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| 1 | +package org.python.modules.itertools; |
| 2 | + |
| 3 | +import org.python.core.ArgParser; |
| 4 | +import org.python.core.PyIterator; |
| 5 | +import org.python.core.PyObject; |
| 6 | +import org.python.core.PyString; |
| 7 | +import org.python.core.PyType; |
| 8 | +import org.python.expose.ExposedGet; |
| 9 | +import org.python.expose.ExposedMethod; |
| 10 | +import org.python.expose.ExposedNew; |
| 11 | +import org.python.expose.ExposedType; |
| 12 | + |
| 13 | +import java.util.ArrayList; |
| 14 | +import java.util.List; |
| 15 | + |
| 16 | +@ExposedType(name = "itertools.count", base = PyObject.class) |
| 17 | +public class cycle extends PyObject { |
| 18 | + |
| 19 | + public static final PyType TYPE = PyType.fromClass(cycle.class); |
| 20 | + private PyIterator iter; |
| 21 | + |
| 22 | + @ExposedGet |
| 23 | + public static PyString __doc__ = new PyString( |
| 24 | + "cycle(iterable) --> cycle object\n\n" + |
| 25 | + "Return elements from the iterable until it is exhausted.\n" + |
| 26 | + "Then repeat the sequence indefinitely."); |
| 27 | + |
| 28 | + public cycle() { |
| 29 | + super(); |
| 30 | + } |
| 31 | + |
| 32 | + public cycle(PyType subType) { |
| 33 | + super(subType); |
| 34 | + } |
| 35 | + |
| 36 | + /** |
| 37 | + * Creates an iterator that iterates over an iterable, saving the values for each iteration. |
| 38 | + * When the iterable is exhausted continues to iterate over the saved values indefinitely. |
| 39 | + */ |
| 40 | + public cycle(PyObject sequence) { |
| 41 | + super(); |
| 42 | + cycle___init__(sequence); |
| 43 | + } |
| 44 | + |
| 45 | + @ExposedNew |
| 46 | + @ExposedMethod |
| 47 | + final void cycle___init__(final PyObject[] args, String[] kwds) { |
| 48 | + ArgParser ap = new ArgParser("cycle", args, kwds, new String[] {"iterable"}, 1); |
| 49 | + ap.noKeywords(); |
| 50 | + cycle___init__(ap.getPyObject(0)); |
| 51 | + } |
| 52 | + |
| 53 | + private void cycle___init__(final PyObject sequence) { |
| 54 | + iter = new itertools.ItertoolsIterator() { |
| 55 | + List<PyObject> saved = new ArrayList<PyObject>(); |
| 56 | + int counter = 0; |
| 57 | + PyObject iterator = sequence.__iter__(); |
| 58 | + |
| 59 | + boolean save = true; |
| 60 | + |
| 61 | + public PyObject __iternext__() { |
| 62 | + if (save) { |
| 63 | + PyObject obj = nextElement(iterator); |
| 64 | + if (obj != null) { |
| 65 | + saved.add(obj); |
| 66 | + return obj; |
| 67 | + } else { |
| 68 | + save = false; |
| 69 | + } |
| 70 | + } |
| 71 | + if (saved.size() == 0) { |
| 72 | + return null; |
| 73 | + } |
| 74 | + |
| 75 | + // pick element from saved List |
| 76 | + if (counter >= saved.size()) { |
| 77 | + // start over again |
| 78 | + counter = 0; |
| 79 | + } |
| 80 | + return saved.get(counter++); |
| 81 | + } |
| 82 | + |
| 83 | + }; |
| 84 | + } |
| 85 | + |
| 86 | + @ExposedMethod |
| 87 | + public PyObject __iter__() { |
| 88 | + return iter; |
| 89 | + } |
| 90 | + |
| 91 | + @ExposedMethod |
| 92 | + public PyObject next() { |
| 93 | + return iter.next(); |
| 94 | + } |
| 95 | + |
| 96 | +} |
| 97 | + |
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