ZapReleaseComparitor.java

package org.zaproxy.zap.control;

import java.util.Comparator;

import org.parosproxy.paros.Constant;

public class ZapReleaseComparitor implements Comparator<ZapRelease> {

	@Override
	public int compare(ZapRelease zr1, ZapRelease zr2) {
		
		// Null checks
		if (zr1 == null) {
			if (zr2 == null) {
				return 0;
			}
			return 1;
		} else if (zr2 == null) {
			return -1;
		}
		if (zr1.getVersion().equals(zr2.getVersion())) {
			// Exactly the same
			return 0;
		}
		// Special cases
		if (Constant.isDevBuild(zr1.getVersion())) {
			return 1;
		}
		if (Constant.isDevBuild(zr2.getVersion())) {
			return -1;
		}
		if (Constant.isDailyBuild(zr1.getVersion())) {
			if (Constant.isDailyBuild(zr2.getVersion())) {
				// Can just do string comparison
				return zr1.getVersion().compareTo(zr2.getVersion());
			} else {
				// Daily build always trump numbered releases
				return 1;
			}
		}
		if (Constant.isDailyBuild(zr2.getVersion())) {
			// Daily build always trump numbered releases
			return -1;
		}
		
    	String [] zr1Array = zr1.getVersion().split("\\.");
    	String [] zr2Array = zr2.getVersion().split("\\.");

    	for (int i = 0; i < zr1Array.length; i++) {
    		if (i >= zr2Array.length) {
    			// Equal up to now, zr1 longer so more recent (eg 2.0.0.1 is more recent that 2.0.0)
    			return 1;
    		}
    		if (zr1Array[i].equals(zr2Array[i])) {
    			// same elements, carry on to next one
    			continue;
    		}
			Integer zr1Int = null;
			Integer zr2Int = null;
			try {
				zr1Int = Integer.parseInt(zr1Array[i]);
			} catch (NumberFormatException e) {
				// Ignore
			}
			try {
				zr2Int = Integer.parseInt(zr2Array[i]);
			} catch (NumberFormatException e) {
				// Ignore
			}
			if (zr1Int != null) {
				if (zr2Int != null) {
					// both different integer elements
					return zr1Int - zr2Int;
				} else {
					if (zr2Array[i].equals(Constant.ALPHA_VERSION) || zr2Array[i].equals(Constant.BETA_VERSION)) {
						// zr2 element alpha or beta, so before any number (eg 2.0.0 is more recent than 2.0.alpha)
						return 1;
					} else {
						throw new IllegalArgumentException("Invalid release number: " + zr2);
					}
				}
			} else if (zr2Int != null) {
				// zr1 element not a number, zr2 is 
				if (zr1Array[i].equals(Constant.ALPHA_VERSION) || zr1Array[i].equals(Constant.BETA_VERSION)) {
					// zr1 element alpha or beta, so before any number (eg 2.0.0 is more recent than 2.0.alpha)
					return -1;
				} else {
					throw new IllegalArgumentException("Invalid release number: " + zr1.getVersion());
				}
			} else {
				// neither numbers, must be different
				if (zr1Array[i].equals(Constant.ALPHA_VERSION)) {
					return -1;
				} else if (zr1Array[i].equals(Constant.BETA_VERSION)) {
					return +1;
				} else {
					throw new IllegalArgumentException("Invalid release number: " + zr1.getVersion());
				}
			}
    	}
    	// All elements the same, but zr2 longer so more recent  
    	return -1;
	}

}