io.debezium.ibmi.db2.journal.retrieve.JournalFileEntryDecoder Maven / Gradle / Ivy
/*
* Copyright Debezium Authors.
*
* Licensed under the Apache Software License version 2.0, available at http://www.apache.org/licenses/LICENSE-2.0
*/
package io.debezium.ibmi.db2.journal.retrieve;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import com.ibm.as400.access.AS400UnsignedBin4;
import io.debezium.ibmi.db2.journal.retrieve.rjne0200.EntryHeader;
public abstract class JournalFileEntryDecoder implements JournalEntryDeocder {
public JournalFileEntryDecoder() {
}
public abstract Object[] decodeFile(EntryHeader entryHeader, byte[] data, int offset) throws Exception;
@Override
public Object[] decode(EntryHeader entryHeader, byte[] data, int offset) throws Exception {
Object[] objs = decodeFile(entryHeader, data, offset);
Object[] nullified = nullify(objs, entryHeader, data, offset);
return nullified;
}
Object[] nullify(Object[] objs, EntryHeader entryHeader, byte[] data, int offset) {
boolean[] isNull = getNullFieldIndicators(data, entryHeader.getNullValueOffest(), offset);
if (isNull == null) {
return objs;
}
else {
int length = Math.min(objs.length, isNull.length);
for (int i = 0; i < length; i++) {
if (isNull[i]) {
objs[i] = null;
}
}
}
return objs;
}
static final Logger log = LoggerFactory.getLogger(JournalEntryDeocder.class);
static final AS400UnsignedBin4 NullIndicatorLengthDecoder = new AS400UnsignedBin4();
private boolean[] getNullFieldIndicators(byte[] data, int nullEntryOffset, int offset) {
boolean[] isNull = null;
if (nullEntryOffset != 0) {
long l = NullIndicatorLengthDecoder.toLong(data, offset + nullEntryOffset);
if (l > Integer.MAX_VALUE) {
log.error("null indicator length unreasonably large {}", l);
return null;
}
int length = (int) l;
isNull = new boolean[length];
for (int i = 0; i < length; i++) {
// BCD bottom 4 bits
isNull[i] = (data[offset + nullEntryOffset + 4 + i] & 15) == 1; // 1 = is null, 0 = not null, 9 = default value returned
}
}
return isNull;
}
}