Stream Helper Methods in Java

The stream classes provide all of the low-level methods necessary for encoding and decoding Ice types. However, it would be tedious and error-prone to manually encode complex Ice types such as classes, structs, and dictionaries using these low-level functions. For this reason, the Slice compiler generates helper methods for streaming complex Ice types.

We will use the following Slice definitions to demonstrate the language mapping:

Slice

module M
{
    sequence<...> Seq;
    dictionary<...> Dict;
    struct S
    {
        ...
    }
    enum E { ... }
}

The Slice compiler generates the corresponding helper classes and methods shown below:

Java

package M;

public class SeqHelper
{
    public static T[] read(com.zeroc.Ice.InputStream in);
    public static void write(com.zeroc.Ice.OutputStream out, T[] v);

    public static java.util.Optional<T[]> read(com.zeroc.Ice.InputStream in, int tag);
    public static void write(com.zeroc.Ice.OutputStream out, int tag, java.util.Optional<T[]> v);
    public static void write(com.zeroc.Ice.OutputStream out, int tag, T[] v);
    ...
}

public class DictHelper
{
    public static java.util.Map<..., ...> read(com.zeroc.Ice.InputStream in);
    public static void write(com.zeroc.Ice.OutputStream out, java.util.Map<..., ...> v);

    public static java.util.Optional<java.util.Map<..., ...>> read(com.zeroc.Ice.InputStream in, int tag);
    public static void write(com.zeroc.Ice.OutputStream out, int tag, java.util.Optional<java.util.Map<..., ...>> v);
    public static void write(com.zeroc.Ice.OutputStream out, int tag, java.util.Map<..., ...> v);
    ...
}

public class S ...
{
    public static S ice_read(com.zeroc.Ice.InputStream in);
    public static void ice_write(com.zeroc.Ice.OutputStream out, S v);

    public static java.util.Optional<S> ice_read(com.zeroc.Ice.InputStream in, int tag);
    public static void ice_write(com.zeroc.Ice.OutputStream out, int tag, java.util.Optional<S> v);
    public static void ice_write(com.zeroc.Ice.OutputStream out, int tag, S v);
 
    // Instance methods
    public void ice_readMembers(com.zeroc.Ice.InputStream in);
    public void ice_writeMembers(com.zeroc.Ice.OutputStream out);
    ...
}

public enum E ...
{
    public static E ice_read(com.zeroc.Ice.InputStream in);
    public static void ice_write(com.zeroc.Ice.OutputStream out, E v);
 
    public static java.util.Optional<E> ice_read(com.zeroc.Ice.InputStream in, int tag);
    public static void ice_write(com.zeroc.Ice.OutputStream out, int tag, java.util.Optional<E> v);
    public static void ice_write(com.zeroc.Ice.OutputStream out, int tag, E v);

    // Instance method
    public void ice_write(com.zeroc.Ice.OutputStream out);
    ...
}

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