org.apache.derby.impl.store.access
Class StorableFormatId

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

public class StorableFormatId
extends DataType

See Also:
Serialized Form

Field Summary
private static int BASE_MEMORY_USAGE
           
private  int format_id
           
 
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
StorableFormatId()
           
StorableFormatId(int value)
           
 
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.
 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 Java Object.
 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
 int getValue()
           
 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 from another.
 void setValue(int input_value)
          Set the value of this DataValueDescriptor to the given int value At DataType level just throws an error lower classes will override
 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.
 void writeExternal(java.io.ObjectOutput out)
           
 
Methods inherited from class org.apache.derby.iapi.types.DataType
checkHostVariable, cloneHolder, coalesce, compare, compare, compare, compareTo, dataTypeConversion, equals, equals, flip, getBoolean, getByte, getBytes, getDate, getDouble, getFloat, getInt, getLong, getNationalString, getShort, getStream, getTime, getTimestamp, getTraceString, greaterOrEquals, greaterThan, hasStream, in, invalidFormat, isNotNull, isNullOp, lessOrEquals, lessThan, normalize, notEquals, outOfRange, recycle, setBigDecimal, setInto, setInto, setObjectForCast, setToNull, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, throwLangSetMismatch, typePrecedence, typeToBigDecimal
 
Methods inherited from class java.lang.Object
clone, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

format_id

private int format_id

BASE_MEMORY_USAGE

private static final int BASE_MEMORY_USAGE
Constructor Detail

StorableFormatId

public StorableFormatId()

StorableFormatId

public StorableFormatId(int value)
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.

Returns:
the estimated memory usage

getValue

public int getValue()

setValue

public void setValue(int input_value)
Description copied from class: DataType
Set the value of this DataValueDescriptor to the given int value At DataType level just throws an error lower classes will override

Specified by:
setValue in interface DataValueDescriptor
Overrides:
setValue in class DataType
Parameters:
input_value - The value to set this DataValueDescriptor to

getTypeFormatId

public int getTypeFormatId()
Return my format identifier.

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.

Returns:
true if the value is null and false otherwise.

writeExternal

public void writeExternal(java.io.ObjectOutput out)
                   throws java.io.IOException
Throws:
java.io.IOException

readExternal

public void readExternal(java.io.ObjectInput in)
                  throws java.io.IOException
Throws:
java.io.IOException
See Also:
Externalizable.readExternal(java.io.ObjectInput)

readExternalFromArray

public void readExternalFromArray(ArrayInputStream in)
                           throws java.io.IOException
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().

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.

restoreToNull

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


getLength

public int getLength()
              throws StandardException
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.

Returns:
The length of the data value
Throws:
StandardException - On error
See Also:
DataValueDescriptor.getLength()

getString

public java.lang.String getString()
                           throws StandardException
Gets the value in the data value descriptor as a String. Throws an exception if the data value is not a string.

Returns:
The data value as a String.
Throws:
StandardException - Thrown on error
See Also:
DataValueDescriptor.getString()

getObject

public java.lang.Object getObject()
                           throws StandardException
Gets the value in the data value descriptor as a Java Object. The type of the Object will be the Java object type corresponding to the data value's SQL type. JDBC defines a mapping between Java object types and SQL types - we will allow that to be extended through user type definitions. Throws an exception if the data value is not an object (yeah, right).

Specified by:
getObject in interface DataValueDescriptor
Overrides:
getObject in class DataType
Returns:
The data value as an Object.
Throws:
StandardException - Thrown on error
See Also:
DataValueDescriptor.getObject()

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.

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()
Get a new null value of the same type as this data value.

See Also:
DataValueDescriptor.getNewNull()

setValueFromResultSet

public void setValueFromResultSet(java.sql.ResultSet resultSet,
                                  int colNumber,
                                  boolean isNullable)
                           throws StandardException,
                                  java.sql.SQLException
Set the value based on the value for the specified DataValueDescriptor from the specified ResultSet.

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)
Throws:
StandardException - Thrown on error
java.sql.SQLException - Error accessing the result set
See Also:
DataValueDescriptor.setValueFromResultSet(java.sql.ResultSet, int, boolean)

setFrom

protected void setFrom(DataValueDescriptor theValue)
                throws StandardException
Set the value of this DataValueDescriptor from another.

Overrides:
setFrom in class DataType
Parameters:
theValue - The Date value to set this DataValueDescriptor to
Throws:
StandardException
See Also:
DataValueDescriptor.setValue(int)

getTypeName

public java.lang.String getTypeName()
Get the SQL name of the datatype

Returns:
The SQL name of the datatype
See Also:
DataValueDescriptor.getTypeName()

compare

public int compare(DataValueDescriptor other)
            throws StandardException
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 less than all other values.

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
See Also:
DataValueDescriptor.compare(org.apache.derby.iapi.types.DataValueDescriptor)

Built on Thu 2012-03-29 21:53:33+0000, from revision ???

Apache Derby V10.6 Internals - Copyright © 2004,2007 The Apache Software Foundation. All Rights Reserved.