/** Copyright by Barry G. Becker, 2000-2011. Licensed under MIT License: http://www.opensource.org/licenses/MIT */
package com.barrybecker4.game.twoplayer.go.board.analysis.eye;
import com.barrybecker4.game.twoplayer.go.board.analysis.eye.information.EyeInformation;
import com.barrybecker4.game.twoplayer.go.board.analysis.eye.information.EyeType;
import com.barrybecker4.game.twoplayer.go.board.elements.eye.IGoEye;
import com.barrybecker4.game.twoplayer.go.board.elements.position.GoBoardPosition;
import com.barrybecker4.game.twoplayer.go.board.elements.position.GoBoardPositionSet;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
/**
* Determine properties about a big eye on the board.
* This analyzer is only used by the EyeTypeAnalyzer.
* It classifies eyes that are not false eye and have between 2 and 8 spaces_.
* Some of those spaces_ may have enemy stones in them.
* See EyeTypeAnalyzer
*
* @author Barry Becker
*/
class BigEyeAnalyzer {
/** spaces_ in the eye */
private GoBoardPositionSet spaces_;
/**
* The eye must have between 3 and 8 spaces_.
* @param eye the eye to analyze
*/
BigEyeAnalyzer(IGoEye eye) {
spaces_ = eye.getMembers();
int size = spaces_.size();
assert ( size > 3 && size < 8 );
}
/**
* For some eyes (like big eyes) there are one or more key points that will make a single eye if
* the opponent plays first (or first and second if 2 key points), or 2 eyes if you play first.
* We refer to the paper "When One Eye is Sufficient: A Static Classification"
* to classify the different eye types based solely on eye-point neighbors.
*
* The pattern formed by the sorted list of neighbor counts uniquely determines the type.
*
* @return the eye type determined based on the properties and neighbors of the positions in the spaces_ list.
*/
EyeInformation determineEyeInformation()
{
List<Integer> counts = new ArrayList<Integer>(7);
for (GoBoardPosition space : spaces_) {
counts.add(getNumEyeNobiNeighbors(space));
}
Collections.sort(counts);
return getEyeInformation(counts);
}
private EyeInformation getEyeInformation(List<Integer> counts) {
StringBuilder bldr = new StringBuilder("E");
for (int num : counts) {
bldr.append(num);
}
EyeType type = EyeType.valueOf("E" + counts.size());
return type.getInformation(bldr.toString());
}
/**
* @param space eye space to check
* @return number of eye-space nobi neighbors.
* these neighbors may either be blanks or dead stones of the opponent
*/
private int getNumEyeNobiNeighbors(GoBoardPosition space)
{
int numNbrs = 0;
for (GoBoardPosition eyeSpace : spaces_) {
if ( space.isNeighbor( eyeSpace ))
numNbrs++;
}
return numNbrs;
}
}