Package com.tangosol.util.extractor

Class KeyExtractor<T,​E>

    • Field Detail

      • m_extractor

        protected ValueExtractor<? super T,​? extends E> m_extractor
        The underlying ValueExtractor.

    • Constructor Detail

      • KeyExtractor

        public KeyExtractor()
        Default constructor (necessary for the ExternalizableLite and PortableObject interfaces).

      • KeyExtractor

        public KeyExtractor​(ValueExtractor<? super T,​? extends E> extractor)
        Construct a KeyExtractor based on a specified ValueExtractor.
        Parameters:
        extractor - the underlying ValueExtractor

      • KeyExtractor

        public KeyExtractor​(String sMethod)
        Construct a KeyExtractor for a specified method name.
        Parameters:
        sMethod - a method name to construct an underlying ReflectionExtractor for; this parameter can also be a dot-delimited sequence of method names which would result in a KeyExtractor based on the ChainedExtractor that is based on an array of corresponding ReflectionExtractor objects

    • Method Detail

      • extract

        public E extract​(T 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<T,​E>
        Overrides:
        extract in class AbstractExtractor<T,​E>
        Parameters:
        oTarget - the object to extract the value from
        Returns:
        the extracted value; null is an acceptable value

      • getCanonicalName

        public String getCanonicalName()
        Description copied from interface: ValueExtractor
        Return the canonical name for this extractor.

        A canonical name uniquely identifies what is to be extracted, but not how it is to be extracted. Thus two different extractor implementations with the same non-null canonical name are considered to be equal, and should reflect this in their implementations of hashCode and equals.

        Canonical names for properties are designated by their property name in camel case, for instance a Java Bean with method getFooBar would have a property named fooBar, and would have fooBar as its canonical name.

        Canonical names for zero-arg method invocations are the method name followed by ().

        Dots in a canonical name delimit one or more property/method accesses represented by a chaining ValueExtractor such as ChainedExtractor or PofExtractor(Class, PofNavigator, String).

        There is currently no canonical name format for methods which take parameters and as such they must return a canonical name of null.

        Specified by:
        getCanonicalName in interface CanonicallyNamed
        Specified by:
        getCanonicalName in interface ValueExtractor<T,​E>
        Overrides:
        getCanonicalName in class AbstractExtractor<T,​E>
        Returns:
        the extractor's canonical name, or null

      • getExtractor

        public ValueExtractor<? super T,​? extends E> getExtractor()
        Obtain the underlying ValueExtractor.
        Returns:
        the ValueExtractor

      • of

        public static <T,​E> ValueExtractor<T,​E> of​(ValueExtractor<T,​E> extractor)
        Factory method for key extractor.
        Type Parameters:
        T - the type of the value to extract from
        E - the type of value that will be extracted
        Parameters:
        extractor - an extractor to convert to key extractor
        Returns:
        key extractor based on the specified extractor

      • toString

        public String toString()
        Return a human-readable description for this KeyExtractor.
        Overrides:
        toString in class Object
        Returns:
        a String description of the KeyExtractor

      • 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