com.tangosol.util.extractor
Class ReflectionExtractor

java.lang.Object
  com.tangosol.util.Base
      com.tangosol.util.extractor.AbstractExtractor
          com.tangosol.util.extractor.ReflectionExtractor

All Implemented Interfaces:

ExternalizableLite, PortableObject, QueryMapComparator, ValueExtractor, Serializable, Comparator

public class ReflectionExtractor
extends AbstractExtractor
implements ValueExtractor, ExternalizableLite, PortableObject

Reflection-based ValueExtractor implementation.

Author:

cp/gg 2002.11.01, ew 2007.02.01

See Also:

ChainedExtractor

Field Summary

protected Object[]	m_aoParam The parameter array.
protected String	m_sMethod The name of the method to invoke.

Constructor Summary

ReflectionExtractor()
Default constructor (necessary for the ExternalizableLite interface).

ReflectionExtractor(String sMethod)
Construct a ReflectionExtractor based on a method name.

ReflectionExtractor(String sMethod, Object[] aoParam)
Construct a ReflectionExtractor based on a method name and optional parameters.

Method Summary

boolean	equals(Object o) Compare the ReflectionExtractor with another object to determine equality.
Object	extract(Object oTarget) Extract the value from the passed object. The returned value may be null. For intrinsic types, the returned value is expected to be a standard wrapper type in the same manner that reflection works; for example, int would be returned as a java.lang.Integer.
String	getMethodName() Determine the name of the method that this extractor is configured to invoke.
Object[]	getParameters() Return the array of arguments used to invoke the method.
int	hashCode() Determine a hash value for the ReflectionExtractor object according to the general Object.hashCode() contract.
void	readExternal(DataInput in) Restore the contents of this object by loading the object's state from the passed DataInput object.
void	readExternal(PofReader in) Restore the contents of a user type instance by reading its state using the specified PofReader object.
String	toString() Provide a human-readable description of this ReflectionExtractor object.
void	writeExternal(DataOutput out) Save the contents of this object by storing the object's state into the passed DataOutput object.
void	writeExternal(PofWriter out) Save the contents of a POF user type instance by writing its state using the specified PofWriter object.

Methods inherited from class com.tangosol.util.extractor.AbstractExtractor

compare, compareEntries

Field Detail

m_sMethod

protected String m_sMethod

The name of the method to invoke.

m_aoParam

protected Object[] m_aoParam

The parameter array.

Constructor Detail

ReflectionExtractor

public ReflectionExtractor()

Default constructor (necessary for the ExternalizableLite interface).

ReflectionExtractor

public ReflectionExtractor(String sMethod)

Construct a ReflectionExtractor based on a method name.

Parameters:

sMethod - the name of the method to invoke via reflection

ReflectionExtractor

public ReflectionExtractor(String sMethod,
                           Object[] aoParam)

Construct a ReflectionExtractor based on a method name and optional parameters.

Parameters:

sMethod - the name of the method to invoke via reflection

aoParam - the array of arguments to be used in the method invocation; may be null

Since:

Coherence 3.3

Method Detail

extract

public Object extract(Object oTarget)

Extract the value from the passed object. The returned value may be null. For intrinsic types, the returned value is expected to be a standard wrapper type in the same manner that reflection works; for example, int would be returned as a java.lang.Integer.

Specified by:

extract in interface ValueExtractor

Specified by:

extract in class AbstractExtractor

Parameters:

oTarget - an Object to retrieve the value from

Returns:

the extracted value as an Object; null is an acceptable value

equals

public boolean equals(Object o)

Compare the ReflectionExtractor with another object to determine equality. Two ReflectionExtractor objects, re1 and re2 are considered equal iff re1.extract(o) equals re2.extract(o) for all values of o.

Specified by:

equals in interface ValueExtractor

Specified by:

equals in interface Comparator

Parameters:

o - the reference object with which to compare

Returns:

true iff this ReflectionExtractor and the passed object are equivalent ReflectionExtractors

hashCode

public int hashCode()

Determine a hash value for the ReflectionExtractor object according to the general Object.hashCode() contract.

Specified by:

hashCode in interface ValueExtractor

Returns:

an integer hash value for this ReflectionExtractor object

toString

public String toString()

Provide a human-readable description of this ReflectionExtractor object.

Specified by:

toString in interface ValueExtractor

Returns:

a human-readable description of this ReflectionExtractor object

getMethodName

public String getMethodName()

Determine the name of the method that this extractor is configured to invoke.

Returns:

the name of the method to invoke using reflection

getParameters

public Object[] getParameters()

Return the array of arguments used to invoke the method.

Returns:

the array of arguments used to invoke the method

readExternal

public void readExternal(DataInput in)
                  throws IOException

Restore the contents of this object by loading the object's state from the passed DataInput object.

Specified by:

readExternal in interface ExternalizableLite

Parameters:

in - the DataInput stream to read data from in order to restore the state of this object

Throws:

IOException - if an I/O exception occurs

NotActiveException - if the object is not in its initial state, and therefore cannot be deserialized into

writeExternal

public void writeExternal(DataOutput out)
                   throws IOException

Save the contents of this object by storing the object's state into the passed DataOutput object.

Specified by:

writeExternal in interface ExternalizableLite

Parameters:

out - the DataOutput stream to write the state of this object to

Throws:

IOException - if an I/O exception occurs

readExternal

public void readExternal(PofReader in)
                  throws IOException

Restore the contents of a user type instance by reading its state using the specified PofReader object.

Specified by:

readExternal in interface PortableObject

Parameters:

in - the PofReader from which to read the object's state

Throws:

IOException - if an I/O error occurs

writeExternal

public void writeExternal(PofWriter out)
                   throws IOException

Save the contents of a POF user type instance by writing its state using the specified PofWriter object.

Specified by:

writeExternal in interface PortableObject

Parameters:

out - the PofWriter to which to write the object's state

Throws:

IOException - if an I/O error occurs