Class Value

    • Method Detail

      • isDefined

        public boolean isDefined()
        Returns true if this Value is not Absent.
        Specified by:
        isDefined in class Item
      • isDistinct

        public boolean isDistinct()
        Returns true if this Value is neither Extant nor Absent.
        Specified by:
        isDistinct in class Item
      • key

        public final Value key()
        Always returns Absent because a Value can't be a Field, so it can't have a key component.
        Specified by:
        key in class Item
      • toValue

        public final Value toValue()
        Always returns this because every Value is its own value component.
        Specified by:
        toValue in class Item
      • tag

        public String tag()
        Returns the key string of the first member of this Value, if this Value is a Record, and its first member is an Attr; otherwise returns null if this Value is not a Record, or if this Value is a Record whose first member is not an Attr.

        Used to concisely get the name of the discriminating attribute of a structure. The tag can be used to discern the nominal type of a polymorphic structure, similar to an XML element tag.

        Specified by:
        tag in class Item
      • target

        public Value target()
        Returns the flattened members of this Value after all attributes have been removed, if this Value is a Record; otherwise returns this if this Value is not a Record.

        Used to concisely get the scalar value of an attributed structure. An attributed structure is a Record with one or more attributes that modify one or more other members.

        Specified by:
        target in class Item
      • flattened

        public Value flattened()
        Returns the sole member of this Value, if this Value is a Record with exactly one member, and its member is a Value; returns Extant if this Value is an empty Record; otherwise returns this if this Value is a Record with more than one member, or if this Value is not a Record.

        Used to convert a unary Record into its member Value. Facilitates writing code that treats a unary Record equivalently to a bare Value.

        Specified by:
        flattened in class Item
      • unflattened

        public Record unflattened()
        Returns this if this Value is a Record; returns a Record containing just this Value, if this Value is distinct; otherwise returns an empty Record if this Value is Extant or Absent. Facilitates writing code that treats a bare Value equivalently to a unary Record.
        Specified by:
        unflattened in class Item
      • header

        public Value header​(String tag)
        Returns the value of the first member of this Value, if this Value is a Record, and its first member is an Attr whose key string is equal to tag; otherwise returns Absent if this Value is not a Record, or if this Value is a Record whose first member is not an Attr, or if this Value is a Record whose first member is an Attr whose key does not equal the tag.

        Used to conditionally get the value of the head Attr of a structure, if and only if the key string of the head Attr is equal to the tag. Can be used to check if a structure might conform to a nominal type named tag, while simultaneously getting the value of the tag attribute.

        Specified by:
        header in class Item
      • headers

        public Record headers​(String tag)
        Returns the unflattened header of this Value, if this Value is a Record, and its first member is an Attr whose key string is equal to tag; otherwise returns null.

        The headers of the tag attribute of a structure are like the attributes of an XML element tag; through unlike an XML element, tag attribute headers are not limited to string keys and values.

        Specified by:
        headers in class Item
      • head

        public Item head()
        Returns the first member of this Value, if this Value is a non-empty Record; otherwise returns Absent.
        Specified by:
        head in class Item
      • tail

        public Record tail()
        Returns a view of all but the first member of this Value, if this Value is a non-empty Record; otherwise returns an empty Record if this Value is not a Record, of if this Value is itself an empty Record.
        Specified by:
        tail in class Item
      • body

        public Value body()
        Returns the flattened tail of this Value. Used to recursively deconstruct a structure, terminating with its last Value, rather than a unary Record containing its last value, if the structure ends with a Value member.
        Specified by:
        body in class Item
      • length

        public int length()
        Returns the number of members contained in this Value, if this Value is a Record; otherwise returns 0 if this Value is not a Record.
        Specified by:
        length in class Item
      • contains

        public boolean contains​(Item item)
        Returns true if this Value is a Record that has a member equal to item; otherwise returns false if this Value is not a Record, or if this Value is a Record, but has no member equal to item.
        Specified by:
        contains in class Item
      • containsKey

        public boolean containsKey​(Value key)
        Returns true if this Value is a Record that has a Field member with a key that is equal to the given key; otherwise returns false if this Value is not a Record, or if this Value is a Record, but has no Field member with a key equal to the given key.
        Specified by:
        containsKey in class Item
      • containsKey

        public boolean containsKey​(String key)
        Returns true if this Value is a Record that has a Field with a Text key whose string value is equal to the given key; otherwise returns false if this Value is not a Record, or if this Value is a Record, but has no Field member with a Text key whose string value equals the given key. Equivalent to containsKey(Value), but avoids boxing the key string into a Text value.
        Specified by:
        containsKey in class Item
      • containsValue

        public boolean containsValue​(Value value)
        Returns true if this Value is a Record that has a Field member with a value that is equal to the given value; otherwise returns false if this Value is not a Record, or if this Value is a Record, but has no Field member with a value equal to the given value.
        Specified by:
        containsValue in class Item
      • get

        public Value get​(Value key)
        Returns the value of the last Field member of this Value whose key is equal to the given key; returns Absent if this Value is not a Record, or if this Value is a Record, but has no Field member with a key equal to the given key.
        Specified by:
        get in class Item
      • get

        public Value get​(String key)
        Returns the value of the last Field member of this Value with a Text key whose string value is equal to the given key; returns Absent if this Value is not a Record, or if this Value is a Record, but has no Field member with a Text key whose string value equals the given key. Equivalent to get(Value), but avoids boxing the key string into a Text value.
        Specified by:
        get in class Item
      • getAttr

        public Value getAttr​(Text key)
        Returns the value of the last Attr member of this Value whose key is equal to the given key; returns Absent if this Value is not a Record, or if this Value is a Record, but has no Attr member with a key equal to the given key.
        Specified by:
        getAttr in class Item
      • getAttr

        public Value getAttr​(String key)
        Returns the value of the last Attr member of this Value with a Text key whose string value is equal to the given key; returns Absent if this Value is not a Record, or if this Value is a Record, but has no Attr member with a Text key whose string value equals the given key. Equivalent to getAttr(Text), but avoids boxing the key string into a Text value.
        Specified by:
        getAttr in class Item
      • getSlot

        public Value getSlot​(Value key)
        Returns the value of the last Slot member of this Value whose key is equal to the given key; returns Absent if this Value is not a Record, or if this Value is a Record, but has no Slot member with a key equal to the given key.
        Specified by:
        getSlot in class Item
      • getSlot

        public Value getSlot​(String key)
        Returns the value of the last Slot member of this Value with a Text key whose string value is equal to the given key; returns Absent if this Value is not a Record, or if this Value is a Record, but has no Slot member with a Text key whose string value equals the given key. Equivalent to getSlot(Value), but avoids boxing the key string into a Text value.
        Specified by:
        getSlot in class Item
      • getField

        public Field getField​(Value key)
        Returns the last Field member of this Value whose key is equal to the given key; returns null if this Value is not a Record, or if this Value is a Record, but has no Field member with a key equal to the given key.
        Specified by:
        getField in class Item
      • getField

        public Field getField​(String key)
        Returns the last Field member of this Value with a Text key whose string value is equal to the given key; returns null if this Value is not a Record, or if this Value is a Record, but has no Field member with a Text key whose string value equals the given key. Equivalent to getField(Value), but avoids boxing the key string into a Text value.
        Specified by:
        getField in class Item
      • getItem

        public Item getItem​(int index)
        Returns the member of this Value at the given index, if this Value is a Record, and the index is greater than or equal to zero, and less than the length of the Record; otherwise returns Absent if this Value is not a Record, or if this Value is a Record, but the index is out of bounds.
        Specified by:
        getItem in class Item
      • conditional

        public Value conditional​(Value thenTerm,
                                 Value elseTerm)
      • bitwiseOr

        public Value bitwiseOr​(Value that)
      • bitwiseXor

        public Value bitwiseXor​(Value that)
      • bitwiseAnd

        public Value bitwiseAnd​(Value that)
      • not

        public Value not()
        Specified by:
        not in class Item
      • stringValue

        public String stringValue​(String orElse)
        Converts this Value into a String value, if possible; otherwise returns orElse if this Value can't be converted into a string value.
        Specified by:
        stringValue in class Item
      • byteValue

        public byte byteValue()
        Converts this Value into a primitive byte value, if possible.
        Specified by:
        byteValue in class Item
        Throws:
        UnsupportedOperationException - if this Value can't be converted into a primitive byte value.
      • byteValue

        public byte byteValue​(byte orElse)
        Converts this Value into a primitive byte value, if possible; otherwise returns orElse if this Value can't be converted into a primitive byte value.
        Specified by:
        byteValue in class Item
      • shortValue

        public short shortValue()
        Converts this Value into a primitive short value, if possible.
        Specified by:
        shortValue in class Item
        Throws:
        UnsupportedOperationException - if this Value can't be converted into a primitive short value.
      • shortValue

        public short shortValue​(short orElse)
        Converts this Value into a primitive short value, if possible; otherwise returns orElse if this Value can't be converted into a primitive short value.
        Specified by:
        shortValue in class Item
      • intValue

        public int intValue()
        Converts this Value into a primitive int value, if possible.
        Specified by:
        intValue in class Item
        Throws:
        UnsupportedOperationException - if this Value can't be converted into a primitive int value.
      • intValue

        public int intValue​(int orElse)
        Converts this Value into a primitive int value, if possible; otherwise returns orElse if this Value can't be converted into a primitive int value.
        Specified by:
        intValue in class Item
      • longValue

        public long longValue()
        Converts this Value into a primitive long value, if possible.
        Specified by:
        longValue in class Item
        Throws:
        UnsupportedOperationException - if this Value can't be converted into a primitive long value.
      • longValue

        public long longValue​(long orElse)
        Converts this Value into a primitive long value, if possible; otherwise returns orElse if this Value can't be converted into a primitive long value.
        Specified by:
        longValue in class Item
      • floatValue

        public float floatValue()
        Converts this Value into a primitive float value, if possible.
        Specified by:
        floatValue in class Item
        Throws:
        UnsupportedOperationException - if this Value can't be converted into a primitive float value.
      • floatValue

        public float floatValue​(float orElse)
        Converts this Value into a primitive float value, if possible; otherwise returns orElse if this Value can't be converted into a primitive float value.
        Specified by:
        floatValue in class Item
      • doubleValue

        public double doubleValue()
        Converts this Value into a primitive double value, if possible.
        Specified by:
        doubleValue in class Item
        Throws:
        UnsupportedOperationException - if this Value can't be converted into a primitive double value.
      • doubleValue

        public double doubleValue​(double orElse)
        Converts this Value into a primitive double value, if possible; otherwise returns orElse if this Value can't be converted into a primitive double value.
        Specified by:
        doubleValue in class Item
      • integerValue

        public BigInteger integerValue​(BigInteger orElse)
        Converts this Value into a BigInteger value, if possible; otherwise returns orElse if this Value can't be converted into a BigInteger value.
        Specified by:
        integerValue in class Item
      • numberValue

        public Number numberValue​(Number orElse)
        Converts this Value into a Number object, if possible; otherwise returns orElse if this Value can't be converted into a Number object.
        Specified by:
        numberValue in class Item
      • charValue

        public char charValue()
        Converts this Value into a primitive char value, if possible.
        Specified by:
        charValue in class Item
        Throws:
        UnsupportedOperationException - if this Value can't be converted into a primitive char value.
      • charValue

        public char charValue​(char orElse)
        Converts this Value into a primitive char value, if possible; otherwise returns orElse if this Value can't be converted into a primitive char value.
        Specified by:
        charValue in class Item
      • booleanValue

        public boolean booleanValue()
        Converts this Value into a primitive boolean value, if possible.
        Specified by:
        booleanValue in class Item
        Throws:
        UnsupportedOperationException - if this Value can't be converted into a primitive boolean value.
      • booleanValue

        public boolean booleanValue​(boolean orElse)
        Converts this Value into a primitive boolean value, if possible; otherwise returns orElse if this Value can't be converted into a primitive boolean value.
        Specified by:
        booleanValue in class Item
      • isAliased

        public boolean isAliased()
        Specified by:
        isAliased in class Item
      • isMutable

        public boolean isMutable()
        Specified by:
        isMutable in class Item
      • alias

        public void alias()
        Specified by:
        alias in class Item
      • commit

        public Value commit()
        Description copied from class: Item
        Flags this Item as immutable, recursively if it is a Record, then returns this Item.
        Specified by:
        commit in class Item
      • empty

        public static Value empty()
      • extant

        public static Value extant()
      • absent

        public static Value absent()
      • fromObject

        public static Value fromObject​(Object object)