org.meeuw.i18n.openlocationcode.OpenLocationProvider Maven / Gradle / Ivy
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Provides open location code areas as region objects
package org.meeuw.i18n.openlocationcode;
import java.util.*;
import java.util.function.Consumer;
import java.util.logging.Level;
import java.util.logging.Logger;
import java.util.stream.Stream;
import java.util.stream.StreamSupport;
import javax.annotation.Priority;
import javax.validation.constraints.Min;
import org.checkerframework.checker.nullness.qual.NonNull;
import org.checkerframework.checker.nullness.qual.Nullable;
import org.meeuw.i18n.regions.spi.RegionProvider;
import com.google.openlocationcode.OpenLocationCode;
import static com.google.openlocationcode.OpenLocationCode.*;
/**
* @author Michiel Meeuwissen
* @since 0.1
*/
@Priority(100)
public class OpenLocationProvider implements RegionProvider {
private static final Logger logger = Logger.getLogger(OpenLocationProvider.class.getName());
public static final int CODE_ALPHABET_LENGTH = CODE_ALPHABET.length();
public static final int CODE_ALPHABET_LENGTH_2 = CODE_ALPHABET_LENGTH * CODE_ALPHABET_LENGTH;
/**
* Returns the max length of the {@link OpenLocationCode}s returned by {@link #values()}. The length is defined as the number of pairs of longitude/lattidue digits.
*
* So this value is never negative, but may be odd.
*
* The default is {@code 4}, resulting in codes exactly ending in {@link OpenLocationCode#SEPARATOR}, which are rectangles the size of a block of houses or so, which results in 10_445_954_562 regions coming from {@link #values()}
*/
public static int getMaxLength() {
return maxLength;
}
public static void setMaxLength(int maxLength) {
OpenLocationProvider.maxLength = maxLength;
}
private static @Min(value = 0) int maxLength = 4;
@Override
public Optional getByCode(@NonNull String code, boolean lenient) {
try {
return Optional.of(new OpenLocation(new OpenLocationCode(code)));
} catch (IllegalArgumentException iae) {
return Optional.empty();
}
}
public OpenLocation getByCoordinates(double latitude, double longitude) {
return new OpenLocation(new OpenLocationCode(latitude, longitude));
}
@Override
public Class getProvidedClass() {
return OpenLocation.class;
}
/**
* Returns all possible open location regions. This is a giant list.
*
* It will start with the biggest regions, and incrementally outputs all smaller ones.
*
* You may want to limit using {@link #limitForLength(int)}
*/
@Override
public Stream values() {
return StreamSupport.stream(OpenLocationCodeSpliterator::new, OpenLocationCodeSpliterator.CHARACTERISTICS, false).map(a -> new OpenLocation(toCode(a)));
}
/**
* How much codes will be generated until code of length.
*
* This can be used as a {@link Stream#limit(long)} on {@link #values()} to stop streaming when all codes of the given length have been processed.
* @param length
* @return
*/
public static long limitForLength(@Min(value = 0) int length) {
if (length == 0) {
return 0;
}
long result = 9 * 18;
for (int i = 1; i < length; i++) {
result *= CODE_ALPHABET_LENGTH_2;
}
return result + limitForLength(length - 1);
}
@Override
public String toString() {
return getClass().getSimpleName() + " (" + limitForLength(maxLength) + " codes in stream)";
}
static OpenLocationCode toCode(int[] template) {
StringBuilder builder = new StringBuilder();
for (int i = 0; i <= template.length / 2 - 1; i++) {
builder.append(CODE_ALPHABET.charAt(template[2 * i]));
builder.append(CODE_ALPHABET.charAt(template[2 * i + 1]));
if (builder.length() == 8) {
builder.append(SEPARATOR);
}
}
while (builder.length() < 8) {
builder.append(PADDING_CHARACTER);
}
if (builder.length() == 8) {
builder.append(SEPARATOR);
}
return new OpenLocationCode(builder.toString());
}
static int[] templateAt(long position) {
long numberShorter = 9 * 18;
long proposal = numberShorter;
int length = 2;
while (position > proposal) {
numberShorter = proposal;
proposal = numberShorter + CODE_ALPHABET_LENGTH_2 * numberShorter;
length +=2;
}
long positionRelative = position - numberShorter;
int[] template = new int[length];
fillTemplate(template, positionRelative);
return template;
}
static void fillTemplate(int[] template, long position) {
int i = template.length - 1;
while (i >= 0) {
int max = getMax(i);
int modulo = (int) (position % max);
template[i] = modulo;
position -= modulo;
position /= max;
i--;
}
}
static int[] advance(int[] template, int step, Consumer initter) {
int i = template.length - 1;
while(i >= 0) {
int max = getMax(i);
int newValue = (template[i] + step);
template[i] = newValue % max;
int carry = newValue / max;
if (carry > 0) {
step = carry;
i--;
} else {
return template;
}
}
template = new int[template.length + 2];
initter.accept(template);
return template;
}
static void advance(int[] template, int step) {
advance(template, step, (t) -> {throw new IllegalStateException();});
}
private static int getMax(int positionInTemplate) {
if (positionInTemplate == 0) {
// First latitude character can only have first 9 values.
return 9;
} else if (positionInTemplate == 1) {
// First longitude character can only have first 18 values.
return 18;
} else {
return CODE_ALPHABET_LENGTH;
}
}
static long position(int[] template) {
int factor = 1;
int result = 0;
int i = template.length - 1;
while (i >= 0) {
int nextExtraFactor = getMax(i);
result += template[i] * factor;
factor *= nextExtraFactor;
i--;
}
return result;
}
private static class OpenLocationCodeSpliterator implements Spliterator {
static final int CHARACTERISTICS = DISTINCT | NONNULL | IMMUTABLE;
static final int maxStep;
static {
int availableProcessors = Runtime.getRuntime().availableProcessors();
maxStep = Math.min(availableProcessors, 8);
}
long count = 0;
int[] template = new int[2];
long lastCount = limitForLength(maxLength);
int step = 1;
int loggedAtStep = -1;
int offset = 0;
@Override
public boolean tryAdvance(Consumer action) {
if (count > lastCount) {
return false;
}
if (logger.isLoggable(Level.FINE) && loggedAtStep != step) {
logger.fine("Running in " + Thread.currentThread().getName() + " step: " + step + " offset: " + offset);
loggedAtStep = step;
}
action.accept(template);
template = advance(template, step, (t) -> advance(t, offset));
if (template.length / 2 > maxLength) {
return false;
}
count++;
return true;
}
@Override
@SuppressWarnings("override.return.invalid") // Checker forgot to annotate Spliterator
@Nullable
public Spliterator trySplit() {
// split will result in the current spliterator handling the even ones, and the split of one the odd ones
OpenLocationCodeSpliterator split = new OpenLocationCodeSpliterator();
if (step >= maxStep) {
// having it bigger will result so much threads that it doesn't increase performance
return null;
}
split.lastCount = lastCount;
split.template = new int[template.length];
System.arraycopy(template, 0, split.template, 0, template.length);
split.offset = offset + step;
split.template = advance(split.template, step, t -> advance(split.template, split.offset));
step *= 2;
split.step = step;
split.count = count;
return split;
}
@Override
public long estimateSize() {
return (lastCount - count) / step;
}
@Override
public Comparator getComparator() {
return new Comparator() {
@Override
public int compare(int[] a, int[] b) {
if (a == b) {
return 0;
}
int i = 0;
int max = Math.min(a.length, b.length);
while (i < max) {
if (a[i] != b[i]) {
return Integer.compare(a[i], b[i]);
}
i++;
}
return a.length - b.length;
}
};
}
@Override
public int characteristics() {
return step == 1 ? CHARACTERISTICS | SIZED : CHARACTERISTICS;
}
}
}
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