mx.ipn.escom.supernaut.nile.logic.CommonBean.java Source code

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Here is the source code for mx.ipn.escom.supernaut.nile.logic.CommonBean.java

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/*
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 * template file, choose Tools | Templates and open the template in the editor.
 */
package mx.ipn.escom.supernaut.nile.logic;

import com.google.gson.Gson;
import com.google.gson.stream.JsonReader;
import com.google.gson.stream.JsonWriter;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.PipedInputStream;
import java.io.PipedOutputStream;
import java.lang.reflect.ParameterizedType;
import java.net.URI;
import java.nio.charset.StandardCharsets;
import java.util.List;
import javax.ejb.PrePassivate;
import org.apache.http.Header;
import org.apache.http.HttpEntity;
import org.apache.http.HttpHost;
import org.apache.http.HttpResponse;
import org.apache.http.StatusLine;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpDelete;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.client.methods.HttpPut;
import org.apache.http.entity.InputStreamEntity;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.message.BasicHeader;

/**
 *
 * @author supernaut
 */
public abstract class CommonBean<PK, Model> implements CommonBeanInterface<PK, Model> {

    protected static final HttpHost HOST = new HttpHost("localhost", 8081, "http");
    protected static final Header JSON_IN_HEAD = new BasicHeader("accept", "application/json; charset=utf-8");
    protected static final Header JSON_OUT_HEAD = new BasicHeader("content-type",
            "application/json; charset=utf-8");
    protected final Gson gson;
    protected final HttpClient client;
    protected final URI baseUri;
    protected final Class<Model> modelType;
    protected Model model;

    public CommonBean() {
        gson = new Gson();
        client = HttpClients.createDefault();
        modelType = (Class<Model>) ((ParameterizedType) getClass().getGenericSuperclass())
                .getActualTypeArguments()[0];
        baseUri = URI.create(HOST.toURI() + "/resources/" + modelType.getName().toLowerCase());
    }

    protected abstract String getPkAsParams();

    protected InputStream streamedMarshall() throws IOException {
        PipedInputStream in = new PipedInputStream();
        OutputStream out = new PipedOutputStream(in);
        JsonWriter writer = new JsonWriter(new OutputStreamWriter(out, StandardCharsets.UTF_8));
        gson.toJson(model, modelType, writer);
        return in;
    }

    protected void streamedUnmarshall(HttpEntity entity) throws IOException {
        model = gson.fromJson(new JsonReader(new InputStreamReader(entity.getContent(), StandardCharsets.UTF_8)),
                modelType);
    }

    @Override
    public void initByPK(PK pk) {
        HttpGet request = new HttpGet(baseUri + getPkAsParams());
        request.addHeader(JSON_IN_HEAD);
        HttpResponse response;
        try {
            response = client.execute(HOST, request);
            streamedUnmarshall(response.getEntity());
        } catch (IOException ex) {
            throw new RuntimeException(ex);
        }
        StatusLine statusLine = response.getStatusLine();
        if (statusLine.getStatusCode() < 200 || statusLine.getStatusCode() > 299)
            throw new RuntimeException(statusLine.getReasonPhrase());
    }

    @Override
    public void initNew(Model model) {
        HttpPost request = new HttpPost(baseUri);
        request.addHeader(JSON_OUT_HEAD);
        HttpResponse response;
        try {
            request.setEntity(new InputStreamEntity(streamedMarshall()));
            response = client.execute(HOST, request);
        } catch (IOException ex) {
            throw new RuntimeException(ex);
        }
        StatusLine statusLine = response.getStatusLine();
        if (statusLine.getStatusCode() < 200 || statusLine.getStatusCode() > 299)
            throw new RuntimeException(statusLine.getReasonPhrase());
        this.model = model;
    }

    @Override
    public List<Model> getAll() {
        List<Model> list;
        HttpGet request = new HttpGet(baseUri);
        request.addHeader(JSON_IN_HEAD);
        HttpResponse response;
        try {
            response = client.execute(HOST, request);
            list = (List<Model>) gson.fromJson(
                    new JsonReader(
                            new InputStreamReader(response.getEntity().getContent(), StandardCharsets.UTF_8)),
                    List.class);
        } catch (IOException ex) {
            throw new RuntimeException(ex);
        }
        StatusLine statusLine = response.getStatusLine();
        if (statusLine.getStatusCode() < 200 || statusLine.getStatusCode() > 299)
            throw new RuntimeException(statusLine.getReasonPhrase());
        return list;
    }

    @Override
    public Model getModel() {
        return model;
    }

    @Override
    public void deleteModel() {
        HttpDelete request = new HttpDelete(baseUri + getPkAsParams());
        HttpResponse response;
        try {
            response = client.execute(HOST, request);
        } catch (IOException ex) {
            throw new RuntimeException(ex);
        }
        StatusLine statusLine = response.getStatusLine();
        if (statusLine.getStatusCode() < 200 || statusLine.getStatusCode() > 299)
            throw new RuntimeException(statusLine.getReasonPhrase());
    }

    @Override
    @PrePassivate
    public void commitModel() {
        HttpPut request = new HttpPut(baseUri + getPkAsParams());
        request.addHeader(JSON_OUT_HEAD);
        HttpResponse response;
        try {
            request.setEntity(new InputStreamEntity(streamedMarshall()));
            response = client.execute(HOST, request);
        } catch (IOException ex) {
            throw new RuntimeException(ex);
        }
        StatusLine statusLine = response.getStatusLine();
        if (statusLine.getStatusCode() < 200 || statusLine.getStatusCode() > 299)
            throw new RuntimeException(statusLine.getReasonPhrase());
    }

}