blob: c1a6f987b64be49acb7cf40724d4011e4420fa49 [file] [log] [blame]
/*
* Licensed to the Apache Software Foundation (ASF) under one or more contributor license
* agreements. See the NOTICE file distributed with this work for additional information regarding
* copyright ownership. The ASF licenses this file to You under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance with the License. You may obtain a
* copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software distributed under the License
* is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
* or implied. See the License for the specific language governing permissions and limitations under
* the License.
*/
package org.apache.geode.cache.query.internal;
import java.io.DataInput;
import java.io.DataOutput;
import java.io.IOException;
import org.apache.geode.cache.query.QueryService;
import org.apache.geode.cache.query.internal.index.IndexManager;
import org.apache.geode.internal.DataSerializableFixedID;
import org.apache.geode.internal.Version;
/**
* A Token representing null.
*
* @since GemFire cedar
*
*/
public class NullToken implements DataSerializableFixedID, Comparable {
public NullToken() {
Support.assertState(IndexManager.NULL == null, "NULL constant already instantiated");
}
@Override
public int compareTo(Object o) {
// A Null token is equal to other Null token and less than any other object
// except UNDEFINED
if (o.equals(this)) {
return 0;
} else if (o.equals(QueryService.UNDEFINED)) {
return 1;
} else {
return -1;
}
}
@Override
public boolean equals(Object o) {
return o instanceof NullToken;
}
@Override
public int hashCode() {
return NullToken.class.hashCode();
}
@Override
public int getDSFID() {
return NULL_TOKEN;
}
@Override
public void toData(DataOutput out) throws IOException {
}
@Override
public void fromData(DataInput in) throws IOException, ClassNotFoundException {}
@Override
public Version[] getSerializationVersions() {
return null;
}
}