Package org.apache.sis.index.tree
Class PointTree<E>
Object
AbstractCollection<E>
AbstractSet<E>
PointTree<E>
- Type Parameters:
E- the type of elements stored in this tree.
- All Implemented Interfaces:
Serializable,Iterable<E>,Collection<E>,Set<E>,CheckedContainer<E>
A k-dimensional tree index for points.
For k=2, this is a point QuadTree.
For k=3, this is a point Octree.
Higher dimensions are also accepted up to 6 dimensions.
Elements are stored in this
PointTree as arbitrary non-null objects with their coordinates
computed by a user-specified locator function. That function expects an element E
in argument and returns its coordinates as a double[] array.
The coordinates of each elements must be stable, i.e. applying the locator function
twice on the same element must return the same coordinates.
Searches based on element coordinates can be done with the following methods:
The performances of this PointTree depends on two parameters: an estimated bounding box of the points
to be added in this tree and a maximal capacity of leaf nodes (not to be confused with a capacity of the tree).
More details are given in the constructor.
Thread-safety
This class is not thread-safe when the tree content is modified. But if the tree is kept unmodified after construction, then multiple read operations in concurrent threads are safe. Users can synchronize withReadWriteLock (the read lock must be held for complete duration
of iterations or stream consumptions).
Serialization
This tree is serializable if thelocator function and all elements in the tree are also serializable.
However, the serialization details is implementation specific and may change in any future Apache SIS version.
Limitations
Current implementation does not yet support removal of elements.References
Insertion algorithm is based on design of QuadTree index in H. Samet, The Design and Analysis of Spatial Data Structures. Massachusetts: Addison Wesley Publishing Company, 1989.- Since:
- 1.1
- See Also:
Defined in the sis-feature module
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Nested Class Summary
Nested ClassesModifier and TypeClassDescriptionstatic interfaceProvides the coordinates of any element stored inPointTree. -
Field Summary
FieldsModifier and TypeFieldDescriptionstatic final intThe maximum number of dimensions (inclusive) that this class currently supports. -
Constructor Summary
ConstructorsConstructorDescriptionPointTree(Class<E> elementType, Envelope bounds, PointTree.Locator<? super E> locator, int nodeCapacity, boolean parallel) Creates an initially empty k-dimensional tree with the given capacity for each node.PointTree(PointTree<E> other) Creates a new tree initialized to a copy of the given tree. -
Method Summary
Modifier and TypeMethodDescriptionbooleanInserts the specified element into this tree if it is not already present.booleanaddAll(Collection<? extends E> elements) Inserts all elements from the specified collection into this tree if they are not already present.voidclear()Removes all elements from this tree.booleanReturnstrueif this set contains the specified element.Returns the coordinate reference system (CRS) of all points in this tree.final intReturns the number of dimensions of points in this tree.Returns the base type of all elements in this tree.booleanisEmpty()Returns true if this set contains no elements.iterator()Creates an iterator over all elements in this set.Returns a possibly parallel stream with this tree as its source.queryByBoundingBox(Envelope searchRegion) Returns all elements in the given bounding box.intsize()Returns the number of elements in this tree.Creates an iterator over all elements in this set.Methods inherited from class AbstractSet
equals, hashCode, removeAllMethods inherited from class AbstractCollection
containsAll, remove, retainAll, toArray, toArray, toStringMethods inherited from class Object
clone, finalize, getClass, notify, notifyAll, wait, wait, waitMethods inherited from interface Collection
removeIf, stream, toArrayMethods inherited from interface Set
containsAll, remove, retainAll, toArray, toArray
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Field Details
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MAXIMUM_DIMENSIONS
public static final int MAXIMUM_DIMENSIONSThe maximum number of dimensions (inclusive) that this class currently supports. Current maximum is 6. This restriction come from 2⁶ = 64.- See Also:
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Constructor Details
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PointTree
Creates a new tree initialized to a copy of the given tree. This copy constructor shares some data structure from theothertree for reducing memory usage, but the two trees are nevertheless independent (changes in a tree does not affect the other tree).- Parameters:
other- the other tree to copy.
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PointTree
public PointTree(Class<E> elementType, Envelope bounds, PointTree.Locator<? super E> locator, int nodeCapacity, boolean parallel) Creates an initially empty k-dimensional tree with the given capacity for each node. The number of dimensions of the given envelope determines the number of dimensions of points in this tree. The positions computed bylocatormust have the same number of dimensions than the given envelope.The
boundsargument specifies the expected region of points to be added in thisPointTree. Those bounds do not need to be exact;PointTreewill work even if some points are located outside those bounds. However, performances will be better if the envelope center is close to the median of the points to be inserted in thePointTree, and if the majority of points are inside those bounds.The given
nodeCapacityis a threshold value controlling when the content of a node should be splited into smaller children nodes. That capacity should be a relatively small number, for example 10. Determining the most efficient value may require benchmarking.- Parameters:
elementType- the base type of all elements in this tree.bounds- bounds of the region of data to be inserted in the k-dimensional tree.locator- function computing the position of any element in this tree.nodeCapacity- the capacity of each node (not to be confused with a capacity of the tree).parallel- whether the stream can be parallel by default. Should befalseif the givenlocatoris not thread-safe.
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Method Details
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getCoordinateReferenceSystem
Returns the coordinate reference system (CRS) of all points in this tree. The CRS is taken from the envelope given in argument to the constructor.- Returns:
- the CRS of all points in this tree, if presents.
- See Also:
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getDimension
public final int getDimension()Returns the number of dimensions of points in this tree.- Returns:
- the number of dimensions of points in this tree.
- See Also:
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getElementType
Returns the base type of all elements in this tree.- Specified by:
getElementTypein interfaceCheckedContainer<E>- Returns:
- the element type.
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clear
public void clear()Removes all elements from this tree.- Specified by:
clearin interfaceCollection<E>- Specified by:
clearin interfaceSet<E>- Overrides:
clearin classAbstractCollection<E>
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isEmpty
public boolean isEmpty()Returns true if this set contains no elements.- Specified by:
isEmptyin interfaceCollection<E>- Specified by:
isEmptyin interfaceSet<E>- Overrides:
isEmptyin classAbstractCollection<E>- Returns:
- whether this set is empty.
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size
public int size()Returns the number of elements in this tree.- Specified by:
sizein interfaceCollection<E>- Specified by:
sizein interfaceSet<E>- Specified by:
sizein classAbstractCollection<E>- Returns:
- the number of elements in this tree, or
Integer.MAX_VALUEif there is more elements than what anintcan represent.
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add
Inserts the specified element into this tree if it is not already present.- Specified by:
addin interfaceCollection<E>- Specified by:
addin interfaceSet<E>- Overrides:
addin classAbstractCollection<E>- Parameters:
element- the element to insert.- Returns:
trueif the element has been added, orfalseif it was already present.- Throws:
NullPointerException- if the given element is null.
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addAll
Inserts all elements from the specified collection into this tree if they are not already present.- Specified by:
addAllin interfaceCollection<E>- Specified by:
addAllin interfaceSet<E>- Overrides:
addAllin classAbstractCollection<E>- Parameters:
elements- the elements to insert.- Returns:
trueif at least one element has been added.- Throws:
NullPointerException- if an element is null.
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contains
Returnstrueif this set contains the specified element.- Specified by:
containsin interfaceCollection<E>- Specified by:
containsin interfaceSet<E>- Overrides:
containsin classAbstractCollection<E>- Parameters:
element- the object to search.- Returns:
- whether this set contains the specified element.
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iterator
Creates an iterator over all elements in this set. In current implementation, the iterator does not support element removal. -
spliterator
Creates an iterator over all elements in this set. The iterator characteristics are sized, distinct andnon-null.- Specified by:
spliteratorin interfaceCollection<E>- Specified by:
spliteratorin interfaceIterable<E>- Specified by:
spliteratorin interfaceSet<E>
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parallelStream
Returns a possibly parallel stream with this tree as its source. It is allowable for this method to return a sequential stream.- Specified by:
parallelStreamin interfaceCollection<E>- Returns:
- a possibly parallel stream over the elements in this tree.
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queryByBoundingBox
Returns all elements in the given bounding box. The given envelope shall be in the same CRS than the points in this tree (this is currently not verified). The returned stream may be parallel by default, depending on the argument given to the constructor. If the action to be applied on the stream cannot be parallel, then user should invokeBaseStream.sequential()explicitly.- Parameters:
searchRegion- envelope representing the rectangular search region.- Returns:
- elements that are in the given search region (bounds inclusive).
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