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A module that is everything required to understands Druid Segments
/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package org.apache.druid.collections.spatial.search;
import com.fasterxml.jackson.annotation.JsonCreator;
import com.fasterxml.jackson.annotation.JsonProperty;
import com.google.common.base.Preconditions;
import com.google.common.base.Predicate;
import com.google.common.collect.Iterables;
import org.apache.druid.collections.spatial.ImmutablePoint;
import java.nio.ByteBuffer;
import java.util.Arrays;
/**
*/
public class PolygonBound extends RectangularBound
{
private static final byte CACHE_TYPE_ID = 0x02;
private final float[] abscissa;
private final float[] ordinate;
private PolygonBound(float[] abscissa, float[] ordinate, int limit)
{
super(getMinCoords(abscissa, ordinate), getMaxCoords(abscissa, ordinate), limit);
this.abscissa = abscissa;
this.ordinate = ordinate;
}
private static float[] getMinCoords(float[] abscissa, float[] ordinate)
{
float[] retVal = new float[2];
retVal[0] = abscissa[0];
retVal[1] = ordinate[0];
for (int i = 1; i < abscissa.length; i++) {
if (abscissa[i] < retVal[0]) {
retVal[0] = abscissa[i];
}
if (ordinate[i] < retVal[1]) {
retVal[1] = ordinate[i];
}
}
return retVal;
}
private static float[] getMaxCoords(float[] abscissa, float[] ordinate)
{
float[] retVal = new float[2];
retVal[0] = abscissa[0];
retVal[1] = ordinate[0];
for (int i = 1; i < abscissa.length; i++) {
if (abscissa[i] > retVal[0]) {
retVal[0] = abscissa[i];
}
if (ordinate[i] > retVal[1]) {
retVal[1] = ordinate[i];
}
}
return retVal;
}
/**
* abscissa and ordinate contain the coordinates of polygon.
* abscissa[i] is the horizontal coordinate for the i'th corner of the polygon,
* and ordinate[i] is the vertical coordinate for the i'th corner.
* The polygon must have more than 2 corners, so the length of abscissa or ordinate must be equal or greater than 3.
*
* if the polygon is a rectangular, which corners are {0.0, 0.0}, {0.0, 1.0}, {1.0, 1.0}, {1.0, 0.0},
* the abscissa should be {0.0, 0.0, 1.0, 1.0} and ordinate should be {0.0, 1.0, 1.0, 0.0}
*/
@JsonCreator
public static PolygonBound from(
@JsonProperty("abscissa") float[] abscissa,
@JsonProperty("ordinate") float[] ordinate,
@JsonProperty("limit") int limit
)
{
Preconditions.checkArgument(abscissa.length == ordinate.length); //abscissa and ordinate should be the same length
Preconditions.checkArgument(abscissa.length > 2); //a polygon should have more than 2 corners
return new PolygonBound(abscissa, ordinate, limit);
}
public static PolygonBound from(float[] abscissa, float[] ordinate)
{
return PolygonBound.from(abscissa, ordinate, 0);
}
@JsonProperty
public float[] getOrdinate()
{
return ordinate;
}
@JsonProperty
public float[] getAbscissa()
{
return abscissa;
}
@Override
public boolean contains(float[] coords)
{
int polyCorners = abscissa.length;
int j = polyCorners - 1;
boolean oddNodes = false;
for (int i = 0; i < polyCorners; i++) {
if (abscissa[i] == coords[0] && ordinate[i] == coords[1]) {
return true;
}
if (isPointLayingOnHorizontalBound(i, j, coords)) {
return true;
}
if (between(ordinate[i], ordinate[j], coords[1]) && (abscissa[j] <= coords[0] || abscissa[i] <= coords[0])) {
float intersectionPointX = abscissa[i] + (coords[1] - ordinate[i]) / (ordinate[j] - ordinate[i]) * (abscissa[j] - abscissa[i]);
if (intersectionPointX == coords[0]) {
return true;
} else if (intersectionPointX < coords[0]) {
oddNodes = !oddNodes;
}
}
j = i;
}
return oddNodes;
}
private boolean isPointLayingOnHorizontalBound(int i, int j, float[] coords)
{
return ordinate[i] == ordinate[j] && ordinate[j] == coords[1] && between(abscissa[i], abscissa[j], coords[0]);
}
private static boolean between(float a, float b, float x)
{
if (a <= b) {
return a <= x && x <= b;
} else {
return b <= x && x <= a;
}
}
@Override
public Iterable filter(Iterable points)
{
return Iterables.filter(
points,
new Predicate()
{
@Override
public boolean apply(ImmutablePoint immutablePoint)
{
return contains(immutablePoint.getCoords());
}
}
);
}
@Override
public byte[] getCacheKey()
{
ByteBuffer abscissaBuffer = ByteBuffer.allocate(abscissa.length * Float.BYTES);
abscissaBuffer.asFloatBuffer().put(abscissa);
final byte[] abscissaCacheKey = abscissaBuffer.array();
ByteBuffer ordinateBuffer = ByteBuffer.allocate(ordinate.length * Float.BYTES);
ordinateBuffer.asFloatBuffer().put(ordinate);
final byte[] ordinateCacheKey = ordinateBuffer.array();
final ByteBuffer cacheKey = ByteBuffer
.allocate(1 + abscissaCacheKey.length + ordinateCacheKey.length + Integer.BYTES)
.put(abscissaCacheKey)
.put(ordinateCacheKey)
.putInt(getLimit())
.put(CACHE_TYPE_ID);
return cacheKey.array();
}
@Override
public boolean equals(Object o)
{
if (this == o) {
return true;
}
if (o == null || getClass() != o.getClass()) {
return false;
}
if (!super.equals(o)) {
return false;
}
PolygonBound that = (PolygonBound) o;
return Arrays.equals(abscissa, that.abscissa) &&
Arrays.equals(ordinate, that.ordinate);
}
@Override
public int hashCode()
{
int result = super.hashCode();
result = 31 * result + Arrays.hashCode(abscissa);
result = 31 * result + Arrays.hashCode(ordinate);
return result;
}
}