Documentation of 'processing.data.JSONArray' Java class
JSONArray
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processing.data

Class JSONArray


  • public class JSONArray
extends java.lang.Object
    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:
    JSONObject, PApplet.loadJSONObject(String), PApplet.loadJSONArray(String), PApplet.saveJSONObject(JSONObject, String), PApplet.saveJSONArray(JSONArray, String)

    • Method Summary

      All Methods Static Methods Instance Methods Concrete Methods 
      Modifier and Type Method and Description
      JSONArray append(boolean value)
      Append a boolean value.
      JSONArray append(double value)
      Append a double value.
      JSONArray append(float value)
      Append a float value.
      JSONArray append(int value)
      Append an int value.
      JSONArray append(JSONArray value) 
      JSONArray append(JSONObject value) 
      JSONArray append(long value)
      Append an long value.
      JSONArray append(java.lang.String value)
      Append an String value.
      java.lang.String format(int indentFactor)
      Make a pretty-printed JSON text of this JSONArray.
      boolean getBoolean(int index)
      Get the boolean value associated with an index.
      boolean getBoolean(int index, boolean defaultValue)
      Get the optional boolean value associated with an index.
      boolean[] getBooleanArray()
      Get this entire array as a boolean array.
      double getDouble(int index)
      Get the double value associated with an index.
      double getDouble(int index, double defaultValue)
      Get the optional double value associated with an index.
      double[] getDoubleArray()
      Get this entire array as a double array.
      float getFloat(int index)
      Get a value from an index as a float.
      float getFloat(int index, float defaultValue) 
      float[] getFloatArray()
      Get this entire array as a float array.
      int getInt(int index)
      Get the int value associated with an index.
      int getInt(int index, int defaultValue)
      Get the optional int value associated with an index.
      int[] getIntArray()
      Get this entire array as an int array.
      JSONArray getJSONArray(int index)
      Get the JSONArray associated with an index.
      JSONArray getJSONArray(int index, JSONArray defaultValue) 
      JSONObject getJSONObject(int index)
      Get the JSONObject associated with an index.
      JSONObject getJSONObject(int index, JSONObject defaultValue) 
      long getLong(int index)
      Get the long value associated with an index.
      long getLong(int index, long defaultValue)
      Get the optional long value associated with an index.
      long[] getLongArray()
      Get this entire array as a long array.
      java.lang.String getString(int index)
      Get the string associated with an index.
      java.lang.String getString(int index, java.lang.String defaultValue)
      Get the optional string associated with an index.
      java.lang.String[] getStringArray()
      Get this entire array as a String array.
      boolean isNull(int index)
      Determine if the value is null.
      java.lang.String join(java.lang.String separator)
      Make a string from the contents of this JSONArray.
      static JSONArray parse(java.lang.String source)
      Construct a JSONArray from a source JSON text.
      java.lang.Object remove(int index)
      Remove an index and close the hole.
      boolean save(java.io.File file, java.lang.String options) 
      JSONArray setBoolean(int index, boolean value)
      Put or replace a boolean value in the JSONArray.
      JSONArray setDouble(int index, double value)
      Put or replace a double value.
      JSONArray setFloat(int index, float value)
      Put or replace a float value.
      JSONArray setInt(int index, int value)
      Put or replace an int value.
      JSONArray setJSONArray(int index, JSONArray value) 
      JSONArray setJSONObject(int index, JSONObject value) 
      JSONArray setLong(int index, long value)
      Put or replace a long value.
      JSONArray setString(int index, java.lang.String value)
      Put or replace a String value.
      int size()
      Get the number of elements in the JSONArray, included nulls.
      java.lang.String toString()
      Return the JSON data formatted with two spaces for indents.
      boolean write(java.io.PrintWriter output) 
      boolean write(java.io.PrintWriter output, java.lang.String options) 

      • Methods inherited from class java.lang.Object

        equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

    • Constructor Detail

      • JSONArray

        public JSONArray()
        Construct an empty JSONArray.

      • JSONArray

        public JSONArray(java.io.Reader reader)

      • JSONArray

        public JSONArray(IntList list)

      • JSONArray

        public JSONArray(FloatList list)

    • Method Detail

      • parse

        public static JSONArray parse(java.lang.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.

      • getString

        public java.lang.String getString(int index)
        Get the string associated with an index.
        Parameters:
        index - must be between 0 and length() - 1
        Returns:
        A string value.
        Throws:
        java.lang.RuntimeException - If there is no string value for the index.
        See Also:
        getInt(int), getFloat(int), getBoolean(int)

      • getString

        public java.lang.String getString(int index,
                                  java.lang.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)
        Get the int value associated with an index.
        Parameters:
        index - must be between 0 and length() - 1
        Returns:
        The value.
        Throws:
        java.lang.RuntimeException - If the key is not found or if the value is not a number.
        See Also:
        getFloat(int), getString(int), getBoolean(int)

      • 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:
        java.lang.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)
        Get a value from an index as a float. JSON uses 'double' values internally, so this is simply getDouble() cast to a float.
        Parameters:
        index - must be between 0 and length() - 1
        See Also:
        getInt(int), getString(int), getBoolean(int)

      • 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:
        java.lang.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)
        Get the boolean value associated with an index. The string values "true" and "false" are converted to boolean.
        Parameters:
        index - must be between 0 and length() - 1
        Returns:
        The truth.
        Throws:
        java.lang.RuntimeException - If there is no value for the index or if the value is not convertible to boolean.
        See Also:
        getInt(int), getFloat(int), getString(int)

      • 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.

      • getStringArray

        public java.lang.String[] getStringArray()
        Get this entire array as a String array.
        See Also:
        getIntArray()

      • getIntArray

        public int[] getIntArray()
        Get this entire array as an int array. Everything must be an int.
        See Also:
        getStringArray()

      • getLongArray

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

      • getFloatArray

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

      • getDoubleArray

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

      • getBooleanArray

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

      • append

        public JSONArray append(java.lang.String value)
        Append an String value. This increases the array's length by one.
        Parameters:
        value - a String value
        Returns:
        this.
        See Also:
        size(), remove(int)

      • 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:
        java.lang.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:
        java.lang.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

      • setString

        public JSONArray setString(int index,
                           java.lang.String value)
        Put or replace a String 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 - an index value
        value - the value to assign
        Returns:
        this.
        Throws:
        java.lang.RuntimeException - If the index is negative.
        See Also:
        setInt(int, int), setFloat(int, float), setBoolean(int, boolean)

      • setInt

        public JSONArray setInt(int index,
                        int value)
        Put or replace an int 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 - an index value
        value - the value to assign
        Returns:
        this.
        Throws:
        java.lang.RuntimeException - If the index is negative.
        See Also:
        setFloat(int, float), setString(int, String), setBoolean(int, boolean)

      • 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:
        java.lang.RuntimeException - If the index is negative.

      • setFloat

        public JSONArray setFloat(int index,
                          float value)
        Put or replace a float value. If the index is greater than the length of the JSONArray, then null elements will be added as necessary to pad it out. There are no 'double' values in JSON, so this is passed to setDouble(value).
        Parameters:
        index - an index value
        value - the value to assign
        Returns:
        this.
        Throws:
        java.lang.RuntimeException - If the index is negative or if the value is not finite.
        See Also:
        setInt(int, int), setString(int, String), setBoolean(int, boolean)

      • 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:
        java.lang.RuntimeException - If the index is negative or if the value is not finite.

      • setBoolean

        public JSONArray setBoolean(int index,
                            boolean value)
        Put or replace a boolean value in the JSONArray. 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 - an index value
        value - the value to assign
        Returns:
        this.
        Throws:
        java.lang.RuntimeException - If the index is negative.
        See Also:
        setInt(int, int), setFloat(int, float), setString(int, String)

      • size

        public int size()
        Get the number of elements in the JSONArray, included nulls.
        Returns:
        The length (or size).
        See Also:
        append(String), remove(int)

      • isNull

        public boolean isNull(int index)
        Determine if the value is null.
        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 java.lang.Object remove(int index)
        Remove an index and close the hole.
        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:
        size(), append(String)

      • save

        public boolean save(java.io.File file,
                    java.lang.String options)

      • write

        public boolean write(java.io.PrintWriter output)

      • write

        public boolean write(java.io.PrintWriter output,
                     java.lang.String options)

      • toString

        public java.lang.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 java.lang.Object

      • format

        public java.lang.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 java.lang.String join(java.lang.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:
        java.lang.RuntimeException - If the array contains an invalid number.
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