Serializing java long type to php integer

[middlebrain]

Hi.

thanks for providing this serializer. Very helpful and easy to use.

With the current implementation however, there is no builtin adapter to serialize a java long to a php Integer. Casting long to int is not a good idea and writing a custom adapter seems not possible without extending the Writer class.

Another small issue: The documentation says, that registerBuiltinAdapters() registers all built-in adapters. That's not true. For example, the DoubleAdapter and the MapAdapter are missing.

[marcospassos]

Hi @middlebrain, thanks for reporting these issues.

With the current implementation however, there is no builtin adapter to serialize a java long to a php Integer. Casting long to int is not a good idea and writing a custom adapter seems not possible without extending the Writer class.

As you pointed out, longs cannot be cast to integers indiscriminately as it may overflow the limits of the integer type. The writer supports writing any data type supported on the PHP side, so I can't see how to handle it at this level. That being said, the most straightforward approach for handling this case is serializing longs to strings, the same approach largely adopted when serializing big numbers to JSON in most programming languages. Alternatively, you can write a custom adapter that converts longs to GMP numbers. In fact, the latter approach is pretty interesting, and I would consider accepting a PR if you want to implement it.

Notice that PHP will convert any value beyond the bounds of the integer type to a float, with precision loss. It means that you can just serialize longs as integers if the precision loss is not an issue for your requirements.

Another small issue: The documentation says, that registerBuiltinAdapters() registers all built-in adapters. That's not true. For example, the DoubleAdapter and the MapAdapter are missing.

You're right. I'll review it and release a new version fixing it.

Thank you for reporting it and let me know if you have any other issue.

[middlebrain]

I believe, that the Java type long can be easily converted to the PHP type integer, at least for 64bit target platforms. Unserializing on 32bit platforms is a problem of course.

So I was thinking of something like this:

Writer.java:

...
     /**
     * Writes an long value to the buffer.
     *
     * @param value The value.
     */
    public void writeLong(Long value)
    {
        setState(state.value());

        buffer.append("i:");
        buffer.append(value);
        buffer.append(';');
    }
...

adapter/LongAdapter.java:

package com.marcospassos.phpserializer.adapter;

import com.marcospassos.phpserializer.Context;
import com.marcospassos.phpserializer.TypeAdapter;
import com.marcospassos.phpserializer.Writer;

/**
 * Adapter for long values.
 */
public class LongAdapter implements TypeAdapter<Long>
{
    @Override
    public void write(Long value, Writer writer, Context context)
    {
        writer.writeLong(value);
    }
}

At least for my use case, that would be enough. Not perfect, but better then casting long to int on the java side.

[marcospassos]

Got your point now.

Could you please open a PR and add some tests to cover the feature?

[marcospassos]

As PHP makes no distinction between longs and integers, how about using method overloading instead of a new method?

  /**
     * Writes an long value to the buffer.
     *
     * @param value The value.
     */
    public void writInteger(Long value)
    {
        setState(state.value());

        buffer.append("i:");
        buffer.append(value);
        buffer.append(';');
    }

[middlebrain]

Even better. With my modest Java knowledge I didn't come up with that.

[marcospassos]

I just released the version 0.6.0 that covers this issue. Could you please check if it covers your use case?

You can check the full release description here:
https://github.com/marcospassos/java-php-serializer/releases/tag/0.6.0

[middlebrain]

Not yet. The DoubleAdapter is not correct registered in SerializerBuilder.java line 198:

registerAdapter(Double.class, new IntegerAdapter());

[marcospassos]

The bug is fixed. In addition, I've added several tests to avoid this kind of mistake.

Can you please confirm it fixes the issues?

[middlebrain]

It works out of the box now.

Thank you for your quick solution.

[marcospassos]

Closing as the issue has been fixed.