com.ibm.streamsx.rest.Element.java Source code

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Here is the source code for com.ibm.streamsx.rest.Element.java

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/*
# Licensed Materials - Property of IBM
# Copyright IBM Corp. 2017
 */
package com.ibm.streamsx.rest;

import java.io.IOException;
import java.lang.reflect.Type;

import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
import com.google.gson.InstanceCreator;
import com.google.gson.annotations.Expose;

/**
 * IBM Streams element.
 *
 * Super-class for elements returned from the IBM Streams REST API.
 */
public abstract class Element {

    static final GsonBuilder refreshBuilder = new GsonBuilder().excludeFieldsWithoutExposeAnnotation();
    static final Gson gson = new GsonBuilder().excludeFieldsWithoutExposeAnnotation().create();

    private static final Gson pretty = new GsonBuilder().excludeFieldsWithoutExposeAnnotation().setPrettyPrinting()
            .create();

    private AbstractStreamsConnection connection;

    @Expose
    private String self;

    AbstractStreamsConnection connection() {
        return connection;
    }

    String self() {
        return self;
    }

    void setConnection(AbstractStreamsConnection connection) {
        this.connection = connection;
    }

    void setConnection(AbstractStreamsConnection connection, String self) {
        this.connection = connection;
        this.self = self;
    }

    @Override
    public final String toString() {
        return pretty.toJson(this);
    }

    private Gson refreshJson;

    /**
     * Refresh this element.
     * 
     * Attributes of this object are updated from current state
     * though the Streams REST API.
     * 
     * @throws IOException Error communicating with Streams.
     */
    public void refresh() throws IOException {
        String response = connection().getResponseString(self);

        if (refreshJson == null) {
            refreshJson = refreshBuilder.registerTypeAdapter(getClass(), new InstanceCreator<Object>() {
                @Override
                public Object createInstance(Type arg0) {
                    return Element.this;
                }
            }).create();
        }

        Object me = refreshJson.fromJson(response, getClass());

        assert me == this;
    }
}