org.springsource.ide.eclipse.commons.ui.tips.TipProvider.java Source code

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Here is the source code for org.springsource.ide.eclipse.commons.ui.tips.TipProvider.java

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/*******************************************************************************
 * Copyright (c) 2013 Pivotal Software, Inc.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     Pivotal Software, Inc. - initial API and implementation
 *******************************************************************************/
package org.springsource.ide.eclipse.commons.ui.tips;

import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Random;

import org.eclipse.core.runtime.Platform;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import org.json.JSONTokener;
import org.springsource.ide.eclipse.commons.internal.core.CorePlugin;

/**
 * Provides a list of tips o'the day
 * @author Andrew Eisenberg
 * @since 3.3.0
 */
public class TipProvider {

    private static final Random RAND = new Random();

    private TipInfo[] tips;

    private int pointer;

    private Exception error;

    public TipProvider() {
        refresh();
    }

    public void refresh() {
        error = null;
        InputStreamReader tipReader = new InputStreamReader(TipProvider.class.getClassLoader()
                .getResourceAsStream("org/springsource/ide/eclipse/commons/ui/tips/spring_tool_tips.json"));
        JSONTokener tokener = new JSONTokener(tipReader);
        List<TipInfo> tipList = Collections.emptyList();
        try {
            JSONArray json = new JSONArray(tokener);
            int length = json.length();
            tipList = new ArrayList<TipInfo>(length);
            for (int i = 0; i < length; i++) {
                JSONObject object = (JSONObject) json.get(i);
                if (object.has("required")) {
                    String requiredPlugin = object.getString("required");
                    if (Platform.getBundle(requiredPlugin) == null) {
                        continue;
                    }
                }
                tipList.add(new TipInfo(object.getString("infoText"), object.getString("linkText"),
                        object.has("keyBindingId") ? object.getString("keyBindingId") : null));
            }
        } catch (JSONException e) {
            CorePlugin.log("Error parsing tips of the day file", e);
            error = e;
        }

        if (tipList.size() == 0) {
            tips = new TipInfo[] { new TipInfo("There's a lot going on with Spring",
                    "Read the latest <a href\"http://spring.io/blog\">Spring news</a>.") };
        } else {
            tips = tipList.toArray(new TipInfo[tipList.size()]);
        }

        pointer = RAND.nextInt(tips.length);
    }

    public TipInfo nextTip() {
        return tips[(++pointer % tips.length)];
    }

    public TipInfo previousTip() {
        if (pointer == 0) {
            pointer = tips.length;
        }
        return tips[(--pointer % tips.length)];
    }

    public Exception getError() {
        return error;
    }
}