/*
* 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 java.sql.SQLException;
import org.apache.hadoop.hbase.io.ImmutableBytesWritable;
import org.apache.hadoop.hbase.util.Bytes;
import org.apache.hadoop.io.WritableUtils;
import org.apache.phoenix.exception.SQLExceptionCode;
import org.apache.phoenix.exception.SQLExceptionInfo;
import org.apache.phoenix.expression.visitor.ExpressionVisitor;
import org.apache.phoenix.schema.ColumnModifier;
import org.apache.phoenix.schema.IllegalDataException;
import org.apache.phoenix.schema.PDataType;
import org.apache.phoenix.schema.TypeMismatchException;
import org.apache.phoenix.schema.tuple.Tuple;
import org.apache.phoenix.util.ByteUtil;
import org.apache.phoenix.util.StringUtil;
/**
*
* Accessor for a literal value.
*
*
* @since 0.1
*/
public class LiteralExpression extends BaseTerminalExpression {
public static final LiteralExpression NULL_EXPRESSION = new LiteralExpression(null);
private static final LiteralExpression[] TYPED_NULL_EXPRESSIONS = new LiteralExpression[PDataType.values().length];
static {
for (int i = 0; i < TYPED_NULL_EXPRESSIONS.length; i++) {
TYPED_NULL_EXPRESSIONS[i] = new LiteralExpression(PDataType.values()[i]);
}
}
public static final LiteralExpression FALSE_EXPRESSION = new LiteralExpression(Boolean.FALSE, PDataType.BOOLEAN, PDataType.BOOLEAN.toBytes(Boolean.FALSE));
public static final LiteralExpression TRUE_EXPRESSION = new LiteralExpression(Boolean.TRUE, PDataType.BOOLEAN, PDataType.BOOLEAN.toBytes(Boolean.TRUE));
private Object value;
private PDataType type;
private byte[] byteValue;
private Integer byteSize;
private Integer maxLength;
private Integer scale;
private ColumnModifier columnModifier;
// TODO: cache?
public static LiteralExpression newConstant(Object value) {
if (Boolean.FALSE.equals(value)) {
return FALSE_EXPRESSION;
}
if (Boolean.TRUE.equals(value)) {
return TRUE_EXPRESSION;
}
if (value == null) {
return NULL_EXPRESSION;
}
PDataType type = PDataType.fromLiteral(value);
byte[] b = type.toBytes(value);
if (b.length == 0) {
return TYPED_NULL_EXPRESSIONS[type.ordinal()];
}
if (type == PDataType.VARCHAR) {
String s = (String) value;
if (s.length() == b.length) { // single byte characters only
type = PDataType.CHAR;
}
}
return new LiteralExpression(value, type, b);
}
public static LiteralExpression newConstant(Object value, PDataType type) throws SQLException {
return newConstant(value, type, null);
}
public static LiteralExpression newConstant(Object value, PDataType type, ColumnModifier columnModifier) throws SQLException {
return newConstant(value, type, null, null, columnModifier);
}
public static LiteralExpression newConstant(Object value, PDataType type, Integer maxLength, Integer scale) throws SQLException { // remove?
return newConstant(value, type, maxLength, scale, null);
}
// TODO: cache?
public static LiteralExpression newConstant(Object value, PDataType type, Integer maxLength, Integer scale, ColumnModifier columnModifier)
throws SQLException {
if (value == null) {
if (type == null) {
return NULL_EXPRESSION;
}
return TYPED_NULL_EXPRESSIONS[type.ordinal()];
}
PDataType actualType = PDataType.fromLiteral(value);
if (!actualType.isCoercibleTo(type, value)) {
throw new TypeMismatchException(type, actualType, value.toString());
}
value = type.toObject(value, actualType);
try {
byte[] b = type.toBytes(value, columnModifier);
if (type == PDataType.VARCHAR || type == PDataType.CHAR) {
if (type == PDataType.CHAR && maxLength != null && b.length < maxLength) {
b = StringUtil.padChar(b, maxLength);
} else if (value != null) {
maxLength = ((String)value).length();
}
}
if (b.length == 0) {
return TYPED_NULL_EXPRESSIONS[type.ordinal()];
}
return new LiteralExpression(value, type, b, maxLength, scale, columnModifier);
} catch (IllegalDataException e) {
throw new SQLExceptionInfo.Builder(SQLExceptionCode.ILLEGAL_DATA).setRootCause(e).build().buildException();
}
}
public LiteralExpression() {
}
private LiteralExpression(PDataType type) {
this(null, type, ByteUtil.EMPTY_BYTE_ARRAY);
}
private LiteralExpression(Object value, PDataType type, byte[] byteValue) {
this(value, type, byteValue, type == null? null : type.getMaxLength(value), type == null? null : type.getScale(value), null);
}
private LiteralExpression(Object value, PDataType type, byte[] byteValue,
Integer maxLength, Integer scale, ColumnModifier columnModifier) {
this.value = value;
this.type = type;
this.byteValue = byteValue;
this.byteSize = byteValue.length;
this.maxLength = maxLength;
this.scale = scale;
this.columnModifier = columnModifier;
}
@Override
public String toString() {
return type != null && type.isCoercibleTo(PDataType.VARCHAR) ? "'" + value + "'" : "" + value;
}
@Override
public int hashCode() {
final int prime = 31;
int result = 1;
result = prime * result + ((value == null) ? 0 : value.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;
LiteralExpression other = (LiteralExpression)obj;
if (value == null) {
if (other.value != null) return false;
} else if (!value.equals(other.value)) return false;
return true;
}
@Override
public void readFields(DataInput input) throws IOException {
this.byteValue = Bytes.readByteArray(input);
columnModifier = ColumnModifier.fromSystemValue(WritableUtils.readVInt(input));
if (this.byteValue.length > 0) {
this.type = PDataType.values()[WritableUtils.readVInt(input)];
this.value = this.type.toObject(byteValue, 0, byteValue.length, this.type, columnModifier);
}
byteSize = this.byteValue.length;
}
@Override
public void write(DataOutput output) throws IOException {
Bytes.writeByteArray(output, byteValue);
WritableUtils.writeVInt(output, ColumnModifier.toSystemValue(columnModifier));
if (this.byteValue.length > 0) {
WritableUtils.writeVInt(output, this.type.ordinal());
}
}
@Override
public boolean evaluate(Tuple tuple, ImmutableBytesWritable ptr) {
// Literal always evaluates, even when it returns null
ptr.set(byteValue);
return true;
}
@Override
public PDataType getDataType() {
return type;
}
@Override
public Integer getByteSize() {
return byteSize;
}
@Override
public Integer getMaxLength() {
return maxLength;
}
@Override
public Integer getScale() {
return scale;
}
@Override
public ColumnModifier getColumnModifier() {
return columnModifier;
}
@Override
public boolean isNullable() {
return value == null;
}
public Object getValue() {
return value;
}
public byte[] getBytes() {
return byteValue;
}
@Override
public final <T> T accept(ExpressionVisitor<T> visitor) {
return visitor.visit(this);
}
@Override
public boolean isConstant() {
return true;
}
}