package org.apache.ibatis.cache;
import java.util.ArrayList;
import java.util.List;
public class CacheKey {
public static final CacheKey NULL_CACHE_KEY = new CacheKey();
private static final int DEFAULT_MULTIPLYER = 37;
private static final int DEFAULT_HASHCODE = 17;
private int multiplier;
private int hashcode;
private long checksum;
private int count;
private List updateList;
public CacheKey() {
this.hashcode = DEFAULT_HASHCODE;
this.multiplier = DEFAULT_MULTIPLYER;
this.count = 0;
this.updateList = new ArrayList();
}
public CacheKey(Object[] objects) {
this();
updateAll(objects);
}
public int getUpdateCount() {
return updateList.size();
}
public void update(Object object) {
int baseHashCode = object == null ? 1 : object.hashCode();
count++;
checksum += baseHashCode;
baseHashCode *= count;
hashcode = multiplier * hashcode + baseHashCode;
updateList.add(object);
}
public void updateAll(Object[] objects) {
for (Object o : objects) {
update(o);
}
}
public boolean equals(Object object) {
if (this == object) return true;
if (!(object instanceof CacheKey)) return false;
final CacheKey cacheKey = (CacheKey) object;
if (hashcode != cacheKey.hashcode) return false;
if (checksum != cacheKey.checksum) return false;
if (count != cacheKey.count) return false;
for (int i = 0; i < updateList.size(); i++) {
Object thisObject = updateList.get(i);
Object thatObject = cacheKey.updateList.get(i);
if (thisObject == null) {
if (thatObject != null) return false;
} else {
if (!thisObject.equals(thatObject)) return false;
}
}
return true;
}
public int hashCode() {
return hashcode;
}
public String toString() {
StringBuffer returnValue = new StringBuffer().append(hashcode).append(':').append(checksum);
for (int i = 0; i < updateList.size(); i++) {
returnValue.append(':').append(updateList.get(i));
}
return returnValue.toString();
}
}
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