blob: 30a790dad68c96705f1955c3bf45bec20c316f23 [file] [log] [blame]
package org.apache.tapestry.json;
/*
Copyright (c) 2002 JSON.org
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 shall be used for Good, not Evil.
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
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
*/
import java.text.ParseException;
import java.util.ArrayList;
import java.util.Collection;
import java.util.NoSuchElementException;
/**
* A JSONArray is an ordered sequence of values. Its external form is a string
* wrapped in square brackets with commas between the values. The internal form
* is an object having get() and opt() methods for accessing the values by
* index, and put() methods for adding or replacing values. The values can be
* any of these types: Boolean, JSONArray, JSONObject, Number, String, or the
* JSONObject.NULL object.
* <p>
* The constructor can convert a JSON external form string into an internal form
* Java object. The toString() method creates an external form string.
* <p>
* A get() method returns a value if one can be found, and throws an exception
* if one cannot be found. An opt() method returns a default value instead of
* throwing an exception, and so is useful for obtaining optional values.
* <p>
* The generic get() and opt() methods return an object which you can cast or
* query for type. There are also typed get() and opt() methods that do typing
* checking and type coersion for you.
* <p>
* The texts produced by the toString() methods are very strict. The
* constructors are more forgiving in the texts they will accept.
* <ul>
* <li>An extra <code>,</code>&nbsp;<small>(comma)</small> may appear just
* before the closing bracket.</li>
* <li>The null value will be inserted when there is <code>,</code>&nbsp;<small>(comma)</small>
* elision.</li>
* <li>Strings may be quoted with <code>'</code>&nbsp;<small>(single quote)</small>.</li>
* <li>Strings do not need to be quoted at all if they do not begin with a
* quote or single quote, and if they do not contain leading or trailing spaces,
* and if they do not contain any of these characters:
* <code>{ } [ ] / \ : , = ; #</code> and if they do not look like numbers and
* if they are not the reserved words <code>true</code>, <code>false</code>,
* or <code>null</code>.</li>
* <li>Values can be followed by <code>;</code> as well as by <code>,</code></li>
* <li>Numbers may have the <code>0-</code> <small>(octal)</small> or
* <code>0x-</code> <small>(hex)</small> prefix.</li>
* <li>Line comments can begin with <code>#</code></li>
* </ul>
*
* @author JSON.org
* @version 1
*/
public class JSONArray
{
/**
* The getArrayList where the JSONArray's properties are kept.
*/
private ArrayList myArrayList;
/**
* Construct an empty JSONArray.
*/
public JSONArray()
{
this.myArrayList = new ArrayList();
}
/**
* Construct a JSONArray from a JSONTokener.
*
* @param x
* A JSONTokener
* @exception ParseException
* A JSONArray must start with '['
* @exception ParseException
* Expected a ',' or ']'
*/
public JSONArray(JSONTokener x)
throws ParseException
{
this();
if (x.nextClean() != '[') { throw x
.syntaxError("A JSONArray must start with '['"); }
if (x.nextClean() == ']') { return; }
x.back();
while(true)
{
if (x.nextClean() == ',')
{
x.back();
this.myArrayList.add(null);
}
else
{
x.back();
this.myArrayList.add(x.nextValue());
}
switch(x.nextClean())
{
case ';':
case ',':
if (x.nextClean() == ']') { return; }
x.back();
break;
case ']':
return;
default:
throw x.syntaxError("Expected a ',' or ']'");
}
}
}
/**
* Construct a JSONArray from a source string.
*
* @param string
* A string that begins with <code>[</code>&nbsp;<small>(left
* bracket)</small> and ends with <code>]</code>&nbsp;<small>(right
* bracket)</small>.
* @exception ParseException
* The string must conform to JSON syntax.
*/
public JSONArray(String string)
throws ParseException
{
this(new JSONTokener(string));
}
/**
* Construct a JSONArray from a Collection.
*
* @param collection
* A Collection.
*/
public JSONArray(Collection collection)
{
this.myArrayList = new ArrayList(collection);
}
/**
* Get the object value associated with an index.
*
* @param index
* The index must be between 0 and length() - 1.
* @return An object value.
* @exception NoSuchElementException
*/
public Object get(int index)
{
Object o = opt(index);
if (o == null) { throw new NoSuchElementException("JSONArray[" + index
+ "] not found."); }
return o;
}
/**
* Get the ArrayList which is holding the elements of the JSONArray.
*
* @return The ArrayList.
*/
ArrayList getArrayList()
{
return this.myArrayList;
}
/**
* Get the boolean value associated with an index. The string values "true"
* and "false" are converted to boolean.
*
* @param index
* The index must be between 0 and length() - 1.
* @return The truth.
* @exception NoSuchElementException
* if the index is not found
* @exception ClassCastException
*/
public boolean getBoolean(int index)
{
Object o = get(index);
if (o.equals(Boolean.FALSE)
|| (o instanceof String && ((String) o)
.equalsIgnoreCase("false")))
{
return false;
}
else if (o.equals(Boolean.TRUE)
|| (o instanceof String && ((String) o)
.equalsIgnoreCase("true"))) { return true; }
throw new ClassCastException("JSONArray[" + index + "] not a Boolean.");
}
/**
* Get the double value associated with an index.
*
* @param index
* The index must be between 0 and length() - 1.
* @return The value.
* @exception NoSuchElementException
* if the key is not found
* @exception NumberFormatException
* if the value cannot be converted to a number.
*/
public double getDouble(int index)
{
Object o = get(index);
if (o instanceof Number) { return ((Number) o).doubleValue(); }
if (o instanceof String) { return new Double((String) o).doubleValue(); }
throw new NumberFormatException("JSONObject[" + index
+ "] is not a number.");
}
/**
* Get the int value associated with an index.
*
* @param index
* The index must be between 0 and length() - 1.
* @return The value.
* @exception NoSuchElementException
* if the key is not found
* @exception NumberFormatException
* if the value cannot be converted to a number.
*/
public int getInt(int index)
{
Object o = get(index);
return o instanceof Number ? ((Number) o).intValue()
: (int) getDouble(index);
}
/**
* Get the JSONArray associated with an index.
*
* @param index
* The index must be between 0 and length() - 1.
* @return A JSONArray value.
* @exception NoSuchElementException
* if the index is not found or if the value is not a
* JSONArray
*/
public JSONArray getJSONArray(int index)
{
Object o = get(index);
if (o instanceof JSONArray) { return (JSONArray) o; }
throw new NoSuchElementException("JSONArray[" + index
+ "] is not a JSONArray.");
}
/**
* Get the JSONObject associated with an index.
*
* @param index
* subscript
* @return A JSONObject value.
* @exception NoSuchElementException
* if the index is not found or if the value is not a
* JSONObject
*/
public JSONObject getJSONObject(int index)
{
Object o = get(index);
if (o instanceof JSONObject) { return (JSONObject) o; }
throw new NoSuchElementException("JSONArray[" + index
+ "] is not a JSONObject.");
}
/**
* Get the string associated with an index.
*
* @param index
* The index must be between 0 and length() - 1.
* @return A string value.
* @exception NoSuchElementException
*/
public String getString(int index)
{
return get(index).toString();
}
/**
* Determine if the value is null.
*
* @param index
* The index must be between 0 and length() - 1.
* @return true if the value at the index is null, or if there is no value.
*/
public boolean isNull(int index)
{
Object o = opt(index);
return o == null || o.equals(null);
}
/**
* Make a string from the contents of this JSONArray. The separator string
* is inserted between each element. Warning: This method assumes that the
* data structure is acyclical.
*
* @param separator
* A string that will be inserted between the elements.
* @return a string.
*/
public String join(String separator)
{
int len = length();
StringBuffer sb = new StringBuffer();
for(int i = 0; i < len; i += 1)
{
if (i > 0)
{
sb.append(separator);
}
sb.append(JSONObject.valueToString(this.myArrayList.get(i)));
}
return sb.toString();
}
/**
* Get the length of the JSONArray.
*
* @return The length (or size).
*/
public int length()
{
return this.myArrayList.size();
}
/**
* Get the optional object value associated with an index.
*
* @param index
* The index must be between 0 and length() - 1.
* @return An object value, or null if there is no object at that index.
*/
public Object opt(int index)
{
return index < 0 || index >= length() ? null : this.myArrayList
.get(index);
}
/**
* Get the optional boolean value associated with an index. It returns false
* if there is no value at that index, or if the value is not Boolean.TRUE
* or the String "true".
*
* @param index
* The index must be between 0 and length() - 1.
* @return The truth.
*/
public boolean optBoolean(int index)
{
return optBoolean(index, false);
}
/**
* Get the optional boolean value associated with an index. It returns the
* defaultValue if there is no value at that index or if it is not a Boolean
* or the String "true" or "false" (case insensitive).
*
* @param index
* The index must be between 0 and length() - 1.
* @param defaultValue
* A boolean default.
* @return The truth.
*/
public boolean optBoolean(int index, boolean defaultValue)
{
Object o = opt(index);
if (o != null)
{
if (o.equals(Boolean.FALSE)
|| (o instanceof String && ((String) o)
.equalsIgnoreCase("false")))
{
return false;
}
else if (o.equals(Boolean.TRUE)
|| (o instanceof String && ((String) o)
.equalsIgnoreCase("true"))) { return true; }
}
return defaultValue;
}
/**
* Get the optional double value associated with an index. NaN is returned
* if the index is not found, or if the value is not a number and cannot be
* converted to a number.
*
* @param index
* The index must be between 0 and length() - 1.
* @return The value.
*/
public double optDouble(int index)
{
return optDouble(index, Double.NaN);
}
/**
* Get the optional double value associated with an index. The defaultValue
* is returned if the index is not found, or if the value is not a number
* and cannot be converted to a number.
*
* @param index
* subscript
* @param defaultValue
* The default value.
* @return The value.
*/
public double optDouble(int index, double defaultValue)
{
Object o = opt(index);
if (o != null)
{
if (o instanceof Number) { return ((Number) o).doubleValue(); }
try
{
return new Double((String) o).doubleValue();
}
catch (Exception e)
{
return defaultValue;
}
}
return defaultValue;
}
/**
* Get the optional int value associated with an index. Zero is returned if
* the index is not found, or if the value is not a number and cannot be
* converted to a number.
*
* @param index
* The index must be between 0 and length() - 1.
* @return The value.
*/
public int optInt(int index)
{
return optInt(index, 0);
}
/**
* Get the optional int value associated with an index. The defaultValue is
* returned if the index is not found, or if the value is not a number and
* cannot be converted to a number.
*
* @param index
* The index must be between 0 and length() - 1.
* @param defaultValue
* The default value.
* @return The value.
*/
public int optInt(int index, int defaultValue)
{
Object o = opt(index);
if (o != null)
{
if (o instanceof Number) { return ((Number) o).intValue(); }
try
{
return Integer.parseInt((String) o);
}
catch (Exception e)
{
return defaultValue;
}
}
return defaultValue;
}
/**
* Get the optional JSONArray associated with an index.
*
* @param index
* subscript
* @return A JSONArray value, or null if the index has no value, or if the
* value is not a JSONArray.
*/
public JSONArray optJSONArray(int index)
{
Object o = opt(index);
return o instanceof JSONArray ? (JSONArray) o : null;
}
/**
* Get the optional JSONObject associated with an index. Null is returned if
* the key is not found, or null if the index has no value, or if the value
* is not a JSONObject.
*
* @param index
* The index must be between 0 and length() - 1.
* @return A JSONObject value.
*/
public JSONObject optJSONObject(int index)
{
Object o = opt(index);
return o instanceof JSONObject ? (JSONObject) o : null;
}
/**
* Get the optional string value associated with an index. It returns an
* empty string if there is no value at that index. If the value is not a
* string and is not null, then it is coverted to a string.
*
* @param index
* The index must be between 0 and length() - 1.
* @return A String value.
*/
public String optString(int index)
{
return optString(index, "");
}
/**
* Get the optional string associated with an index. The defaultValue is
* returned if the key is not found.
*
* @param index
* The index must be between 0 and length() - 1.
* @param defaultValue
* The default value.
* @return A String value.
*/
public String optString(int index, String defaultValue)
{
Object o = opt(index);
return o != null ? o.toString() : defaultValue;
}
/**
* Append a boolean value.
*
* @param value
* A boolean value.
* @return this.
*/
public JSONArray put(boolean value)
{
put(Boolean.valueOf(value));
return this;
}
/**
* Append a double value.
*
* @param value
* A double value.
* @return this.
*/
public JSONArray put(double value)
{
put(new Double(value));
return this;
}
/**
* Append an int value.
*
* @param value
* An int value.
* @return this.
*/
public JSONArray put(int value)
{
put(new Integer(value));
return this;
}
/**
* Append an object value.
*
* @param value
* An object value. The value should be a Boolean, Double,
* Integer, JSONArray, JSObject, or String, or the
* JSONObject.NULL object.
* @return this.
*/
public JSONArray put(Object value)
{
this.myArrayList.add(value);
return this;
}
/**
* Put or replace a boolean value in the JSONArray.
*
* @param index
* subscript The subscript. If the index is greater than the
* length of the JSONArray, then null elements will be added as
* necessary to pad it out.
* @param value
* A boolean value.
* @return this.
* @exception NoSuchElementException
* The index must not be negative.
*/
public JSONArray put(int index, boolean value)
{
put(index, Boolean.valueOf(value));
return this;
}
/**
* Put or replace a double value.
*
* @param index
* subscript The subscript. If the index is greater than the
* length of the JSONArray, then null elements will be added as
* necessary to pad it out.
* @param value
* A double value.
* @return this.
* @exception NoSuchElementException
* The index must not be negative.
*/
public JSONArray put(int index, double value)
{
put(index, new Double(value));
return this;
}
/**
* Put or replace an int value.
*
* @param index
* subscript The subscript. If the index is greater than the
* length of the JSONArray, then null elements will be added as
* necessary to pad it out.
* @param value
* An int value.
* @return this.
* @exception NoSuchElementException
* The index must not be negative.
*/
public JSONArray put(int index, int value)
{
put(index, new Integer(value));
return this;
}
/**
* Put or replace an object value in the JSONArray.
*
* @param index
* The subscript. If the index is greater than the length of the
* JSONArray, then null elements will be added as necessary to
* pad it out.
* @param value
* An object value.
* @return this.
* @exception NoSuchElementException
* The index must not be negative.
* @exception NullPointerException
* The index must not be null.
*/
public JSONArray put(int index, Object value)
{
if (index < 0)
{
throw new NoSuchElementException("JSONArray[" + index
+ "] not found.");
}
else if (value == null)
{
throw new NullPointerException();
}
else if (index < length())
{
this.myArrayList.set(index, value);
}
else
{
while(index != length())
{
put(null);
}
put(value);
}
return this;
}
/**
* Produce a JSONObject by combining a JSONArray of names with the values of
* this JSONArray.
*
* @param names
* A JSONArray containing a list of key strings. These will be
* paired with the values.
* @return A JSONObject, or null if there are no names or if this JSONArray
* has no values.
*/
public JSONObject toJSONObject(JSONArray names)
{
if (names == null || names.length() == 0 || length() == 0) { return null; }
JSONObject jo = new JSONObject();
for(int i = 0; i < names.length(); i += 1)
{
jo.put(names.getString(i), this.opt(i));
}
return jo;
}
/**
* Make an JSON external form string of this JSONArray. For compactness, no
* unnecessary whitespace is added. Warning: This method assumes that the
* data structure is acyclical.
*
* @return a printable, displayable, transmittable representation of the
* array.
*/
public String toString()
{
return '[' + join(",") + ']';
}
/**
* Make a prettyprinted JSON string of this JSONArray. Warning: This method
* assumes that the data structure is non-cyclical.
*
* @param indentFactor
* The number of spaces to add to each level of indentation.
* @return a printable, displayable, transmittable representation of the
* object, beginning with <code>[</code>&nbsp;<small>(left
* bracket)</small> and ending with <code>]</code>&nbsp;<small>(right
* bracket)</small>.
*/
public String toString(int indentFactor)
{
return toString(indentFactor, 0);
}
/**
* Make a prettyprinted string of this JSONArray. Warning: This method
* assumes that the data structure is non-cyclical.
*
* @param indentFactor
* The number of spaces to add to each level of indentation.
* @param indent
* The indention of the top level.
* @return a printable, displayable, transmittable representation of the
* array.
*/
String toString(int indentFactor, int indent)
{
int len = length();
if (len == 0) { return "[]"; }
int i;
StringBuffer sb = new StringBuffer("[");
if (len == 1)
{
sb.append(JSONObject.valueToString(this.myArrayList.get(0),
indentFactor, indent));
}
else
{
int newindent = indent + indentFactor;
sb.append('\n');
for(i = 0; i < len; i += 1)
{
if (i > 0)
{
sb.append(",\n");
}
for(int j = 0; j < newindent; j += 1)
{
sb.append(' ');
}
sb.append(JSONObject.valueToString(this.myArrayList.get(i),
indentFactor, newindent));
}
sb.append('\n');
for(i = 0; i < indent; i += 1)
{
sb.append(' ');
}
}
sb.append(']');
return sb.toString();
}
}