/*
* 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.phoenix.expression;
import java.io.DataInput;
import java.io.DataOutput;
import java.io.IOException;
import org.apache.hadoop.io.WritableUtils;
import org.apache.phoenix.schema.PDataType;
import org.apache.phoenix.schema.PDatum;
import org.apache.phoenix.schema.SortOrder;
/**
*
* Common base class for column value accessors
*
*
* @since 0.1
*/
abstract public class ColumnExpression extends BaseTerminalExpression {
protected PDataType type;
private boolean isNullable;
private Integer maxLength;
private Integer scale;
private SortOrder sortOrder;
public ColumnExpression() {
}
// TODO: review, as the hashCode() and equals() here seem unnecessary
@Override
public int hashCode() {
final int prime = 31;
int result = 1;
result = prime * result + (isNullable() ? 1231 : 1237);
PDataType type = this.getDataType();
result = prime * result + ((type == null) ? 0 : type.hashCode());
return result;
}
@Override
public boolean equals(Object obj) {
if (this == obj) return true;
if (obj == null) return false;
if (getClass() != obj.getClass()) return false;
ColumnExpression other = (ColumnExpression)obj;
if (this.isNullable() != other.isNullable()) return false;
if (this.getDataType() != other.getDataType()) return false;
return true;
}
public ColumnExpression(PDatum datum) {
this.type = datum.getDataType();
this.isNullable = datum.isNullable();
this.maxLength = datum.getMaxLength();
this.scale = datum.getScale();
this.sortOrder = datum.getSortOrder();
}
@Override
public boolean isNullable() {
return isNullable;
}
@Override
public PDataType getDataType() {
return type;
}
@Override
public SortOrder getSortOrder() {
return sortOrder;
}
@Override
public Integer getMaxLength() {
return maxLength;
}
@Override
public Integer getScale() {
return scale;
}
@Override
public void readFields(DataInput input) throws IOException {
// read/write type ordinal, maxLength presence, scale presence and isNullable bit together to save space
int typeAndFlag = WritableUtils.readVInt(input);
isNullable = (typeAndFlag & 0x01) != 0;
if ((typeAndFlag & 0x02) != 0) {
scale = WritableUtils.readVInt(input);
}
if ((typeAndFlag & 0x04) != 0) {
maxLength = WritableUtils.readVInt(input);
}
type = PDataType.values()[typeAndFlag >>> 3];
sortOrder = SortOrder.fromSystemValue(WritableUtils.readVInt(input));
}
@Override
public void write(DataOutput output) throws IOException {
// read/write type ordinal, maxLength presence, scale presence and isNullable bit together to save space
int typeAndFlag = (isNullable ? 1 : 0) | ((scale != null ? 1 : 0) << 1) | ((maxLength != null ? 1 : 0) << 2)
| (type.ordinal() << 3);
WritableUtils.writeVInt(output,typeAndFlag);
if (scale != null) {
WritableUtils.writeVInt(output, scale);
}
if (maxLength != null) {
WritableUtils.writeVInt(output, maxLength);
}
WritableUtils.writeVInt(output, sortOrder.getSystemValue());
}
}