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package com.ericsson.ssa.sip.dns;
import org.xbill.DNS.SRVRecord;
import java.util.Comparator;
public class SrvComparator implements Comparator {
private static final int compBEFORE = -1;
private static final int compEQUAL = 0;
private static final int compAFTER = 1;
public SrvComparator() {
}
public int compare(Object o1, Object o2) {
SRVRecord rec1 = (SRVRecord) o1;
SRVRecord rec2 = (SRVRecord) o2;
int comparison = comparePriority(rec1, rec2);
if (comparison != compEQUAL) {
return comparison;
}
comparison = compareWeight(rec1, rec2);
if (comparison != compEQUAL) {
return comparison;
}
// for records which has the same priority&weight
// compare hashcode so the sortorder is allways the same
// otherwise the random distributions of srv records is fucked up
// due to that the caching is decided to be performed in dnsjava
return compareHashCode(rec1, rec2);
}
public int comparePriority(SRVRecord rec1, SRVRecord rec2) {
return ((rec1.getPriority() < rec2.getPriority()) ? compBEFORE
: ((rec1.getPriority() == rec2.getPriority())
? compEQUAL : compAFTER));
}
public int compareWeight(SRVRecord rec1, SRVRecord rec2) {
return ((rec1.getWeight() < rec2.getWeight()) ? compBEFORE
: ((rec1.getWeight() == rec2.getWeight())
? compEQUAL : compAFTER));
}
public int compareHashCode(SRVRecord rec1, SRVRecord rec2) {
return ((rec1.hashCode() < rec2.hashCode()) ? compBEFORE
: ((rec1.hashCode() == rec2.hashCode())
? compEQUAL : compAFTER));
}
public boolean equals(Object obj) {
return equals(obj);
}
}