# Basic Java collections
#
# ~~~
# var coll = new JavaArray(2)
#
# assert coll[0].is_java_null
# coll[0] = "zero".to_java_string
# coll[1] = "one".to_java_string
#
# assert coll.length == 2
# assert coll.first.to_s == "zero"
# assert coll[1].to_s == "one"
# assert [for e in coll do e.to_s] == ["zero", "one"]
# ~~~
module collections

import ffi_support

# Java primitive array
#
# These have fixed size so they offer the same services as `SequenceRead` and
# `[]=`, but would not support `Sequence::add`.
extern class AbstractJavaArray[E: Object]
	super SequenceRead[E]
	super JavaObject

	# Set the `value` at `key`
	fun []=(key: Int, value: E) is abstract

	redef fun iterator do return new JavaArrayIterator[E](self)

	redef fun reverse_iterator do return new JavaArrayReverseIterator[E](self)
end

# Java primitive array `int[]`
extern class JavaIntArray in "Java" `{ int[] `}
	super AbstractJavaArray[Int]

	# Get a new array of the given `size`
	new (size: Int) in "Java" `{ return new int[(int)size]; `}

	redef fun [](i) in "Java" `{ return self[(int)i]; `}

	redef fun []=(i, e) in "Java" `{ self[(int)i] = (int)e; `}

	redef fun length in "Java" `{ return self.length; `}
end

# Java primitive array `short[]`
extern class JavaShortArray in "Java" `{ short[] `}
	super AbstractJavaArray[Int]

	# Get a new array of the given `size`
	new (size: Int) in "Java" `{ return new short[(int)size]; `}

	redef fun [](i) in "Java" `{ return (short)self[(int)i]; `}

	redef fun []=(i, e) in "Java" `{ self[(int)i] = (short)e; `}

	redef fun length in "Java" `{ return self.length; `}
end

# Java primitive array `long[]`
extern class JavaLongArray in "Java" `{ long[] `}
	super AbstractJavaArray[Int]

	# Get a new array of the given `size`
	new (size: Int) in "Java" `{ return new long[(int)size]; `}

	redef fun [](i) in "Java" `{ return self[(int)i]; `}

	redef fun []=(i, e) in "Java" `{ self[(int)i] = (long)e; `}

	redef fun length in "Java" `{ return self.length; `}
end

# Java primitive array `float[]`
#
# Note that Nit `Float` is the size of a double, so storing them in a
# `JavaFloatArray` may lead to a loss of precision.
extern class JavaFloatArray in "Java" `{ float[] `}
	super AbstractJavaArray[Float]

	# Get a new array of the given `size`
	new(size: Int) in "Java" `{ return new float[(int)size]; `}

	redef fun [](i) in "Java" `{ return (double)self[(int)i]; `}

	redef fun []=(i, e) in "Java" `{ self[(int)i] = (float)e; `}

	redef fun length in "Java" `{ return self.length; `}
end

# Java primitive array `double[]`
extern class JavaDoubleArray in "Java" `{ double[] `}
	super AbstractJavaArray[Float]

	# Get a new array of the given `size`
	new(size: Int) in "Java" `{ return new double[(int)size]; `}

	redef fun [](i) in "Java" `{ return self[(int)i]; `}

	redef fun []=(i, e) in "Java" `{ self[(int)i] = (float)e; `}

	redef fun length in "Java" `{ return self.length; `}
end

# Java primitive array `Object[]`
extern class JavaArray in "Java" `{ java.lang.Object[] `}
	super AbstractJavaArray[JavaObject]

	# Get a new array of the given `size`
	new(size: Int) in "Java" `{ return new Object[(int)size]; `}

	redef fun [](i) in "Java" `{ return self[(int)i]; `}

	redef fun []=(i, e) in "Java" `{ self[(int)i] = e; `}

	redef fun length in "Java" `{ return self.length; `}
end

# Java primitive array `boolean[]`
extern class JavaBoolArray in "Java" `{ boolean[] `}
	super AbstractJavaArray[Bool]

	# Get a new array of the given `size`
	new (size: Int) in "Java" `{ return new boolean[(int)size]; `}

	redef fun [](i) in "Java" `{ return self[(int)i]; `}

	redef fun []=(i, e) in "Java" `{self[(int)i] = (boolean)e; `}

	redef fun length in "Java" `{ return self.length; `}
end

# Java primitive array `byte[]`
extern class JavaByteArray in "Java" `{ byte[] `}
	super AbstractJavaArray[Int]

	# Get a new array of the given `size`
	new (size: Int) in "Java" `{ return new byte[(int)size]; `}

	redef fun [](i) in "Java" `{ return (byte)self[(int)i]; `}

	redef fun []=(i, e) in "Java" `{ self[(int)i] = (byte)e; `}

	redef fun length in "Java" `{ return self.length; `}
end

# Java primitive array `char[]`
extern class JavaCharArray in "Java" `{ char[] `}
	super AbstractJavaArray[Char]

	# Get a new array of the given `size`
	new (size: Int) in "Java" `{ return new char[(int)size]; `}

	redef fun [](i) in "Java" `{ return (char)self[(int)i]; `}

	redef fun []=(i, e) in "Java" `{ self[(int)i] = (char)e; `}

	redef fun length in "Java" `{ return self.length; `}
end

# An `Iterator` on Java primitive arrays
private class JavaArrayIterator[E: Object]
	super IndexedIterator[E]

	var array: AbstractJavaArray[E]

	redef fun item do return array[index]

	redef fun is_ok do return index < array.length

	redef fun next do index += 1

	redef var index = 0
end

# A reverse `Iterator` on Java primitive arrays
private class JavaArrayReverseIterator[E: Object]
	super IndexedIterator[E]

	var array: AbstractJavaArray[E]

	redef fun item do return array[index]

	redef fun is_ok do return index >= 0

	redef fun next do index -= 1

	redef var index = array.length - 1
end