Class HeapRowLocation
- java.lang.Object
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- org.apache.derby.iapi.types.DataType
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- org.apache.derby.impl.store.access.heap.HeapRowLocation
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- All Implemented Interfaces:
java.io.Externalizable
,java.io.Serializable
,java.lang.Comparable
,Formatable
,Storable
,TypedFormat
,DataValueDescriptor
,Orderable
,RefDataValue
,RowLocation
public class HeapRowLocation extends DataType implements RowLocation, RefDataValue
A heap row location represents the location of a row in the heap.It is implementad as a wrapper around a raw store record handle.
- See Also:
- Serialized Form
Format ID ACCESS_HEAP_ROW_LOCATION_V1_ID Purpose Object used to store the location of a row within a Heap table. One of these is stored in every row of a btree secondary index built on a heap base table. Upgrade The type of the btree determines the type of rowlocation stored. In current btree implementations only one type of rowlocation can be stored per tree, and it's type is stored in the format id array stored in the Conglomerate object. Disk Layout page number(CompressedNumber.writeLong()) record id(CompressedNumber.writeInt())
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Field Summary
Fields Modifier and Type Field Description private static int
BASE_MEMORY_USAGE
private long
pageno
The HeapRowLocation simply maintains a raw store record handle.private int
recid
private static int
RECORD_HANDLE_MEMORY_USAGE
private RecordHandle
rh
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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 Modifier Constructor Description HeapRowLocation()
(package private)
HeapRowLocation(RecordHandle rh)
private
HeapRowLocation(HeapRowLocation other)
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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.boolean
equals(java.lang.Object ref)
Implement value equality.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.RecordHandle
getRecordHandle(ContainerHandle ch)
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()
Return a hashcode based on value.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.DataValueDescriptor
recycle()
Recycle this HeapRowLocation object.void
restoreToNull()
Restore this object to its (SQL)null value.(package private) void
setFrom(RecordHandle rh)
protected void
setFrom(DataValueDescriptor theValue)
Set the value of this DataValueDescriptor based on the value of the specified DataValueDescriptor.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, flip, getBoolean, getByte, getBytes, getDate, getDouble, getFloat, getInt, getLong, getShort, getStream, getTime, getTimestamp, getTraceString, greaterOrEquals, greaterThan, hasStream, in, invalidFormat, isNotNull, isNullOp, lessOrEquals, lessThan, normalize, notEquals, outOfRange, setBigDecimal, setInto, setInto, setObjectForCast, setToNull, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, 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, setBigDecimal, setInto, 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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pageno
private long pageno
The HeapRowLocation simply maintains a raw store record handle.
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recid
private int recid
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rh
private RecordHandle rh
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BASE_MEMORY_USAGE
private static final int BASE_MEMORY_USAGE
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RECORD_HANDLE_MEMORY_USAGE
private static final int RECORD_HANDLE_MEMORY_USAGE
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Constructor Detail
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HeapRowLocation
HeapRowLocation(RecordHandle rh)
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HeapRowLocation
public HeapRowLocation()
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HeapRowLocation
private HeapRowLocation(HeapRowLocation other)
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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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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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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)
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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
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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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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.
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recycle
public DataValueDescriptor recycle()
Recycle this HeapRowLocation object.- Specified by:
recycle
in interfaceDataValueDescriptor
- Overrides:
recycle
in classDataType
- Returns:
- this object reset to its initial state
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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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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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compare
public boolean compare(int op, DataValueDescriptor other, boolean orderedNulls, boolean unknownRV)
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!)
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compare
public int compare(DataValueDescriptor other)
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.
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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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getRecordHandle
public RecordHandle getRecordHandle(ContainerHandle ch) throws StandardException
- Throws:
StandardException
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setFrom
void setFrom(RecordHandle rh)
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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.lang.ClassNotFoundException
- A class needed to read the stored form of this object could not be found.java.io.IOException
- See Also:
Externalizable.readExternal(java.io.ObjectInput)
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readExternalFromArray
public void readExternalFromArray(ArrayInputStream in) throws java.io.IOException, java.lang.ClassNotFoundException
Description copied from class:DataType
Read the DataValueDescriptor from the stream. The default implementation callsreadExternal()
, which accesses theArrayInputStream
as a generic stream. If sub-classes can implement it more efficiently by accessing the array, they should override this method.- Specified by:
readExternalFromArray
in interfaceDataValueDescriptor
- Overrides:
readExternalFromArray
in classDataType
- 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.- See Also:
DataValueDescriptor.readExternalFromArray(org.apache.derby.iapi.services.io.ArrayInputStream)
,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
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setFrom
protected void setFrom(DataValueDescriptor theValue)
Description copied from class:DataType
Set the value of this DataValueDescriptor based on the value of the specified DataValueDescriptor.
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equals
public boolean equals(java.lang.Object ref)
Implement value equality.
MT - Thread safe
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hashCode
public int hashCode()
Return a hashcode based on value.
MT - thread safe- Overrides:
hashCode
in classjava.lang.Object
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toString
public java.lang.String toString()
- Overrides:
toString
in classjava.lang.Object
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