36 lines
1.3 KiB
Go
36 lines
1.3 KiB
Go
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package iterator
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// Factory is the interface that wraps the NewIterator method. The
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// NewIterator() creates either UID or thread iterators and ensures that both
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// types of iterators implement the same iteration direction.
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type Factory interface {
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NewIterator(a interface{}) Iterator
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}
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// Iterator implements an interface for iterating over UID or thread data. If
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// Next() returns true, the current value of the iterator can be read with
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// Value(). The return value of Value() is an interface{} type which needs to
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// be cast to the correct type.
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//
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// The iterators are implemented such that the first returned value always
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// represents the top message in the message list. Hence, StartIndex() would
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// return the index of the top message whereas EndIndex() returns the index of
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// message at the bottom of the list.
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type Iterator interface {
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Next() bool
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Value() interface{}
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StartIndex() int
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EndIndex() int
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}
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// NewFactory creates an iterator factory. When reverse is true, the iterators
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// are reversed in the sense that the lowest UID messages are displayed at the
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// top of the message list. Otherwise, the default order is with the highest
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// UID message on top.
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func NewFactory(reverse bool) Factory {
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if reverse {
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return &reverseFactory{}
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}
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return &defaultFactory{}
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}
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