/*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
/*
* JSONObject.java
* Copyright (C) 2009 University of Waikato, Hamilton, New Zealand
*/
package weka.core.json;
import java.awt.BorderLayout;
import java.io.Reader;
import java_cup.runtime.DefaultSymbolFactory;
import java_cup.runtime.SymbolFactory;
import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTree;
import javax.swing.tree.DefaultMutableTreeNode;
/**
* Container class for storing a <a href="http://www.json.org/" target="_blank">JSON</a>
* data structure.
*
* @author FracPete (fracpete at waikato dot ac dot nz)
* @version $Revision: 5786 $
*/
public class JSONNode
extends DefaultMutableTreeNode {
/** for serialization. */
private static final long serialVersionUID = -3047440914507883491L;
/**
* The type of a node.
*
* @author FracPete (fracpete at waikato dot ac dot nz)
* @version $Revision: 5786 $
*/
public static enum NodeType {
/** a primitive. */
PRIMITIVE,
/** an object with nested key-value pairs. */
OBJECT,
/** an array. */
ARRAY
}
/** the name of the node. */
protected String m_Name;
/** the value of the node. */
protected Object m_Value;
/** the type of the node. */
protected NodeType m_NodeType;
/**
* Initializes the root container.
*/
public JSONNode() {
this(null, NodeType.OBJECT);
}
/**
* Initializes the primitive container.
*
* @param name the name
* @param value the primitive value
*/
public JSONNode(String name, Boolean value) {
this(name, value, NodeType.PRIMITIVE);
}
/**
* Initializes the primitive container.
*
* @param name the name
* @param value the primitive value
*/
public JSONNode(String name, Integer value) {
this(name, value, NodeType.PRIMITIVE);
}
/**
* Initializes the primitive container.
*
* @param name the name
* @param value the primitive value
*/
public JSONNode(String name, Double value) {
this(name, value, NodeType.PRIMITIVE);
}
/**
* Initializes the primitive container.
*
* @param name the name
* @param value the primitive value
*/
public JSONNode(String name, String value) {
this(name, value, NodeType.PRIMITIVE);
}
/**
* Initializes the object container with null value.
*
* @param name the name
* @param type the node type
*/
protected JSONNode(String name, NodeType type) {
this(name, null, type);
}
/**
* Initializes the container.
*
* @param name the name
* @param value the primitive value
* @param type the type of the node, null for primitives
*/
protected JSONNode(String name, Object value, NodeType type) {
super();
m_Name = name;
m_Value = value;
m_NodeType = type;
}
/**
* Checks whether the node is anonymous.
*
* @return true if no name available
*/
public boolean isAnonymous() {
return (m_Name == null);
}
/**
* Returns the name of the node.
*
* @return the name, null for anonymous nodes
*/
public String getName() {
return m_Name;
}
/**
* Returns the stored value.
*
* @return the stored value, can be null
*/
public Object getValue() {
return getValue(null);
}
/**
* Returns the stored value.
*
* @param defValue the default value, if value is null
* @return the stored value, can be null
*/
public Object getValue(Object defValue) {
if (m_Value == null)
return defValue;
else
return m_Value;
}
/**
* Returns whether the node stores a primitive value or a an array/object.
*
* @return true if a primitive, false in case of an array/object
*/
public boolean isPrimitive() {
return (m_NodeType == NodeType.PRIMITIVE);
}
/**
* Returns wether the node is an array.
*
* @return true if the node is array container
*/
public boolean isArray() {
return (m_NodeType == NodeType.ARRAY);
}
/**
* Returns wether the node is an object.
*
* @return true if the node is object container
*/
public boolean isObject() {
return (m_NodeType == NodeType.OBJECT);
}
/**
* Returns the type of the container.
*
* @return the type
*/
public NodeType getNodeType() {
return m_NodeType;
}
/**
* Adds a "null" child to the object.
*
* @param name the name of the null value
* @return the new node, or null if none added
*/
public JSONNode addNull(String name) {
return add(name, null, NodeType.PRIMITIVE);
}
/**
* Adds a key-value child to the object.
*
* @param name the name of the pair
* @param value the value
* @return the new node, or null if none added
*/
public JSONNode addPrimitive(String name, Boolean value) {
return add(name, value, NodeType.PRIMITIVE);
}
/**
* Adds a key-value child to the object.
*
* @param name the name of the pair
* @param value the value
* @return the new node, or null if none added
*/
public JSONNode addPrimitive(String name, Integer value) {
return add(name, value, NodeType.PRIMITIVE);
}
/**
* Adds a key-value child to the object.
*
* @param name the name of the pair
* @param value the value
* @return the new node, or null if none added
*/
public JSONNode addPrimitive(String name, Double value) {
return add(name, value, NodeType.PRIMITIVE);
}
/**
* Adds a key-value child to the object.
*
* @param name the name of the pair
* @param value the value
* @return the new node, or null if none added
*/
public JSONNode addPrimitive(String name, String value) {
return add(name, value, NodeType.PRIMITIVE);
}
/**
* Adds an array child to the object.
*
* @param name the name of the pair
* @return the new node, or null if none added
*/
public JSONNode addArray(String name) {
return add(name, null, NodeType.ARRAY);
}
/**
* Adds an array element child to the array.
*
* @param value the value of the element array
* @return the new node, or null if none added
*/
public JSONNode addArrayElement(Object value) {
NodeType type;
if (getNodeType() != NodeType.ARRAY)
return null;
type = null;
if (value != null) {
if (value instanceof Boolean)
type = NodeType.PRIMITIVE;
else if (value instanceof Integer)
type = NodeType.PRIMITIVE;
else if (value instanceof Double)
type = NodeType.PRIMITIVE;
else if (value instanceof String)
type = NodeType.PRIMITIVE;
else if (value.getClass().isArray())
type = NodeType.ARRAY;
else
type = NodeType.OBJECT;
}
return add(null, value, type);
}
/**
* Adds an object child to the object.
*
* @param name the name of the pair
* @return the new node, or null if none added
*/
public JSONNode addObject(String name) {
return add(name, null, NodeType.OBJECT);
}
/**
* Adds a key-value child to the object.
*
* @param name the name of the pair
* @param value the value
* @param type the node type, null for primitives
* @return the new node, or null if none added
*/
protected JSONNode add(String name, Object value, NodeType type) {
JSONNode child;
if (isPrimitive())
return null;
child = new JSONNode(name, value, type);
add(child);
return child;
}
/**
* Checks whether the node has a child with the given name.
*
* @param name the name of the child
* @return true if child with that name is available
*/
public boolean hasChild(String name) {
return (getChild(name) != null);
}
/**
* Returns the child with the given name.
*
* @param name the name of the child
* @return the child if available, null otherwise
*/
public JSONNode getChild(String name) {
JSONNode result;
JSONNode node;
int i;
result = null;
for (i = 0; i < getChildCount(); i++) {
node = (JSONNode) getChildAt(i);
if (!node.isAnonymous() && node.getName().equals(name)) {
result = node;
break;
}
}
return result;
}
/**
* Generates the indentation string.
*
* @param level the level
* @return the indentation string (tabs)
*/
protected String getIndentation(int level) {
StringBuffer result;
int i;
result = new StringBuffer();
for (i = 0; i < level; i++)
result.append("\t");
return result.toString();
}
/**
* Escapes ", \, /, \b, \f, \n, \r, \t in strings.
*
* @param o the object to process (only strings get processed)
* @return the processed object
*/
protected Object escape(Object o) {
if (o instanceof String)
return escape((String) o);
else
return o;
}
/**
* Escapes ", /, \b, \f, \n, \r, \t.
*
* @param s the string to process
* @return the processed
*/
protected String escape(String s) {
StringBuffer result;
int i;
char c;
if ( (s.indexOf('\"') > -1)
|| (s.indexOf('\\') > -1)
|| (s.indexOf('\b') > -1)
|| (s.indexOf('\f') > -1)
|| (s.indexOf('\n') > -1)
|| (s.indexOf('\r') > -1)
|| (s.indexOf('\t') > -1) ) {
result = new StringBuffer();
for (i = 0; i < s.length(); i++) {
c = s.charAt(i);
if (c == '\"')
result.append("\\\"");
else if (c == '\\')
result.append("\\\\");
else if (c == '\b')
result.append("\\b");
else if (c == '\f')
result.append("\\f");
else if (c == '\n')
result.append("\\n");
else if (c == '\r')
result.append("\\r");
else if (c == '\t')
result.append("\\t");
else
result.append(c);
}
}
else {
result = new StringBuffer(s);
}
return result.toString();
}
/**
* Dumps the node structure into JSON format.
*
* @param buffer the buffer to add the data to
*/
public void toString(StringBuffer buffer) {
int level;
boolean isLast;
String indent;
int i;
level = getLevel();
isLast = (getNextSibling() == null);
indent = getIndentation(level);
buffer.append(indent);
if (m_Name != null) {
buffer.append("\"");
buffer.append(escape(m_Name));
buffer.append("\" : ");
}
if (isObject()) {
buffer.append("{\n");
for (i = 0; i < getChildCount(); i++)
((JSONNode) getChildAt(i)).toString(buffer);
buffer.append(indent);
buffer.append("}");
}
else if (isArray()) {
buffer.append("[\n");
for (i = 0; i < getChildCount(); i++)
((JSONNode) getChildAt(i)).toString(buffer);
buffer.append(indent);
buffer.append("]");
}
else {
if (m_Value == null) {
buffer.append("null");
}
else if (m_Value instanceof String) {
buffer.append("\"");
buffer.append(escape((String) m_Value));
buffer.append("\"");
}
else {
buffer.append(m_Value.toString());
}
}
if (!isLast)
buffer.append(",");
buffer.append("\n");
}
/**
* Returns a string representation of the node.
*
* @return the string representation
*/
public String toString() {
String result;
result = null;
if (isObject()) {
if (isRoot())
result = "JSON";
else if (m_Name == null)
result = "<object>";
else
result = escape(m_Name) + " (Object)";
}
else if (isArray()) {
if (m_Name == null)
result = "<array>";
else
result = escape(m_Name) + " (Array)";
}
else {
if (m_Name != null)
result = escape(m_Name) + ": " + escape(m_Value);
else
result = "" + m_Value;
}
return result;
}
/**
* Reads the JSON object from the given reader.
*
* @param reader the reader to read the JSON object from
* @return the generated JSON object
* @throws Exception if parsing fails
*/
public static JSONNode read(Reader reader) throws Exception {
SymbolFactory sf;
Parser parser;
sf = new DefaultSymbolFactory();
parser = new Parser(new Scanner(reader, sf), sf);
parser.parse();
return parser.getResult();
}
/**
* Only for testing. Generates a simple JSON object and displays it.
*
* @param args ignored
* @throws Exception if something goes wrong
*/
public static void main(String[] args) throws Exception {
// generates the example listed here:
// http://en.wikipedia.org/wiki/JSON
JSONNode person = new JSONNode();
person.addPrimitive("firstName", "John");
person.addPrimitive("lastName", "Smith");
JSONNode address = person.addObject("address");
address.addPrimitive("streetAddress", "21 2nd Street");
address.addPrimitive("city", "New York");
address.addPrimitive("state", "NY");
address.addPrimitive("postalCode", 10021);
JSONNode phonenumbers = person.addArray("phoneNumbers");
phonenumbers.addArrayElement("212 555-1234");
phonenumbers.addArrayElement("646 555-4567");
// output in console
StringBuffer buffer = new StringBuffer();
person.toString(buffer);
System.out.println(buffer.toString());
// display GUI
JTree tree = new JTree(person);
JFrame frame = new JFrame("JSON");
frame.setSize(800, 600);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().setLayout(new BorderLayout());
frame.getContentPane().add(new JScrollPane(tree), BorderLayout.CENTER);
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
}