org.arl.fjage.remote.GenericValueAdapterFactory.java Source code

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Here is the source code for org.arl.fjage.remote.GenericValueAdapterFactory.java

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/******************************************************************************
    
Copyright (c) 2015, Mandar Chitre
    
This file is part of fjage which is released under Simplified BSD License.
See file LICENSE.txt or go to http://www.opensource.org/licenses/BSD-3-Clause
for full license details.
    
******************************************************************************/

package org.arl.fjage.remote;

import java.io.IOException;
import java.nio.*;
import java.util.Base64;
import com.google.gson.*;
import com.google.gson.stream.*;
import com.google.gson.reflect.TypeToken;
import org.arl.fjage.GenericValue;

/**
 * Array adapter factory for custom JSON representation.
 *
 * Numeric arrays are compressed into a base 64 notation for quick transmission
 * over a network.
 */
@SuppressWarnings({ "unchecked", "rawtypes" })
class GenericValueAdapterFactory implements TypeAdapterFactory {

    public <T> TypeAdapter<T> create(final Gson gson, TypeToken<T> type) {
        final Class<T> rawType = (Class<T>) type.getRawType();
        if (!rawType.equals(GenericValue.class))
            return null;
        final GenericValueAdapterFactory parent = this;
        return new TypeAdapter<T>() {

            @Override
            public void write(JsonWriter out, T value) throws IOException {
                if (value == null) {
                    out.nullValue();
                    return;
                }
                Class type = ((GenericValue) value).getType();
                if (type == null) {
                    out.nullValue();
                    return;
                }
                if (Number.class.isAssignableFrom(type))
                    out.value((Number) ((GenericValue) value).getValue());
                else if (type.equals(String.class))
                    out.value((String) ((GenericValue) value).getValue());
                else if (type.equals(Boolean.class))
                    out.value((Boolean) ((GenericValue) value).getValue());
                else {
                    out.beginObject();
                    out.name("clazz").value(type.getName());
                    out.name("data");
                    TypeAdapter delegate = gson.getAdapter(TypeToken.get(type));
                    Object v = ((GenericValue) value).getValue();
                    delegate.write(out, v);
                    out.endObject();
                }
            }

            @Override
            public T read(JsonReader in) throws IOException {
                JsonToken tok = in.peek();
                if (tok == JsonToken.NULL) {
                    in.nextNull();
                    return null;
                }
                if (tok == JsonToken.NUMBER) {
                    String s = in.nextString();
                    try {
                        if (s.contains("."))
                            return (T) new GenericValue(Double.parseDouble(s));
                        else
                            return (T) new GenericValue(Long.parseLong(s));
                    } catch (NumberFormatException ex) {
                        return (T) new GenericValue(null);
                    }
                }
                if (tok == JsonToken.STRING)
                    return (T) new GenericValue(in.nextString());
                if (tok == JsonToken.BOOLEAN)
                    return (T) new GenericValue(in.nextBoolean());
                if (tok != JsonToken.BEGIN_OBJECT)
                    return null;
                TypeToken tt = null;
                GenericValue rv = null;
                in.beginObject();
                while (in.hasNext()) {
                    String name = in.nextName();
                    if (name.equals("clazz")) {
                        try {
                            Class<?> cls = Class.forName(in.nextString());
                            tt = TypeToken.get(cls);
                        } catch (Exception ex) {
                            // do nothing
                        }
                    } else if (name.equals("data") && tt != null) {
                        TypeAdapter delegate = gson.getAdapter(tt);
                        rv = new GenericValue(delegate.read(in));
                    } else
                        in.skipValue();
                }
                in.endObject();
                return (T) rv;
            }

        };
    }

}