the
* specified float value. If this object does not contain a member with this name, a
* new member is added at the end of the object. If this object contains multiple members 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 members, the method add(name, value) should be preferred which is much
* faster (as it does not need to search for existing members).
*
*
* @param name
* the name of the member to add
* @param value
* the value of the member to add
* @return the object itself, to enable method chaining
*/
public JsonObject set(String name, float value) {
set(name, Json.value(value));
return this;
}
/**
* Sets the value of the member with the specified name to the JSON representation of the
* specified double value. If this object does not contain a member with this name, a
* new member is added at the end of the object. If this object contains multiple members 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 members, the method add(name, value) should be preferred which is much
* faster (as it does not need to search for existing members).
*
*
* @param name
* the name of the member to add
* @param value
* the value of the member to add
* @return the object itself, to enable method chaining
*/
public JsonObject set(String name, double value) {
set(name, Json.value(value));
return this;
}
/**
* Sets the value of the member with the specified name to the JSON representation of the
* specified boolean value. If this object does not contain a member with this name,
* a new member is added at the end of the object. If this object contains multiple members 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 members, the method add(name, value) should be preferred which is much
* faster (as it does not need to search for existing members).
*
*
* @param name
* the name of the member to add
* @param value
* the value of the member to add
* @return the object itself, to enable method chaining
*/
public JsonObject set(String name, boolean value) {
set(name, Json.value(value));
return this;
}
/**
* Sets the value of the member with the specified name to the JSON representation of the
* specified string. If this object does not contain a member with this name, a new member is
* added at the end of the object. If this object contains multiple members 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 members, the method add(name, value) should be preferred which is much
* faster (as it does not need to search for existing members).
*
*
* @param name
* the name of the member to add
* @param value
* the value of the member to add
* @return the object itself, to enable method chaining
*/
public JsonObject set(String name, String value) {
set(name, Json.value(value));
return this;
}
/**
* Sets the value of the member with the specified name to the specified JSON value. If this
* object does not contain a member with this name, a new member is added at the end of the
* object. If this object contains multiple members 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 members, the method add(name, value) should be preferred which is much
* faster (as it does not need to search for existing members).
*
*
* @param name
* the name of the member to add
* @param value
* the value of the member to add, must not be null
* @return the object itself, to enable method chaining
*/
public JsonObject set(String name, JsonValue value) {
if (name == null) {
throw new NullPointerException("name is null");
}
if (value == null) {
throw new NullPointerException("value is null");
}
int index = indexOf(name);
if (index != -1) {
values.set(index, value);
} else {
table.add(name, names.size());
names.add(name);
values.add(value);
}
return this;
}
/**
* Removes a member with the specified name from this object. If this object contains multiple
* members with the given name, only the last one is removed. If this object does not contain a
* member with the specified name, the object is not modified.
*
* @param name
* the name of the member to remove
* @return the object itself, to enable method chaining
*/
public JsonObject remove(String name) {
if (name == null) {
throw new NullPointerException("name is null");
}
int index = indexOf(name);
if (index != -1) {
table.remove(index);
names.remove(index);
values.remove(index);
}
return this;
}
/**
* Checks if a specified member 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 name
* the name of the member to check for
* @return whether or not the member is present
*/
public boolean contains(String name) {
return names.contains(name);
}
/**
* Copies all members of the specified object into this object. When the specified object contains
* members 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 object
* the object to merge
* @return the object itself, to enable method chaining
*/
public JsonObject merge(JsonObject object) {
if (object == null) {
throw new NullPointerException("object is null");
}
for (Member member : object) {
this.set(member.name, member.value);
}
return this;
}
/**
* Returns the value of the member with the specified name in this object. If this object contains
* multiple members with the given name, this method will return the last one.
*
* @param name
* the name of the member whose value is to be returned
* @return the value of the last member with the specified name, or null if this
* object does not contain a member with that name
*/
public JsonValue get(String name) {
if (name == null) {
throw new NullPointerException("name is null");
}
int index = indexOf(name);
return index != -1 ? values.get(index) : null;
}
/**
* Returns the int value of the member with the specified name in this object. If
* this object does not contain a member with this name, the given default value is returned. If
* this object contains multiple members with the given name, the last one will be picked. If this
* member's value does not represent a JSON number or if it cannot be interpreted as Java
* int, an exception is thrown.
*
* @param name
* the name of the member whose value is to be returned
* @param defaultValue
* the value to be returned if the requested member is missing
* @return the value of the last member with the specified name, or the given default value if
* this object does not contain a member with that name
*/
public int getInt(String name, int defaultValue) {
JsonValue value = get(name);
return value != null ? value.asInt() : defaultValue;
}
/**
* Returns the long value of the member with the specified name in this object. If
* this object does not contain a member with this name, the given default value is returned. If
* this object contains multiple members with the given name, the last one will be picked. If this
* member's value does not represent a JSON number or if it cannot be interpreted as Java
* long, an exception is thrown.
*
* @param name
* the name of the member whose value is to be returned
* @param defaultValue
* the value to be returned if the requested member is missing
* @return the value of the last member with the specified name, or the given default value if
* this object does not contain a member with that name
*/
public long getLong(String name, long defaultValue) {
JsonValue value = get(name);
return value != null ? value.asLong() : defaultValue;
}
/**
* Returns the float value of the member with the specified name in this object. If
* this object does not contain a member with this name, the given default value is returned. If
* this object contains multiple members with the given name, the last one will be picked. If this
* member's value does not represent a JSON number or if it cannot be interpreted as Java
* float, an exception is thrown.
*
* @param name
* the name of the member whose value is to be returned
* @param defaultValue
* the value to be returned if the requested member is missing
* @return the value of the last member with the specified name, or the given default value if
* this object does not contain a member with that name
*/
public float getFloat(String name, float defaultValue) {
JsonValue value = get(name);
return value != null ? value.asFloat() : defaultValue;
}
/**
* Returns the double value of the member with the specified name in this object. If
* this object does not contain a member with this name, the given default value is returned. If
* this object contains multiple members with the given name, the last one will be picked. If this
* member's value does not represent a JSON number or if it cannot be interpreted as Java
* double, an exception is thrown.
*
* @param name
* the name of the member whose value is to be returned
* @param defaultValue
* the value to be returned if the requested member is missing
* @return the value of the last member with the specified name, or the given default value if
* this object does not contain a member with that name
*/
public double getDouble(String name, double defaultValue) {
JsonValue value = get(name);
return value != null ? value.asDouble() : defaultValue;
}
/**
* Returns the boolean value of the member with the specified name in this object. If
* this object does not contain a member with this name, the given default value is returned. If
* this object contains multiple members with the given name, the last one will be picked. If this
* member's value does not represent a JSON true or false value, an
* exception is thrown.
*
* @param name
* the name of the member whose value is to be returned
* @param defaultValue
* the value to be returned if the requested member is missing
* @return the value of the last member with the specified name, or the given default value if
* this object does not contain a member with that name
*/
public boolean getBoolean(String name, boolean defaultValue) {
JsonValue value = get(name);
return value != null ? value.asBoolean() : defaultValue;
}
/**
* Returns the String value of the member with the specified name in this object. If
* this object does not contain a member with this name, the given default value is returned. If
* this object contains multiple members with the given name, the last one is picked. If this
* member's value does not represent a JSON string, an exception is thrown.
*
* @param name
* the name of the member whose value is to be returned
* @param defaultValue
* the value to be returned if the requested member is missing
* @return the value of the last member with the specified name, or the given default value if
* this object does not contain a member with that name
*/
public String getString(String name, String defaultValue) {
JsonValue value = get(name);
return value != null ? value.asString() : defaultValue;
}
/**
* Returns the number of members (name/value pairs) in this object.
*
* @return the number of members in this object
*/
public int size() {
return names.size();
}
/**
* Returns true if this object contains no members.
*
* @return true if this object contains no members
*/
public boolean isEmpty() {
return names.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(names);
}
/**
* Returns an iterator over the members of this object in document order. The returned iterator
* cannot be used to modify this object.
*
* @return an iterator over the members of this object
*/
public Iterator iterator() {
final Iterator namesIterator = names.iterator();
final Iterator valuesIterator = values.iterator();
return new Iterator() {
public boolean hasNext() {
return namesIterator.hasNext();
}
public Member next() {
String name = namesIterator.next();
JsonValue value = valuesIterator.next();
return new Member(name, value);
}
public void remove() {
throw new UnsupportedOperationException();
}
};
}
@Override
void write(JsonWriter writer) throws IOException {
writer.writeObjectOpen();
Iterator namesIterator = names.iterator();
Iterator valuesIterator = values.iterator();
if (namesIterator.hasNext()) {
writer.writeMemberName(namesIterator.next());
writer.writeMemberSeparator();
valuesIterator.next().write(writer);
while (namesIterator.hasNext()) {
writer.writeObjectSeparator();
writer.writeMemberName(namesIterator.next());
writer.writeMemberSeparator();
valuesIterator.next().write(writer);
}
}
writer.writeObjectClose();
}
@Override
public boolean isObject() {
return true;
}
@Override
public JsonObject asObject() {
return this;
}
@Override
public int hashCode() {
int result = 1;
result = 31 * result + names.hashCode();
result = 31 * result + values.hashCode();
return result;
}
@Override
public boolean equals(Object obj) {
if (this == obj) {
return true;
}
if (obj == null) {
return false;
}
if (getClass() != obj.getClass()) {
return false;
}
JsonObject other = (JsonObject)obj;
return names.equals(other.names) && values.equals(other.values);
}
int indexOf(String name) {
int index = table.get(name);
if (index != -1 && name.equals(names.get(index))) {
return index;
}
return names.lastIndexOf(name);
}
private synchronized void readObject(ObjectInputStream inputStream)
throws IOException, ClassNotFoundException
{
inputStream.defaultReadObject();
table = new HashIndexTable();
updateHashIndex();
}
private void updateHashIndex() {
int size = names.size();
for (int i = 0; i < size; i++) {
table.add(names.get(i), i);
}
}
/**
* Represents a member of a JSON object, a pair of a name and a value.
*/
public static class Member {
private final String name;
private final JsonValue value;
Member(String name, JsonValue value) {
this.name = name;
this.value = value;
}
/**
* Returns the name of this member.
*
* @return the name of this member, never null
*/
public String getName() {
return name;
}
/**
* Returns the value of this member.
*
* @return the value of this member, never null
*/
public JsonValue getValue() {
return value;
}
@Override
public int hashCode() {
int result = 1;
result = 31 * result + name.hashCode();
result = 31 * result + value.hashCode();
return result;
}
/**
* 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 members in
* the same order.
*
* If two JsonObjects are equal, they will also produce the same JSON output.
*
*
* @param object
* the object to be compared with this JsonObject
* @return true if the specified object is equal to this JsonObject, false
* otherwise
*/
@Override
public boolean equals(Object object) {
if (this == object) {
return true;
}
if (object == null) {
return false;
}
if (getClass() != object.getClass()) {
return false;
}
Member other = (Member)object;
return name.equals(other.name) && value.equals(other.value);
}
}
static class HashIndexTable {
private final byte[] hashTable = new byte[32]; // must be a power of two
HashIndexTable() {
}
HashIndexTable(HashIndexTable original) {
System.arraycopy(original.hashTable, 0, hashTable, 0, hashTable.length);
}
void add(String name, int index) {
int slot = hashSlotFor(name);
if (index < 0xff) {
// increment by 1, 0 stands for empty
hashTable[slot] = (byte)(index + 1);
} else {
hashTable[slot] = 0;
}
}
void remove(int index) {
for (int i = 0; i < hashTable.length; i++) {
if ((hashTable[i] & 0xff) == index + 1) {
hashTable[i] = 0;
} else if ((hashTable[i] & 0xff) > index + 1) {
hashTable[i]--;
}
}
}
int get(Object name) {
int slot = hashSlotFor(name);
// subtract 1, 0 stands for empty
return (hashTable[slot] & 0xff) - 1;
}
private int hashSlotFor(Object element) {
return element.hashCode() & hashTable.length - 1;
}
}
}