Package com.opencloud.rhino.util

Class EncodableMap<K,​V>

  • Type Parameters:
    K - map key type.
    V - map value type.
    All Implemented Interfaces:
    Encodable, Map<K,​V>
    public abstract class EncodableMap<K,​V>
extends Object
implements Map<K,​V>, Encodable

    Generic implementation of a map structure that can be stored in SLEE CMP fields with sensible serialisation semantics. This class essentially provides a layer on top of some other map implementation, delegating method calls on the Map interface through to the underlying map implementation, while handling the serialisation and deserialisation of the map’s state via the contract provided by the Encodable interface.

    In order to use this map, a subclass must be implemented that:

    • Provides at least a public constructor satisfying the contract of the Encodable interface.

    • Implements the abstract write* and read* methods defined in this class to serialise and deserialise individual map keys and values.

    This implementation provides the ability to specify what type of map structure to use as a backing store from a set of predefined types. A subclass may use an alternative map implementation by:

    Since:
    Rhino 2.4.0

    • Constructor Detail

      • EncodableMap

        public EncodableMap​(EncodableMap.BackingStore backingStore)

        Create an EncodableMap using the specified backing store.

        Parameters:
        backingStore - the backing store to use.

      • EncodableMap

        protected EncodableMap​(EncodableMap.BackingStore backingStore,
                       Map<K,​V> map)

        Create an EncodableSet using the specified backing store and map. This constructor may be used to create an EncodableMap that wraps a pre-existing map.

        Parameters:
        backingStore - the backing store to use.
        map - the initial map state.

      • EncodableMap

        protected EncodableMap​(DataInput in,
                       ClassLoader cl,
                       DecoderUtils utils)
                throws IOException

        Creates an EncodableMap with state restored from the specified input stream.

        Parameters:
        in - the input stream to read map state from.
        cl - classloader that can be used to resolve class dependencies.
        utils - additional utility decoding functions.
        Throws:
        IOException - if an I/O error occurs.

    • Method Detail

      • fromStream

        protected void fromStream​(DataInput in,
                          ClassLoader cl,
                          DecoderUtils utils)
                   throws IOException

        Populate map entries with state restored from the specified input stream. This method typically would only be used after the map has been cleared, and can be used to recycle the underlying map object.

        Warning: This method can only be used to deserialise a map serialised using the toStream(DataOutput, EncoderUtils) method. It will not work with a map serialised using the encode(DataOutput, EncoderUtils) method.

        Parameters:
        in - the input stream to read map state from.
        cl - classloader that can be used to resolve class dependencies.
        utils - additional utility decoding functions.
        Throws:
        IOException - if an I/O error occurs.

      • encode

        public void encode​(DataOutput out,
                   EncoderUtils utils)
            throws IOException
        Description copied from interface: Encodable

        Encode the state of this object to the given data output stream.

        Specified by:
        encode in interface Encodable
        Parameters:
        out - the data output stream to encode the value to.
        utils - additional utility encoding functions that may be useful to the encoder.
        Throws:
        IOException - if an I/O error occurs.

      • size

        public int size()
        Specified by:
        size in interface Map<K,​V>

      • isEmpty

        public boolean isEmpty()
        Specified by:
        isEmpty in interface Map<K,​V>

      • containsKey

        public boolean containsKey​(Object key)
        Specified by:
        containsKey in interface Map<K,​V>

      • get

        public V get​(Object key)
        Specified by:
        get in interface Map<K,​V>

      • put

        public V put​(K key,
             V value)
        Specified by:
        put in interface Map<K,​V>

      • remove

        public V remove​(Object key)
        Specified by:
        remove in interface Map<K,​V>

      • putAll

        public void putAll​(Map<? extends K,​? extends V> m)
        Specified by:
        putAll in interface Map<K,​V>

      • clear

        public void clear()
        Specified by:
        clear in interface Map<K,​V>

      • keySet

        public Set<K> keySet()
        Specified by:
        keySet in interface Map<K,​V>

      • newMapInstance

        protected Map<K,​V> newMapInstance​(EncodableMap.BackingStore backingStore)

        Create a new map instance for the backing store. The default behaviour of this method simply returns the value of backingStore.createMap().

        Parameters:
        backingStore - the backing store originally passed in to the class constructor when the EncodableMap was first created.
        Returns:
        a map.

      • writeKey

        protected abstract void writeKey​(K key,
                                 DataOutput out,
                                 EncoderUtils utils)
                          throws IOException

        Serialise the specified map key to the output stream.

        Parameters:
        key - the map key, may be null if the underlying map supports null keys and manageNullKeys() return false.
        out - the output stream to write the key state to.
        utils - additional utility encoding functions that may be useful when serialising the key.
        Throws:
        IOException - if an I/O error occurs.

      • writeValue

        protected abstract void writeValue​(V value,
                                   DataOutput out,
                                   EncoderUtils utils)
                            throws IOException

        Serialise the specified map value to the output stream.

        Parameters:
        value - the map value, may be null if the underlying map supports null values and manageNullValues() return false.
        out - the output stream to write the value state to.
        utils - additional utility encoding functions that may be useful when serialising the value.
        Throws:
        IOException - if an I/O error occurs.

      • readKey

        protected abstract K readKey​(DataInput in,
                             ClassLoader cl,
                             DecoderUtils utils)
                      throws IOException

        Deserialise a map key from the input stream.

        Parameters:
        in - the input stream to read the key state from.
        cl - classloader that can be used to resolve class dependencies.
        utils - additional utility decoding functions that may be useful when deserialising the key.
        Returns:
        a map key.
        Throws:
        IOException - if an I/O error occurs.

      • readValue

        protected abstract V readValue​(DataInput in,
                               ClassLoader cl,
                               DecoderUtils utils)
                        throws IOException

        Deserialise a map value from the input stream.

        Parameters:
        in - the input stream to read the value state from.
        cl - classloader that can be used to resolve class dependencies.
        utils - additional utility decoding functions that may be useful when deserialising the value.
        Returns:
        a map value.
        Throws:
        IOException - if an I/O error occurs.