MultiJSONCollectionSerializator.java

package org.jboss.capedwarf.common.serialization;

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import org.json.JSONTokener;

import java.io.IOException;
import java.io.InputStream;
import java.io.Writer;
import java.util.Collection;

/**
 * JSON collection based serializator.
 *
 * @author <a href="mailto:ales.justin@jboss.org">Ales Justin</a>
 */
public class MultiJSONCollectionSerializator extends AbstractJSONSerializator {
    private JSONAwareInstanceProvider instanceProvider;

    public MultiJSONCollectionSerializator(JSONAwareInstanceProvider instanceProvider) {
        if (instanceProvider == null)
            throw new IllegalArgumentException("Null instance provider");
        this.instanceProvider = instanceProvider;
    }

    public boolean isValid(Class<?> clazz) {
        return Collection.class.isAssignableFrom(clazz);
    }

    @SuppressWarnings({"unchecked"})
    public void serialize(Object instance, Writer writer) throws IOException {
        if (instance instanceof Collection == false)
            throw new IllegalArgumentException("Not a collection: " + instance);

        Collection<JSONAware> collection = (Collection<JSONAware>) instance;
        JSONArray jarray = new JSONArray();
        try {
            for (JSONAware elt : collection) {
                JSONObject jsonObject = createObject();
                elt.writeJSONObject(jsonObject);
                jarray.put(jsonObject);
            }
            writeArray(jarray, writer);
        } catch (JSONException e) {
            IOException ioe = new IOException();
            ioe.initCause(e);
            throw ioe;
        }
    }

    @SuppressWarnings({"unchecked"})
    public <T> T deserialize(InputStream stream, Class<T> clazz) throws IOException {
        if (isValid(clazz) == false)
            throw new IllegalArgumentException("Not a JSONAware class: " + clazz);

        try {
            JSONTokener tokener = createTokener(stream);
            JSONArray value = new JSONArray(tokener);
            T instance = clazz.newInstance();
            Collection<JSONAware> collection = (Collection<JSONAware>) instance;
            for (int i = 0; i < value.length(); i++) {
                JSONAware ja = instanceProvider.createInstance(i);
                ja.readJSONObject(value.getJSONObject(i));
                collection.add(ja);
            }
            return instance;
        } catch (IOException e) {
            throw e;
        } catch (Exception e) {
            IOException ioe = new IOException();
            ioe.initCause(e);
            throw ioe;
        } finally {
            stream.close();
        }
    }
}