Package db
Class Field
- java.lang.Object
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- db.Field
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- All Implemented Interfaces:
java.lang.Comparable<Field>
- Direct Known Subclasses:
BinaryField
,BooleanField
,ByteField
,IntField
,LongField
,ShortField
,StringField
public abstract class Field extends java.lang.Object implements java.lang.Comparable<Field>
Field
is an abstract data wrapper for use with Records. Note that when comparing two Field instances both must be of the same class.Fields may take on a null state. In the case of
FixedField
andPrimitiveField
this state is distinct from value and only applies when used for a sparse column within aSparseRecord
. In this sparse column situation theSparseRecord.setField(int, Field)
method may be passed a null Field argument. Sparse columns with a null value/state will not be indexed within aTable
.Stored Schema Field Type Encoding:
8-bit Legacy Field Type Encoding (I....FFF)
Supported encodings: 0x00..0x06 and 0x80..0x86, where:FFF - indexed field type (0..6) I - index field indicator (only long primary keys were supported)
8-bit Field Type Encoding (PPPPFFFF)
(Reserved for future field extensions: 0x88 and 0xf0..0xff)0xff - see
where:Schema.FIELD_EXTENSION_INDICATOR
FFFF - normal/indexed field type PPPP - indexed table primary key type (1000b: LegacyIndexField)
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Nested Class Summary
Nested Classes Modifier and Type Class Description static class
Field.UnsupportedFieldException
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Field Summary
Fields Modifier and Type Field Description static Field[]
EMPTY_ARRAY
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Method Summary
All Methods Static Methods Instance Methods Abstract Methods Concrete Methods Modifier and Type Method Description static boolean
canIndex(Field field)
Determine if a specified field instance may be indexedabstract int
compareTo(Field otherField)
Compares this Field with another Field for order.abstract Field
copyField()
Create new instance of this field with the same value.abstract boolean
equals(java.lang.Object obj)
Determine if the specified Object is another Field which has the same type and value as this Field.abstract byte[]
getBinaryData()
Get data as a byte array.boolean
getBooleanValue()
Get field as a boolean value.byte
getByteValue()
Get field as a byte value.int
getIntValue()
Get field as an integer value.long
getLongValue()
Get field as a long value.short
getShortValue()
Get field as a short value.java.lang.String
getString()
Get field as a String value.abstract java.lang.String
getValueAsString()
Get field value as a formatted stringabstract int
hashCode()
abstract boolean
isNull()
Determine if the field has been set to a null-state or value.boolean
isSameType(Field field)
Determine if specified field is same type as this fieldboolean
isVariableLength()
abstract Field
newField()
Create new instance of this field type.abstract void
setBinaryData(byte[] bytes)
Set data from binary byte array.void
setBooleanValue(boolean value)
Set field's boolean value.void
setByteValue(byte value)
Set field's byte value.void
setIntValue(int value)
Set field's integer value.void
setLongValue(long value)
Set field's long value.void
setShortValue(short value)
Set field's short value.void
setString(java.lang.String str)
Set field's String value.
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Field Detail
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EMPTY_ARRAY
public static final Field[] EMPTY_ARRAY
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Method Detail
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getLongValue
public long getLongValue()
Get field as a long value. All fixed-length field objects must implement this method- Returns:
- long value
- Throws:
IllegalFieldAccessException
- thrown if method is not supported by specific Field instance.
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setLongValue
public void setLongValue(long value)
Set field's long value. All fixed-length field objects must implement this method- Parameters:
value
- long value- Throws:
IllegalFieldAccessException
- thrown if method is not supported by specific Field instance.
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getIntValue
public int getIntValue()
Get field as an integer value.- Returns:
- integer value
- Throws:
IllegalFieldAccessException
- thrown if method is not supported by specific Field instance.
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setIntValue
public void setIntValue(int value)
Set field's integer value.- Parameters:
value
- integer value- Throws:
IllegalFieldAccessException
- thrown if method is not supported by specific Field instance.
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getShortValue
public short getShortValue()
Get field as a short value.- Returns:
- short value
- Throws:
IllegalFieldAccessException
- thrown if method is not supported by specific Field instance.
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setShortValue
public void setShortValue(short value)
Set field's short value.- Parameters:
value
- short value- Throws:
IllegalFieldAccessException
- thrown if method is not supported by specific Field instance.
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getByteValue
public byte getByteValue()
Get field as a byte value.- Returns:
- byte value
- Throws:
IllegalFieldAccessException
- thrown if method is not supported by specific Field instance.
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setByteValue
public void setByteValue(byte value)
Set field's byte value.- Parameters:
value
- byte value- Throws:
IllegalFieldAccessException
- thrown if method is not supported by specific Field instance.
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getBooleanValue
public boolean getBooleanValue()
Get field as a boolean value.- Returns:
- boolean value
- Throws:
IllegalFieldAccessException
- thrown if method is not supported by specific Field instance.
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setBooleanValue
public void setBooleanValue(boolean value)
Set field's boolean value.- Parameters:
value
- boolean value- Throws:
IllegalFieldAccessException
- thrown if method is not supported by specific Field instance.
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getBinaryData
public abstract byte[] getBinaryData()
Get data as a byte array.- Returns:
- byte[]
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setBinaryData
public abstract void setBinaryData(byte[] bytes)
Set data from binary byte array. All variable-length fields must implement this method.- Parameters:
bytes
- field data- Throws:
IllegalFieldAccessException
- if error occurs while reading bytes into field which will generally be caused by the incorrect number of bytes provided to a fixed-length field.
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getString
public java.lang.String getString()
Get field as a String value.- Returns:
- String value
- Throws:
IllegalFieldAccessException
- thrown if method is not supported by specific Field instance.
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setString
public void setString(java.lang.String str)
Set field's String value.- Parameters:
str
- String value- Throws:
IllegalFieldAccessException
- thrown if method is not supported by specific Field instance.
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isVariableLength
public boolean isVariableLength()
- Returns:
- true if a Field instance is variable length, else false.
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isSameType
public boolean isSameType(Field field)
Determine if specified field is same type as this field- Parameters:
field
- a Field instance- Returns:
- true if field is same type as this field
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copyField
public abstract Field copyField()
Create new instance of this field with the same value.- Returns:
- new field instance with same value
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newField
public abstract Field newField()
Create new instance of this field type.- Returns:
- new field instance with undefined initial value
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equals
public abstract boolean equals(java.lang.Object obj)
Determine if the specified Object is another Field which has the same type and value as this Field. When comparing aPrimitiveField
, with a null state, a value of zero (0) is used.- Overrides:
equals
in classjava.lang.Object
- Parameters:
obj
- another object- Returns:
- true if this field equals obj
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hashCode
public abstract int hashCode()
- Overrides:
hashCode
in classjava.lang.Object
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getValueAsString
public abstract java.lang.String getValueAsString()
Get field value as a formatted string- Returns:
- field value string
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isNull
public abstract boolean isNull()
Determine if the field has been set to a null-state or value.- Returns:
- true if field has been set to a null state or value, else false
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compareTo
public abstract int compareTo(Field otherField)
Compares this Field with another Field for order. Returns a negative integer, zero, or a positive integer as this object is less than, equal to, or greater than the specified Field.
NOTE: Field objects do not fully comply with the Comparable interface. Only the same Field implementations may be compared. In addition, the null state is not considered when comparingPrimitiveField
s which have a zero (0) value.- Specified by:
compareTo
in interfacejava.lang.Comparable<Field>
- Parameters:
otherField
- another Field which is the same type as this Field- Returns:
- field comparison result (see
Comparable.compareTo(Object)
). - Throws:
java.lang.ClassCastException
- if an attempt to compare dissimilar Fields (e.g., an IntField may not be compared with a ShortField).
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canIndex
public static boolean canIndex(Field field)
Determine if a specified field instance may be indexed- Parameters:
field
- field to be checked- Returns:
- true if field can be indexed
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