- java.lang.Object
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- org.snmp4j.smi.AbstractVariable
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- All Implemented Interfaces:
java.io.Serializable,java.lang.Cloneable,java.lang.Comparable<Variable>,BERSerializable,Variable
- Direct Known Subclasses:
Counter64,Integer32,Null,OctetString,OID,SMIAddress,UnsignedInteger32,VariantVariable
public abstract class AbstractVariable extends java.lang.Object implements Variable, java.io.Serializable
TheVariableabstract class is the base class for all SNMP variables.All derived classes need to be registered with their SMI BER type in the
smisyntaxes.propertiesso that thecreateFromBER(BERInputStream inputStream)method is able to decode a variable from a BER encoded stream.To register additional syntaxes, set the system property
SMISYNTAXES_PROPERTIESbefore decoding a Variable for the first time. The path of the property file must be accessible from the classpath and it has to be specified relative to theVariableclass.- Since:
- 1.8
- Version:
- 1.8
- Author:
- Frank Fock, Jochen Katz
- See Also:
- Serialized Form
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Field Summary
Fields Modifier and Type Field Description static java.lang.StringSMISYNTAXES_PROPERTIES
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Constructor Summary
Constructors Constructor Description AbstractVariable()The abstractVariableclass serves as the base class for all specific SNMP syntax types.
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Method Summary
All Methods Static Methods Instance Methods Abstract Methods Concrete Methods Modifier and Type Method Description abstract java.lang.Objectclone()Clones this variable.abstract intcompareTo(Variable o)static VariablecreateFromBER(BERInputStream inputStream)Creates aVariablefrom a BER encodedBERInputStream.static VariablecreateFromSyntax(int smiSyntax)Creates aVariablefrom the supplied SMI syntax identifier.abstract voiddecodeBER(BERInputStream inputStream)Decodes aVariablefrom anBERInputStream.abstract voidencodeBER(java.io.OutputStream outputStream)Encodes aVariableto anOutputStream.static booleanequal(AbstractVariable a, AbstractVariable b)Tests if two variables have the same value.abstract booleanequals(java.lang.Object o)abstract voidfromSubIndex(OID subIndex, boolean impliedLength)Sets the value of thisVariablefrom the supplied (sub-)index.abstract intgetBERLength()Returns the length of thisVariablein bytes when encoded according to the Basic Encoding Rules (BER).intgetBERPayloadLength()Returns the length of the payload of thisBERSerializableobject in bytes when encoded according to the Basic Encoding Rules (BER).abstract intgetSyntax()Gets the ASN.1 syntax identifier value of this SNMP variable.static intgetSyntaxFromString(java.lang.String syntaxString)Returns the BER syntax ID for the supplied syntax string (as returned bygetSyntaxString(int)).java.lang.StringgetSyntaxString()Gets a textual description of this Variable.static java.lang.StringgetSyntaxString(int syntax)Gets a textual description of the supplied syntax type.abstract inthashCode()booleanisDynamic()Indicates whether this variable is dynamic, which means that it might change its value while it is being (BER) serialized.booleanisException()Checks whether this variable represents an exception like noSuchObject, noSuchInstance, and endOfMibView.abstract inttoInt()Returns an integer representation of this variable if such a representation exists.abstract longtoLong()Returns a long representation of this variable if such a representation exists.abstract java.lang.StringtoString()Gets a string representation of the variable.abstract OIDtoSubIndex(boolean impliedLength)Converts the value of thisVariableto a (sub-)index value.
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Field Detail
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SMISYNTAXES_PROPERTIES
public static final java.lang.String SMISYNTAXES_PROPERTIES
- See Also:
- Constant Field Values
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Method Detail
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equals
public abstract boolean equals(java.lang.Object o)
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compareTo
public abstract int compareTo(Variable o)
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hashCode
public abstract int hashCode()
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getBERLength
public abstract int getBERLength()
Returns the length of thisVariablein bytes when encoded according to the Basic Encoding Rules (BER).- Specified by:
getBERLengthin interfaceBERSerializable- Returns:
- the BER encoded length of this variable.
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getBERPayloadLength
public int getBERPayloadLength()
Description copied from interface:BERSerializableReturns the length of the payload of thisBERSerializableobject in bytes when encoded according to the Basic Encoding Rules (BER).- Specified by:
getBERPayloadLengthin interfaceBERSerializable- Returns:
- the BER encoded length of this variable.
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decodeBER
public abstract void decodeBER(BERInputStream inputStream) throws java.io.IOException
Decodes aVariablefrom anBERInputStream.- Specified by:
decodeBERin interfaceBERSerializable- Parameters:
inputStream- anBERInputStreamcontaining a BER encoded byte stream.- Throws:
java.io.IOException- if the stream could not be decoded by using BER rules.
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encodeBER
public abstract void encodeBER(java.io.OutputStream outputStream) throws java.io.IOExceptionEncodes aVariableto anOutputStream.- Specified by:
encodeBERin interfaceBERSerializable- Parameters:
outputStream- anOutputStream.- Throws:
java.io.IOException- if an error occurs while writing to the stream.
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createFromBER
public static Variable createFromBER(BERInputStream inputStream) throws java.io.IOException
Creates aVariablefrom a BER encodedBERInputStream. Subclasses ofVariableare registered using the properties filesmisyntaxes.propertiesin this package. The properties are read when this method is called first.- Parameters:
inputStream- anBERInputStreamcontaining a BER encoded byte stream.- Returns:
- an instance of a subclass of
Variable. - Throws:
java.io.IOException- if theinputStreamis not properly BER encoded.
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createFromSyntax
public static Variable createFromSyntax(int smiSyntax)
Creates aVariablefrom the supplied SMI syntax identifier. Subclasses ofVariableare registered using the properties filesmisyntaxes.propertiesin this package. The properties are read when this method is called for the first time.- Parameters:
smiSyntax- an SMI syntax identifier of the registered types, which is typically defined bySMIConstants.- Returns:
- a
Variablevariable instance of the supplied SMI syntax.
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getSyntax
public abstract int getSyntax()
Gets the ASN.1 syntax identifier value of this SNMP variable.
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isException
public boolean isException()
Checks whether this variable represents an exception like noSuchObject, noSuchInstance, and endOfMibView.- Specified by:
isExceptionin interfaceVariable- Returns:
trueif the syntax of this variable is an instance ofNulland its syntax equals one of the following:
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toString
public abstract java.lang.String toString()
Gets a string representation of the variable.
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toInt
public abstract int toInt()
Returns an integer representation of this variable if such a representation exists.- Specified by:
toIntin interfaceVariable- Returns:
- an integer value (if the native representation of this variable would be a long, then the long value will be casted to int).
- Throws:
java.lang.UnsupportedOperationException- if an integer representation does not exists for this Variable.- Since:
- 1.7
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toLong
public abstract long toLong()
Returns a long representation of this variable if such a representation exists.
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clone
public abstract java.lang.Object clone()
Description copied from interface:VariableClones this variable. Cloning can be used by the SNMP4J API to better support concurrency by creating a clone for internal processing. The content of this object is independent to the content of the clone. Thus, changes to the clone will have no effect to this object.
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getSyntaxString
public static java.lang.String getSyntaxString(int syntax)
Gets a textual description of the supplied syntax type.- Parameters:
syntax- the BER code of the syntax.- Returns:
- a textual description like 'Integer32' for
syntaxas used in the Structure of Management Information (SMI) modules. '?' is returned if the supplied syntax is unknown.
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getSyntaxString
public final java.lang.String getSyntaxString()
Gets a textual description of this Variable.- Specified by:
getSyntaxStringin interfaceVariable- Returns:
- a textual description like 'Integer32' as used in the Structure of Management Information (SMI) modules. '?' is returned if the syntax is unknown.
- Since:
- 1.7
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getSyntaxFromString
public static int getSyntaxFromString(java.lang.String syntaxString)
Returns the BER syntax ID for the supplied syntax string (as returned bygetSyntaxString(int)).- Parameters:
syntaxString- the textual representation of the syntax.- Returns:
- the corresponding BER ID.
- Since:
- 1.6
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toSubIndex
public abstract OID toSubIndex(boolean impliedLength)
Converts the value of thisVariableto a (sub-)index value.- Specified by:
toSubIndexin interfaceVariable- Parameters:
impliedLength- specifies if the sub-index has an implied length. This parameter applies to variable length variables only (e.g.OctetStringandOID). For other variables it has no effect.- Returns:
- an OID that represents this value as an (sub-)index.
- Throws:
java.lang.UnsupportedOperationException- if this variable cannot be used in an index.- Since:
- 1.7
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fromSubIndex
public abstract void fromSubIndex(OID subIndex, boolean impliedLength)
Sets the value of thisVariablefrom the supplied (sub-)index.- Specified by:
fromSubIndexin interfaceVariable- Parameters:
subIndex- the sub-index OID.impliedLength- specifies if the sub-index has an implied length. This parameter applies to variable length variables only (e.g.OctetStringandOID). For other variables it has no effect.- Throws:
java.lang.UnsupportedOperationException- if this variable cannot be used in an index.- Since:
- 1.7
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isDynamic
public boolean isDynamic()
Indicates whether this variable is dynamic, which means that it might change its value while it is being (BER) serialized. If a variable is dynamic, it will be cloned on-the-fly when it is added to aPDUwithPDU.add(VariableBinding). By cloning the value, it is ensured that there are no inconsistent changes between determining the length withgetBERLength()for encoding enclosing SEQUENCES and the actual encoding of the Variable itself withencodeBER(java.io.OutputStream).
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equal
public static boolean equal(AbstractVariable a, AbstractVariable b)
Tests if two variables have the same value.- Parameters:
a- a variable.b- another variable.- Returns:
trueifa == null) ? (b == null) : a.equals(b).- Since:
- 2.0
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