Package processing.data

Class JSONArray

java.lang.Object
processing.data.JSONArray
public class JSONArray extends Object
A JSONArray stores an array of JSON objects. JSONArrays can be generated from scratch, dynamically, or using data from an existing file. JSON can also be output and saved to disk, as in the example above.

Advanced

A JSONArray is an ordered sequence of values. Its external text form is a string wrapped in square brackets with commas separating 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.

The constructor can convert a JSON text into a Java object. The toString method converts to JSON text.

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.

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 type checking and type coercion for you.

The texts produced by the toString methods strictly conform to JSON syntax rules. The constructors are more forgiving in the texts they will accept:

  • An extra , (comma) may appear just before the closing bracket.
  • The null value will be inserted when there is ,  (comma) elision.
  • Strings may be quoted with ' (single quote).
  • 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: { } [ ] / \ : , = ; # and if they do not look like numbers and if they are not the reserved words true, false, or null.
  • Values can be separated by ; (semicolon) as well as by , (comma).
See Also:

  • Constructor Details

    • JSONArray

      public JSONArray()
      Construct an empty JSONArray.

    • JSONArray

      public JSONArray(Reader reader)

    • JSONArray

      public JSONArray(IntList list)

    • JSONArray

      public JSONArray(FloatList list)

    • JSONArray

      public JSONArray(StringList list)

  • Method Details

    • parse

      public static JSONArray parse(String source)
      Construct a JSONArray from a source JSON text.
      Parameters:
      source - A string that begins with [ (left bracket) and ends with ] (right bracket).
      Returns:
      null if there is a syntax error.

    • get

      public Object get(int index)
      Get the object value associated with an index.
      Parameters:
      index - must be between 0 and length() - 1
      Returns:
      An object value.
      Throws:
      RuntimeException - If there is no value for the index.

    • getString

      public String getString(int index)
      Gets the String value associated with the specified index.
      Parameters:
      index - must be between 0 and length() - 1
      Returns:
      A string value.
      Throws:
      RuntimeException - If there is no string value for the index.
      See Also:

    • getString

      public String getString(int index, String defaultValue)
      Get the optional string associated with an index. The defaultValue is returned if the key is not found.
      Parameters:
      index - The index must be between 0 and length() - 1.
      defaultValue - The default value.
      Returns:
      A String value.

    • getInt

      public int getInt(int index)
      Gets the int value associated with the specified index.
      Parameters:
      index - must be between 0 and length() - 1
      Returns:
      The value.
      Throws:
      RuntimeException - If the key is not found or if the value is not a number.
      See Also:

    • getInt

      public int getInt(int index, int defaultValue)
      Get the optional int value associated with an index. The defaultValue is returned if there is no value for the index, or if the value is not a number and cannot be converted to a number.
      Parameters:
      index - The index must be between 0 and length() - 1.
      defaultValue - The default value.
      Returns:
      The value.

    • getLong

      public long getLong(int index)
      Get the long value associated with an index.
      Parameters:
      index - The index must be between 0 and length() - 1
      Returns:
      The value.
      Throws:
      RuntimeException - If the key is not found or if the value cannot be converted to a number.

    • getLong

      public long getLong(int index, long defaultValue)
      Get the optional long value associated with an index. The defaultValue is returned if there is no value for the index, or if the value is not a number and cannot be converted to a number.
      Parameters:
      index - The index must be between 0 and length() - 1.
      defaultValue - The default value.
      Returns:
      The value.

    • getFloat

      public float getFloat(int index)
      Gets the float value associated with the specified index.
      Parameters:
      index - must be between 0 and length() - 1
      See Also:

    • getFloat

      public float getFloat(int index, float defaultValue)

    • getDouble

      public double getDouble(int index)
      Get the double value associated with an index.
      Parameters:
      index - must be between 0 and length() - 1
      Returns:
      The value.
      Throws:
      RuntimeException - If the key is not found or if the value cannot be converted to a number.

    • getDouble

      public double getDouble(int index, double defaultValue)
      Get the optional double value associated with an index. The defaultValue is returned if there is no value for the index, or if the value is not a number and cannot be converted to a number.
      Parameters:
      index - subscript
      defaultValue - The default value.
      Returns:
      The value.

    • getBoolean

      public boolean getBoolean(int index)
      Gets the boolean value associated with the specified index.
      Parameters:
      index - must be between 0 and length() - 1
      Returns:
      The truth.
      Throws:
      RuntimeException - If there is no value for the index or if the value is not convertible to boolean.
      See Also:

    • getBoolean

      public boolean getBoolean(int index, boolean defaultValue)
      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).
      Parameters:
      index - The index must be between 0 and length() - 1.
      defaultValue - A boolean default.
      Returns:
      The truth.

    • getJSONArray

      public JSONArray getJSONArray(int index)
      Retrieves the JSONArray with the associated index value.
      Parameters:
      index - must be between 0 and length() - 1
      Returns:
      A JSONArray value.
      Throws:
      RuntimeException - If there is no value for the index. or if the value is not a JSONArray
      See Also:

    • getJSONArray

      public JSONArray getJSONArray(int index, JSONArray defaultValue)

    • getJSONObject

      public JSONObject getJSONObject(int index)
      Retrieves the JSONObject with the associated index value.
      Parameters:
      index - the index value of the object to get
      Returns:
      A JSONObject value.
      Throws:
      RuntimeException - If there is no value for the index or if the value is not a JSONObject
      See Also:

    • getJSONObject

      public JSONObject getJSONObject(int index, JSONObject defaultValue)

    • booleanValues

      public Iterable<Boolean> booleanValues()

    • intValues

      public Iterable<Integer> intValues()

    • longValues

      public Iterable<Long> longValues()

    • floatValues

      public Iterable<Float> floatValues()

    • doubleValues

      public Iterable<Double> doubleValues()

    • arrayValues

      public Iterable<JSONArray> arrayValues()

    • objectValues

      public Iterable<JSONObject> objectValues()

    • getStringArray

      @Deprecated public String[] getStringArray()
      Deprecated.
      Use toStringArray() instead.

    • toStringArray

      public String[] toStringArray()
      Returns the entire JSONArray as an array of Strings. (All values in the array must be of the String type.)
      See Also:

    • toStringList

      public StringList toStringList()

    • getIntArray

      @Deprecated public int[] getIntArray()
      Deprecated.
      Use toIntArray() instead.

    • toIntArray

      public int[] toIntArray()
      Returns the entire JSONArray as an array of ints. (All values in the array must be of the int type.)
      See Also:

    • toIntList

      public IntList toIntList()

    • getLongArray

      @Deprecated public long[] getLongArray()
      Deprecated.
      Use toLongArray() instead.

    • toLongArray

      public long[] toLongArray()
      Get this entire array as a long array. Everything must be an long.

    • toLongList

      public LongList toLongList()

    • getFloatArray

      @Deprecated public float[] getFloatArray()
      Deprecated.
      Use toFloatArray() instead.

    • toFloatArray

      public float[] toFloatArray()
      Get this entire array as a float array. Everything must be an float.

    • toFloatList

      public FloatList toFloatList()

    • getDoubleArray

      @Deprecated public double[] getDoubleArray()
      Deprecated.
      Use toDoubleArray() instead.

    • toDoubleArray

      public double[] toDoubleArray()
      Get this entire array as a double array. Everything must be an double.

    • toDoubleList

      public DoubleList toDoubleList()

    • getBooleanArray

      public boolean[] getBooleanArray()
      Use toBooleanArray() instead.

    • toBooleanArray

      public boolean[] toBooleanArray()
      Get this entire array as a boolean array. Everything must be a boolean.

    • append

      public JSONArray append(String value)
      Appends a new value to the JSONArray, increasing the array's length by one. New values may be of the following types: int, float, String, boolean, JSONObject, or JSONArray.
      Parameters:
      value - a String value
      Returns:
      this.
      See Also:

    • append

      public JSONArray append(int value)
      Append an int value. This increases the array's length by one.
      Parameters:
      value - an int value
      Returns:
      this.

    • append

      public JSONArray append(long value)
      Append an long value. This increases the array's length by one.
      Parameters:
      value - A long value.
      Returns:
      this.

    • append

      public JSONArray append(float value)
      Append a float value. This increases the array's length by one. This will store the value as a double, since there are no floats in JSON.
      Parameters:
      value - a float value
      Returns:
      this.
      Throws:
      RuntimeException - if the value is not finite.

    • append

      public JSONArray append(double value)
      Append a double value. This increases the array's length by one.
      Parameters:
      value - A double value.
      Returns:
      this.
      Throws:
      RuntimeException - if the value is not finite.

    • append

      public JSONArray append(boolean value)
      Append a boolean value. This increases the array's length by one.
      Parameters:
      value - a boolean value
      Returns:
      this.

    • append

      public JSONArray append(JSONArray value)
      Parameters:
      value - a JSONArray value

    • append

      public JSONArray append(JSONObject value)
      Parameters:
      value - a JSONObject value

    • setString

      public JSONArray setString(int index, String value)
      Inserts a new value into the JSONArray at the specified index position. If a value already exists in the specified position, the new value overwrites the old value. If the given index is greater than the length of the JSONArray, then null elements will be added as necessary to pad it out.
      Parameters:
      index - an index value
      value - the value to assign
      Returns:
      this.
      Throws:
      RuntimeException - If the index is negative.
      See Also:

    • setInt

      public JSONArray setInt(int index, int value)
      Inserts a new value into the JSONArray at the specified index position. If a value already exists in the specified position, the new value overwrites the old value. If the given index is greater than the length of the JSONArray, then null elements will be added as necessary to pad it out.
      Parameters:
      index - an index value
      value - the value to assign
      Returns:
      this.
      Throws:
      RuntimeException - If the index is negative.
      See Also:

    • setLong

      public JSONArray setLong(int index, long value)
      Put or replace a long value. If the index is greater than the length of the JSONArray, then null elements will be added as necessary to pad it out.
      Parameters:
      index - The subscript.
      value - A long value.
      Returns:
      this.
      Throws:
      RuntimeException - If the index is negative.

    • setFloat

      public JSONArray setFloat(int index, float value)
      Inserts a new value into the JSONArray at the specified index position. If a value already exists in the specified position, the new value overwrites the old value. If the given index is greater than the length of the JSONArray, then null elements will be added as necessary to pad it out.
      Parameters:
      index - an index value
      value - the value to assign
      Returns:
      this.
      Throws:
      RuntimeException - If the index is negative or if the value is not finite.
      See Also:

    • setDouble

      public JSONArray setDouble(int index, double value)
      Put or replace a double value. If the index is greater than the length of the JSONArray, then null elements will be added as necessary to pad it out.
      Parameters:
      index - The subscript.
      value - A double value.
      Returns:
      this.
      Throws:
      RuntimeException - If the index is negative or if the value is not finite.

    • setBoolean

      public JSONArray setBoolean(int index, boolean value)
      Inserts a new value into the JSONArray at the specified index position. If a value already exists in the specified position, the new value overwrites the old value. If the given index is greater than the length of the JSONArray, then null elements will be added as necessary to pad it out.
      Parameters:
      index - an index value
      value - the value to assign
      Returns:
      this.
      Throws:
      RuntimeException - If the index is negative.
      See Also:

    • setJSONArray

      public JSONArray setJSONArray(int index, JSONArray value)
      Sets the value of the JSONArray with the associated index value.
      Parameters:
      index - the index value to target
      value - the value to assign
      See Also:

    • setJSONObject

      public JSONArray setJSONObject(int index, JSONObject value)
      Sets the value of the JSONObject with the index value.
      Parameters:
      index - the index value to target
      value - the value to assign
      See Also:

    • size

      public int size()
      Gets the total number of elements in a JSONArray (inclusive of null elements).
      Returns:
      The length (or size).
      See Also:

    • isNull

      public boolean isNull(int index)
      Determines if the value associated with the index is null, that is has no defined value (false) or if it has a value (true).
      Parameters:
      index - must be between 0 and length() - 1
      Returns:
      true if the value at the index is null, or if there is no value.

    • remove

      public Object remove(int index)
      Removes the element from a JSONArray in the specified index position. Returns either the value associated with the given index, or null, if there is no value.
      Parameters:
      index - the index value of the element to be removed
      Returns:
      The value that was associated with the index, or null if there was no value.
      See Also:

    • save

      public boolean save(File file, String options)

    • write

      public boolean write(PrintWriter output)

    • write

      public boolean write(PrintWriter output, String options)

    • toString

      public String toString()
      Return the JSON data formatted with two spaces for indents. Chosen to do this since it's the most common case (e.g. with println()). Same as format(2). Use the format() function for more options.
      Overrides:
      toString in class Object

    • format

      public String format(int indentFactor)
      Make a pretty-printed JSON text of this JSONArray. Warning: This method assumes that the data structure is acyclical.
      Parameters:
      indentFactor - The number of spaces to add to each level of indentation. Use -1 to specify no indentation and no newlines.
      Returns:
      a printable, displayable, transmittable representation of the object, beginning with [ (left bracket) and ending with ] (right bracket).

    • join

      public String join(String separator)
      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 acyclic.
      Parameters:
      separator - A string that will be inserted between the elements.
      Returns:
      a string.
      Throws:
      RuntimeException - If the array contains an invalid number.