AutoMessagingDemo/app/src/main/java/com/example/android/automessagingdemo/Conversations.java

/*
 * Copyright (C) 2014 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.example.android.automessagingdemo;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.List;
import java.util.concurrent.ThreadLocalRandom;

/**
 * A simple class that denotes unread conversations and messages. In a real world application,
 * this would be replaced by a content provider that actually gets the unread messages to be
 * shown to the user.
 */
public class Conversations {

    /**
     * Set of strings used as messages by the sample.
     */
    private static final String[] MESSAGES = new String[]{
            "Are you at home?",
            "Can you give me a call?",
            "Hey yt?",
            "Don't forget to get some milk on your way back home",
            "Is that project done?",
            "Did you finish the Messaging app yet?"
    };

    /**
     * Senders of the said messages.
     */
    private static final String[] PARTICIPANTS = new String[]{
            "John Rambo",
            "Han Solo",
            "Rocky Balboa",
            "Lara Croft"
    };

    static class Conversation {

        private final int conversationId;

        private final String participantName;

        /**
         * A given conversation can have a single or multiple messages.
         * Note that the messages are sorted from *newest* to *oldest*
         */
        private final List<String> messages;

        private final long timestamp;

        public Conversation(int conversationId, String participantName,
                            List<String> messages) {
            this.conversationId = conversationId;
            this.participantName = participantName;
            this.messages = messages == null ? Collections.<String>emptyList() : messages;
            this.timestamp = System.currentTimeMillis();
        }

        public int getConversationId() {
            return conversationId;
        }

        public String getParticipantName() {
            return participantName;
        }

        public List<String> getMessages() {
            return messages;
        }

        public long getTimestamp() {
            return timestamp;
        }

        public String toString() {
            return "[Conversation: conversationId=" + conversationId +
                    ", participantName=" + participantName +
                    ", messages=" + messages +
                    ", timestamp=" + timestamp + "]";
        }
    }

    private Conversations() {
    }

    public static Conversation[] getUnreadConversations(int howManyConversations,
                                                        int messagesPerConversation) {
        Conversation[] conversations = new Conversation[howManyConversations];
        for (int i = 0; i < howManyConversations; i++) {
            conversations[i] = new Conversation(
                    ThreadLocalRandom.current().nextInt(),
                    name(), makeMessages(messagesPerConversation));
        }
        return conversations;
    }

    private static List<String> makeMessages(int messagesPerConversation) {
        int maxLen = MESSAGES.length;
        List<String> messages = new ArrayList<>(messagesPerConversation);
        for (int i = 0; i < messagesPerConversation; i++) {
            messages.add(MESSAGES[ThreadLocalRandom.current().nextInt(0, maxLen)]);
        }
        return messages;
    }

    private static String name() {
        return PARTICIPANTS[ThreadLocalRandom.current().nextInt(0, PARTICIPANTS.length)];
    }
}