org.apache.derby.iapi.types
Class SQLRef

java.lang.Object
  extended by org.apache.derby.iapi.types.DataType
      extended by org.apache.derby.iapi.types.SQLRef
All Implemented Interfaces:
java.io.Externalizable, java.io.Serializable, java.lang.Comparable, Formatable, Storable, TypedFormat, DataValueDescriptor, Orderable, RefDataValue

public class SQLRef
extends DataType
implements RefDataValue

See Also:
Serialized Form

Field Summary
private static int BASE_MEMORY_USAGE
           
protected  RowLocation value
           
 
Fields inherited from interface org.apache.derby.iapi.types.DataValueDescriptor
UNKNOWN_LOGICAL_LENGTH
 
Fields inherited from interface org.apache.derby.iapi.types.Orderable
ORDER_OP_EQUALS, ORDER_OP_GREATEROREQUALS, ORDER_OP_GREATERTHAN, ORDER_OP_LESSOREQUALS, ORDER_OP_LESSTHAN
 
Constructor Summary
SQLRef()
           
SQLRef(RowLocation rowLocation)
           
 
Method Summary
 DataValueDescriptor cloneValue(boolean forceMaterialization)
          Clone this DataValueDescriptor.
 int compare(DataValueDescriptor other)
          Compare this Orderable with a given Orderable for the purpose of index positioning.
 boolean compare(int op, DataValueDescriptor other, boolean orderedNulls, boolean unknownRV)
          Compare this Orderable with a given Orderable for the purpose of qualification and sorting.
 int estimateMemoryUsage()
          Estimate the memory usage in bytes of the data value and the overhead of the class.
 int getLength()
          Gets the length of the data value.
 DataValueDescriptor getNewNull()
          Get a new null value of the same type as this data value.
 java.lang.Object getObject()
          Gets the value in the data value descriptor as a int.
 java.lang.String getString()
          Gets the value in the data value descriptor as a String.
 int getTypeFormatId()
          Return my format identifier.
 java.lang.String getTypeName()
          Get the SQL name of the datatype
 boolean isNull()
          Return whether the value is null or not.
 void readExternal(java.io.ObjectInput in)
           
 void readExternalFromArray(ArrayInputStream in)
          Read the DataValueDescriptor from the stream.
 void restoreToNull()
          Restore this object to its (SQL)null value.
protected  void setFrom(DataValueDescriptor theValue)
          Set the value of this DataValueDescriptor based on the value of the specified DataValueDescriptor.
 void setInto(java.sql.PreparedStatement ps, int position)
          Set this value into a PreparedStatement.
 void setValue(RowLocation rowLocation)
          Set the value of this RefDataValue.
 void setValueFromResultSet(java.sql.ResultSet resultSet, int colNumber, boolean isNullable)
          Set the value based on the value for the specified DataValueDescriptor from the specified ResultSet.
 java.lang.String toString()
           
 void writeExternal(java.io.ObjectOutput out)
           
 
Methods inherited from class org.apache.derby.iapi.types.DataType
checkHostVariable, cloneHolder, coalesce, compare, compare, compareTo, dataTypeConversion, equals, equals, flip, genericSetObject, getBoolean, getByte, getBytes, getDate, getDouble, getFloat, getInt, getLong, getNationalString, getShort, getStream, getTime, getTimestamp, getTraceString, getTypeName, greaterOrEquals, greaterThan, hasStream, in, invalidFormat, isNotNull, isNullOp, lessOrEquals, lessThan, normalize, notEquals, outOfRange, recycle, setBigDecimal, setInto, setObject, setObjectForCast, setToNull, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, throwLangSetMismatch, throwLangSetMismatch, typePrecedence, typeToBigDecimal
 
Methods inherited from class java.lang.Object
clone, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
 
Methods inherited from interface org.apache.derby.iapi.types.DataValueDescriptor
checkHostVariable, cloneHolder, coalesce, compare, compare, equals, getBoolean, getByte, getBytes, getDate, getDouble, getFloat, getInt, getLong, getShort, getStream, getTime, getTimestamp, getTraceString, greaterOrEquals, greaterThan, hasStream, in, isNotNull, isNullOp, lessOrEquals, lessThan, normalize, notEquals, recycle, setBigDecimal, setInto, setObjectForCast, setToNull, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, typePrecedence, typeToBigDecimal
 

Field Detail

value

protected RowLocation value

BASE_MEMORY_USAGE

private static final int BASE_MEMORY_USAGE
Constructor Detail

SQLRef

public SQLRef()

SQLRef

public SQLRef(RowLocation rowLocation)
Method Detail

estimateMemoryUsage

public int estimateMemoryUsage()
Description copied from interface: DataValueDescriptor
Estimate the memory usage in bytes of the data value and the overhead of the class.

Specified by:
estimateMemoryUsage in interface DataValueDescriptor
Returns:
the estimated memory usage

getString

public java.lang.String getString()
Description copied from interface: DataValueDescriptor
Gets the value in the data value descriptor as a String. Throws an exception if the data value is not a string.

Specified by:
getString in interface DataValueDescriptor
Returns:
The data value as a String.

getObject

public java.lang.Object getObject()
Description copied from class: DataType
Gets the value in the data value descriptor as a int. Throws an exception if the data value is not receivable as a int.

Specified by:
getObject in interface DataValueDescriptor
Overrides:
getObject in class DataType
Returns:
The data value as a int.

setFrom

protected void setFrom(DataValueDescriptor theValue)
                throws StandardException
Description copied from class: DataType
Set the value of this DataValueDescriptor based on the value of the specified DataValueDescriptor.

Overrides:
setFrom in class DataType
Parameters:
theValue - The DataValueDescriptor that holds the value to which we want to set this DataValueDescriptor's value.
Throws:
StandardException

getLength

public int getLength()
Description copied from interface: DataValueDescriptor
Gets the length of the data value. The meaning of this is implementation-dependent. For string types, it is the number of characters in the string. For numeric types, it is the number of bytes used to store the number. This is the actual length of this value, not the length of the type it was defined as. For example, a VARCHAR value may be shorter than the declared VARCHAR (maximum) length.

Specified by:
getLength in interface DataValueDescriptor
Returns:
The length of the data value

getTypeName

public java.lang.String getTypeName()
Description copied from interface: DataValueDescriptor
Get the SQL name of the datatype

Specified by:
getTypeName in interface DataValueDescriptor
Returns:
The SQL name of the datatype

getTypeFormatId

public int getTypeFormatId()
Return my format identifier.

Specified by:
getTypeFormatId in interface TypedFormat
Returns:
The identifier. (A UUID stuffed in an array of 16 bytes).
See Also:
TypedFormat.getTypeFormatId()

isNull

public boolean isNull()
Description copied from interface: Storable
Return whether the value is null or not.

Specified by:
isNull in interface Storable
Returns:
true if the value is null and false otherwise.

writeExternal

public void writeExternal(java.io.ObjectOutput out)
                   throws java.io.IOException
Specified by:
writeExternal in interface java.io.Externalizable
Throws:
java.io.IOException

readExternal

public void readExternal(java.io.ObjectInput in)
                  throws java.io.IOException,
                         java.lang.ClassNotFoundException
Specified by:
readExternal in interface java.io.Externalizable
Throws:
java.io.IOException - Thrown on error reading the object
java.lang.ClassNotFoundException - Thrown if the class of the object read from the stream can't be found (not likely, since it's supposed to be SQLRef).
See Also:
Externalizable.readExternal(java.io.ObjectInput)

readExternalFromArray

public void readExternalFromArray(ArrayInputStream in)
                           throws java.io.IOException,
                                  java.lang.ClassNotFoundException
Description copied from interface: DataValueDescriptor
Read the DataValueDescriptor from the stream.

Initialize the data value by reading it's values from the ArrayInputStream. This interface is provided as a way to achieve possible performance enhancement when reading an array can be optimized over reading from a generic stream from readExternal().

Specified by:
readExternalFromArray in interface DataValueDescriptor
Parameters:
in - The array stream positioned at the beginning of the byte stream to read from.
Throws:
java.io.IOException - Usual error is if you try to read past limit on the stream.
java.lang.ClassNotFoundException - If a necessary class can not be found while reading the object from the stream.

restoreToNull

public void restoreToNull()
Description copied from interface: Storable
Restore this object to its (SQL)null value.

Specified by:
restoreToNull in interface Storable
See Also:
Storable.restoreToNull()

compare

public boolean compare(int op,
                       DataValueDescriptor other,
                       boolean orderedNulls,
                       boolean unknownRV)
                throws StandardException
Description copied from interface: DataValueDescriptor
Compare this Orderable with a given Orderable for the purpose of qualification and sorting. The caller gets to determine how nulls should be treated - they can either be ordered values or unknown values.

Specified by:
compare in interface DataValueDescriptor
Overrides:
compare in class DataType
Parameters:
op - Orderable.ORDER_OP_EQUALS means do an = comparison. Orderable.ORDER_OP_LESSTHAN means compare this < other. Orderable.ORDER_OP_LESSOREQUALS means compare this <= other.
other - The DataValueDescriptor to compare this one to.
orderedNulls - True means to treat nulls as ordered values, that is, treat SQL null as equal to null, and less than all other values. False means to treat nulls as unknown values, that is, the result of any comparison with a null is the UNKNOWN truth value.
unknownRV - The return value to use if the result of the comparison is the UNKNOWN truth value. In other words, if orderedNulls is false, and a null is involved in the comparison, return unknownRV. This parameter is not used orderedNulls is true.
Returns:
true if the comparison is true (duh!)
Throws:
StandardException - Thrown on error

compare

public int compare(DataValueDescriptor other)
            throws StandardException
Description copied from interface: DataValueDescriptor
Compare this Orderable with a given Orderable for the purpose of index positioning. This method treats nulls as ordered values - that is, it treats SQL null as equal to null and greater than all other values.

Specified by:
compare in interface DataValueDescriptor
Parameters:
other - The Orderable to compare this one to.
Returns:
<0 - this Orderable is less than other. 0 - this Orderable equals other. >0 - this Orderable is greater than other. The code should not explicitly look for -1, or 1.
Throws:
StandardException - Thrown on error

cloneValue

public DataValueDescriptor cloneValue(boolean forceMaterialization)
Description copied from interface: DataValueDescriptor
Clone this DataValueDescriptor. Results in a new object that has the same value as this but can be modified independently.

Even though the objects can be modified independently regardless of the value of forceMaterialization, both the clone and the original may be dependent on the store state if forceMaterialization is set to false. An example is if you need to access the value you just read using cloneValue after the current transaction has ended, or after the source result set has been closed.

Specified by:
cloneValue in interface DataValueDescriptor
Parameters:
forceMaterialization - any streams representing the data value will be materialized if true, the data value will be kept as a stream if possible if false
Returns:
A clone of the DataValueDescriptor with the same initial value as this.
See Also:
DataValueDescriptor.cloneValue(boolean)

getNewNull

public DataValueDescriptor getNewNull()
Description copied from interface: DataValueDescriptor
Get a new null value of the same type as this data value.

Specified by:
getNewNull in interface DataValueDescriptor
See Also:
DataValueDescriptor.getNewNull()

setValueFromResultSet

public void setValueFromResultSet(java.sql.ResultSet resultSet,
                                  int colNumber,
                                  boolean isNullable)
Description copied from interface: DataValueDescriptor
Set the value based on the value for the specified DataValueDescriptor from the specified ResultSet.

Specified by:
setValueFromResultSet in interface DataValueDescriptor
Parameters:
resultSet - The specified ResultSet.
colNumber - The 1-based column # into the resultSet.
isNullable - Whether or not the column is nullable (No need to call wasNull() if not)
See Also:
DataValueDescriptor.setValueFromResultSet(java.sql.ResultSet, int, boolean)

setInto

public void setInto(java.sql.PreparedStatement ps,
                    int position)
Description copied from interface: DataValueDescriptor
Set this value into a PreparedStatement. This method must handle setting NULL into the PreparedStatement.

Specified by:
setInto in interface DataValueDescriptor
Overrides:
setInto in class DataType

setValue

public void setValue(RowLocation rowLocation)
Description copied from interface: RefDataValue
Set the value of this RefDataValue.

Specified by:
setValue in interface RefDataValue
Parameters:
rowLocation - Contains the boolean value to set this RefDataValue to. Null means set this RefDataValue to null.

toString

public java.lang.String toString()
Overrides:
toString in class java.lang.Object

Built on Thu 2011-03-10 11:54:14+0000, from revision ???

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