引用自 JAVA SE API
boolean |
add(E e)
Ensures that this collection contains the specified element (optional operation).
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boolean |
addAll(Collection<? extends E> c)
Adds all of the elements in the specified collection to this collection (optional operation).
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void |
clear()
Removes all of the elements from this collection (optional operation).
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boolean |
contains(Object o)
Returns
true if this collection contains the specified element.
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boolean |
containsAll(Collection<?> c)
Returns
true if this collection contains all of the elements in the specified collection.
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boolean |
isEmpty()
Returns
true if this collection contains no elements.
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abstract Iterator<E> |
iterator()
Returns an iterator over the elements contained in this collection.
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boolean |
remove(Object o)
Removes a single instance of the specified element from this collection, if it is present (optional operation).
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boolean |
removeAll(Collection<?> c)
Removes all of this collection's elements that are also contained in the specified collection (optional operation).
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boolean |
retainAll(Collection<?> c)
Retains only the elements in this collection that are contained in the specified collection (optional operation).
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abstract int |
size()
Returns the number of elements in this collection.
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Object[] |
toArray()
Returns an array containing all of the elements in this collection.
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<T> T[] |
toArray(T[] a)
Returns an array containing all of the elements in this collection; the runtime type of the returned array is that of the specified array.
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String |
toString()
Returns a string representation of this collection.
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