com.bbn.openmap.geo
Class ExtentIndex.AbstractExtentIndex

java.lang.Object
  java.util.AbstractCollection
      com.bbn.openmap.geo.ExtentIndex.AbstractExtentIndex

All Implemented Interfaces:

ExtentIndex, java.lang.Iterable, java.util.Collection

Direct Known Subclasses:

ExtentIndex.ArrayListExtentIndexImpl, ExtentIndex.HashSetExtentIndexImpl

Enclosing interface:

ExtentIndex

public abstract static class ExtentIndex.AbstractExtentIndex
extends java.util.AbstractCollection
implements ExtentIndex

A basic implementation of ExtentIndex that uses Collection-typed buckets. Extending classes must implement #makeBucket(int) to specify an alternative Collection implementation.

Nested Class Summary

Nested classes/interfaces inherited from interface com.bbn.openmap.geo.ExtentIndex

ExtentIndex.AbstractExtentIndex, ExtentIndex.ArrayListExtentIndexImpl, ExtentIndex.HashSetExtentIndexImpl

Field Summary

protected java.util.Collection	all all is a collection of everything successfully indexed.
protected java.util.Collection[]	buckets
static double	D_MARGIN Default value for #margin if not specified in the call to the constructor.
static int	D_NBUCKETS Default value for #nbuckets if not specified in the call to the constructor.
protected java.util.Collection	discarded
double	margin how much of a margin to put around regions for indexing purposes, in nautical miles.
int	nbuckets how many buckets in the longitudinal index - 360 means 1 bucket per degree of longitude.
protected java.util.Collection	polar polar is a bucket for anything that is near enough to either pole to cover more than 1/2 the buckets.

Constructor Summary

ExtentIndex.AbstractExtentIndex()

ExtentIndex.AbstractExtentIndex(double m)

ExtentIndex.AbstractExtentIndex(int nb)

ExtentIndex.AbstractExtentIndex(int nb, double m)

Method Summary

boolean	add(java.lang.Object o) Add an object to the index.
boolean	addExtent(GeoExtent extent) Method to call to add Region object with BoundingCircle to Collection and organize it for later retrieval.
protected int	bucketFor(double lon) figure out what bucket a particular longitude goes in.
void	clear() Method to call to clear out the index.
double	indexHorizontalRange() RegionIndex parameter method.
java.util.Iterator	iterator()
java.util.Iterator	iterator(GeoExtent o) return an iterator listing a subset of the whole collection that is a superset of the actual matches.
protected java.util.Iterator	lookup(double left, double right) Called when you want everything in each bucket between the coordinates.
protected java.util.Iterator	lookup(double left, double right, BoundingCircle bc) Called when you want to get the regions in the buckets, but you want to further filter on objects that can intersect based on the bounding circle provided.
java.util.Iterator	lookupByBoundingCircle(BoundingCircle bc)
java.util.Iterator	lookupByPath(GeoPath path)
java.util.Iterator	lookupBySegment(GeoSegment segment)
protected java.util.Collection	makeBucket()
protected abstract java.util.Collection	makeBucket(int sizeHint) implement to specify the factory to use to create Bucket storage.
protected static double	normalizeLon(double lon) normalize longitude to be at least 0.0 and less than 360 *
protected static double[]	normalizeLons(double[] lons)
boolean	removeExtent(GeoExtent region) Method to call to remove a region from the index.
int	size()
java.lang.String	toString()

Methods inherited from class java.util.AbstractCollection

addAll, contains, containsAll, isEmpty, remove, removeAll, retainAll, toArray, toArray

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface java.util.Collection

addAll, contains, containsAll, equals, hashCode, isEmpty, remove, removeAll, retainAll, toArray, toArray

Field Detail

D_NBUCKETS

public static final int D_NBUCKETS

Default value for #nbuckets if not specified in the call to the constructor.

See Also:

Constant Field Values

D_MARGIN

public static final double D_MARGIN

Default value for #margin if not specified in the call to the constructor.

See Also:

Constant Field Values

nbuckets

public final int nbuckets

how many buckets in the longitudinal index - 360 means 1 bucket per degree of longitude. More than 360 doesn't seem to add much search speed, less than 180 makes it slower. The sweet spot on current datasets is somewhere in between. If unspecified, defaults to #D_NBUCKETS

margin

public final double margin

how much of a margin to put around regions for indexing purposes, in nautical miles. This must be at least the largest margin searched for by route (currently 50nmiles) - the larger this value, the larger the average entries/bucket and so, the slower the search. If unspecified, defaults to #D_MARGIN

buckets

protected final java.util.Collection[] buckets

all

protected final java.util.Collection all

all is a collection of everything successfully indexed.

polar

protected final java.util.Collection polar

polar is a bucket for anything that is near enough to either pole to cover more than 1/2 the buckets.

discarded

protected final java.util.Collection discarded

Constructor Detail

ExtentIndex.AbstractExtentIndex

public ExtentIndex.AbstractExtentIndex()

ExtentIndex.AbstractExtentIndex

public ExtentIndex.AbstractExtentIndex(int nb)

ExtentIndex.AbstractExtentIndex

public ExtentIndex.AbstractExtentIndex(double m)

ExtentIndex.AbstractExtentIndex

public ExtentIndex.AbstractExtentIndex(int nb,
                                       double m)

Method Detail

makeBucket

protected final java.util.Collection makeBucket()

makeBucket

protected abstract java.util.Collection makeBucket(int sizeHint)

implement to specify the factory to use to create Bucket storage.

Parameters:

sizeHint - a guess at the number of elements that are likely to be stored in this bucket or 0 if unknown.

Returns:

A Collection instance suitable for use as a bucket

add

public boolean add(java.lang.Object o)

Add an object to the index.

Specified by:

add in interface java.util.Collection

Overrides:

add in class java.util.AbstractCollection

Returns:

true if object is a GeoExtent and was added.

addExtent

public boolean addExtent(GeoExtent extent)

Method to call to add Region object with BoundingCircle to Collection and organize it for later retrieval.

Specified by:

addExtent in interface ExtentIndex

Parameters:

extent - Region to index

Returns:

true if object added, false if it's been discarded.

normalizeLon

protected static final double normalizeLon(double lon)

normalize longitude to be at least 0.0 and less than 360 *

bucketFor

protected final int bucketFor(double lon)

figure out what bucket a particular longitude goes in.

normalizeLons

protected static final double[] normalizeLons(double[] lons)

lookup

protected java.util.Iterator lookup(double left,
                                    double right)

Called when you want everything in each bucket between the coordinates.

Parameters:

left - left-most (west) bucket value.

right - right-most (east) bucket value.

Returns:

Iterator over regions in buckets that cover range provided.

lookup

protected java.util.Iterator lookup(double left,
                                    double right,
                                    BoundingCircle bc)

Called when you want to get the regions in the buckets, but you want to further filter on objects that can intersect based on the bounding circle provided.

Parameters:

left - left-most (west) bucket value.

right - right-most (east) bucket value.

bc - Bounding circle to do another filter check, if null, everything in a bucket will be returned.

Returns:

Iterator over regions in buckets that cover range provided that intersect with the BoundingCircle (if one is provided).

removeExtent

public boolean removeExtent(GeoExtent region)

Method to call to remove a region from the index.

Specified by:

removeExtent in interface ExtentIndex

Returns:

true if the region was found and removed.

clear

public void clear()

Method to call to clear out the index.

Specified by:

clear in interface ExtentIndex

Specified by:

clear in interface java.util.Collection

Overrides:

clear in class java.util.AbstractCollection

indexHorizontalRange

public double indexHorizontalRange()

RegionIndex parameter method.

Specified by:

indexHorizontalRange in interface ExtentIndex

Returns:

horizontal range in nautical miles for matches.

lookupBySegment

public java.util.Iterator lookupBySegment(GeoSegment segment)

lookupByPath

public java.util.Iterator lookupByPath(GeoPath path)

lookupByBoundingCircle

public java.util.Iterator lookupByBoundingCircle(BoundingCircle bc)

iterator

public java.util.Iterator iterator(GeoExtent o)

Description copied from interface: ExtentIndex

return an iterator listing a subset of the whole collection that is a superset of the actual matches. A valid (but inefficient) implementation would return an iterator over the whole collection. Implementation should match anything that is likely to match - this will generally include, for instance, additional space around the actual segment to accommodate buffer zones around the segment.

Specified by:

iterator in interface ExtentIndex

Returns:

an Iterator over BoundingCircle objects in the Collection where the GExtent may be related to them.

iterator

public java.util.Iterator iterator()

Specified by:

iterator in interface java.lang.Iterable

Specified by:

iterator in interface java.util.Collection

Specified by:

iterator in class java.util.AbstractCollection

Returns:

Iterator over all entries in Collection.

size

public int size()

Specified by:

size in interface java.util.Collection

Specified by:

size in class java.util.AbstractCollection

Returns:

number of all entries in Collection.

toString

public java.lang.String toString()

Overrides:

toString in class java.util.AbstractCollection