Package org.apache.derby.iapi.types
Class SQLRef
- java.lang.Object
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- org.apache.derby.iapi.types.DataType
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- org.apache.derby.iapi.types.SQLRef
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- 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
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Field Summary
Fields Modifier and Type Field Description private static int
BASE_MEMORY_USAGE
protected RowLocation
value
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Fields inherited from interface org.apache.derby.iapi.types.DataValueDescriptor
UNKNOWN_LOGICAL_LENGTH
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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
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Constructor Summary
Constructors Constructor Description SQLRef()
SQLRef(RowLocation rowLocation)
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description DataValueDescriptor
cloneValue(boolean forceMaterialization)
Clone this DataValueDescriptor.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
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 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 datatypeint
hashCode()
Adding this overload makes it possible to use SQLRefs as keys in HashMaps.boolean
isNull()
Return whether the value is null or not.void
readExternal(java.io.ObjectInput in)
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)
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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, getShort, getStream, getTime, getTimestamp, getTraceString, getTypeName, greaterOrEquals, greaterThan, hasStream, in, invalidFormat, isNotNull, isNullOp, lessOrEquals, lessThan, normalize, notEquals, outOfRange, readExternalFromArray, recycle, setBigDecimal, setInto, setObject, setObjectForCast, setToNull, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, throwLangSetMismatch, throwLangSetMismatch, typePrecedence, typeToBigDecimal
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Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait
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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, readExternalFromArray, recycle, setBigDecimal, setInto, setObjectForCast, setToNull, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, typePrecedence, typeToBigDecimal
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Field Detail
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value
protected RowLocation value
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BASE_MEMORY_USAGE
private static final int BASE_MEMORY_USAGE
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Constructor Detail
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SQLRef
public SQLRef()
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SQLRef
public SQLRef(RowLocation rowLocation)
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Method Detail
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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 interfaceDataValueDescriptor
- Returns:
- the estimated memory usage
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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 interfaceDataValueDescriptor
- Returns:
- The data value as a String.
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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 interfaceDataValueDescriptor
- Overrides:
getObject
in classDataType
- Returns:
- The data value as a int.
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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 classDataType
- Parameters:
theValue
- The DataValueDescriptor that holds the value to which we want to set this DataValueDescriptor's value.- Throws:
StandardException
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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 interfaceDataValueDescriptor
- Returns:
- The length of the data value
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getTypeName
public java.lang.String getTypeName()
Description copied from interface:DataValueDescriptor
Get the SQL name of the datatype- Specified by:
getTypeName
in interfaceDataValueDescriptor
- Returns:
- The SQL name of the datatype
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getTypeFormatId
public int getTypeFormatId()
Return my format identifier.- Specified by:
getTypeFormatId
in interfaceTypedFormat
- Returns:
- The identifier. (A UUID stuffed in an array of 16 bytes).
- See Also:
TypedFormat.getTypeFormatId()
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isNull
public boolean isNull()
Description copied from interface:Storable
Return whether the value is null or not.
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writeExternal
public void writeExternal(java.io.ObjectOutput out) throws java.io.IOException
- Specified by:
writeExternal
in interfacejava.io.Externalizable
- Throws:
java.io.IOException
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readExternal
public void readExternal(java.io.ObjectInput in) throws java.io.IOException, java.lang.ClassNotFoundException
- Specified by:
readExternal
in interfacejava.io.Externalizable
- Throws:
java.io.IOException
- Thrown on error reading the objectjava.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)
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restoreToNull
public void restoreToNull()
Description copied from interface:Storable
Restore this object to its (SQL)null value.- Specified by:
restoreToNull
in interfaceStorable
- See Also:
Storable.restoreToNull()
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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 interfaceDataValueDescriptor
- Overrides:
compare
in classDataType
- 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
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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 interfaceDataValueDescriptor
- 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
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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 ifforceMaterialization
is set tofalse
. An example is if you need to access the value you just read usingcloneValue
after the current transaction has ended, or after the source result set has been closed.- Specified by:
cloneValue
in interfaceDataValueDescriptor
- Parameters:
forceMaterialization
- any streams representing the data value will be materialized iftrue
, the data value will be kept as a stream if possible iffalse
- Returns:
- A clone of the
DataValueDescriptor
with the same initial value as this. - See Also:
DataValueDescriptor.cloneValue(boolean)
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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 interfaceDataValueDescriptor
- See Also:
DataValueDescriptor.getNewNull()
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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 interfaceDataValueDescriptor
- 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)
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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 interfaceDataValueDescriptor
- Overrides:
setInto
in classDataType
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setValue
public void setValue(RowLocation rowLocation)
Description copied from interface:RefDataValue
Set the value of this RefDataValue.- Specified by:
setValue
in interfaceRefDataValue
- Parameters:
rowLocation
- Contains the boolean value to set this RefDataValue to. Null means set this RefDataValue to null.
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toString
public java.lang.String toString()
- Overrides:
toString
in classjava.lang.Object
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hashCode
public int hashCode()
Adding this overload makes it possible to use SQLRefs as keys in HashMaps.- Overrides:
hashCode
in classjava.lang.Object
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