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package com.salesforce.phoenix.expression.function;
import java.io.*;
import java.sql.SQLException;
import java.text.Format;
import java.util.List;
import org.apache.hadoop.hbase.io.ImmutableBytesWritable;
import org.apache.hadoop.io.WritableUtils;
import com.google.common.base.Preconditions;
import com.salesforce.phoenix.expression.Expression;
import com.salesforce.phoenix.parse.FunctionParseNode.Argument;
import com.salesforce.phoenix.parse.FunctionParseNode.BuiltInFunction;
import com.salesforce.phoenix.parse.*;
import com.salesforce.phoenix.schema.PDataType;
import com.salesforce.phoenix.schema.tuple.Tuple;
/**
*
* Implementation of the TO_CHAR(<date>/<number>,[<format-string>] built-in function.
* The first argument must be of type DATE or TIME or TIMESTAMP or DECIMAL or INTEGER, and the second argument must be a constant string.
*
* @author jtaylor
* @since 0.1
*/
@BuiltInFunction(name=ToCharFunction.NAME, nodeClass=ToCharParseNode.class, args={
@Argument(allowedTypes={PDataType.TIMESTAMP, PDataType.DECIMAL}),
@Argument(allowedTypes={PDataType.VARCHAR},isConstant=true,defaultValue="null") } )
public class ToCharFunction extends ScalarFunction {
public static final String NAME = "TO_CHAR";
private String formatString;
private Format formatter;
private FunctionArgumentType type;
public ToCharFunction() {
}
public ToCharFunction(List<Expression> children, FunctionArgumentType type, String formatString, Format formatter) throws SQLException {
super(children.subList(0, 1));
Preconditions.checkNotNull(formatString);
Preconditions.checkNotNull(formatter);
Preconditions.checkNotNull(type);
this.type = type;
this.formatString = formatString;
this.formatter = formatter;
}
@Override
public int hashCode() {
final int prime = 31;
int result = 1;
result = prime * result + formatString.hashCode();
result = prime * result + getExpression().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;
ToCharFunction other = (ToCharFunction)obj;
if (!getExpression().equals(other.getExpression())) return false;
if (!formatString.equals(other.formatString)) return false;
return true;
}
@Override
public boolean evaluate(Tuple tuple, ImmutableBytesWritable ptr) {
Expression expression = getExpression();
if (!expression.evaluate(tuple, ptr)) {
return false;
}
PDataType type = expression.getDataType();
Object value = formatter.format(type.toObject(ptr, expression.getColumnModifier()));
byte[] b = getDataType().toBytes(value);
ptr.set(b);
return true;
}
@Override
public PDataType getDataType() {
return PDataType.VARCHAR;
}
@Override
public boolean isNullable() {
return getExpression().isNullable();
}
@Override
public void readFields(DataInput input) throws IOException {
super.readFields(input);
formatString = WritableUtils.readString(input);
type = WritableUtils.readEnum(input, FunctionArgumentType.class);
formatter = type.getFormatter(formatString);
}
@Override
public void write(DataOutput output) throws IOException {
super.write(output);
WritableUtils.writeString(output, formatString);
WritableUtils.writeEnum(output, type);
}
private Expression getExpression() {
return children.get(0);
}
@Override
public String getName() {
return NAME;
}
}