org.springframework.data.gemfire.samples.helloworld.CommandProcessor.java Source code

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Here is the source code for org.springframework.data.gemfire.samples.helloworld.CommandProcessor.java

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/*
 * Copyright 2010 the original author or authors.
 *
 * 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 org.springframework.data.gemfire.samples.helloworld;

import java.io.BufferedInputStream;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.Scanner;
import java.util.Set;
import java.util.Map.Entry;
import java.util.regex.Pattern;

import javax.annotation.Resource;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.data.gemfire.GemfireCallback;
import org.springframework.data.gemfire.GemfireTemplate;
import org.springframework.stereotype.Component;

import com.gemstone.gemfire.GemFireCheckedException;
import com.gemstone.gemfire.GemFireException;
import com.gemstone.gemfire.cache.Region;

/**
 * Entity processing and interpreting shell commands.
 * 
 * @author Costin Leau
 */
@Component
public class CommandProcessor {

    private static final Pattern COM = Pattern
            .compile("query|exit|help|size|clear|keys|values|map|containsKey|containsValue|get|remove|put");

    private static final Log log = LogFactory.getLog(CommandProcessor.class);

    private static String help = initHelp();
    private static String EMPTY = "";

    boolean threadActive;
    private Thread thread;

    @Resource
    private GemfireTemplate template;

    void start() {
        if (thread == null) {
            threadActive = true;
            thread = new Thread(new Task(), "cmd-processor");
            thread.start();
        }
    }

    void stop() throws Exception {
        threadActive = false;
        thread.join(3 * 100);
    }

    void awaitCommands() throws Exception {
        thread.join();
    }

    private class Task implements Runnable {

        public void run() {
            System.out.println("Hello World!");
            System.out.println("Want to interact with the world ? ...");
            System.out.println(help);
            System.out.print("-> ");
            System.out.flush();

            BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

            try {
                while (threadActive) {
                    if (br.ready()) {
                        try {
                            System.out.println(process(br.readLine()));
                        } catch (Exception ex) {
                            System.out.println("Error executing last command " + ex.getMessage());
                            ex.printStackTrace();
                        }

                        System.out.print("-> ");
                        System.out.flush();
                    }
                }
            } catch (IOException ioe) {
                // just ignore any exceptions
                log.error("Caught exception while processing commands ", ioe);
            }
        }
    }

    private static String initHelp() {
        try {
            InputStream stream = CommandProcessor.class.getResourceAsStream("help.txt");
            byte[] buffer = new byte[stream.available() > 0 ? stream.available() : 300];

            BufferedInputStream bf = new BufferedInputStream(stream);
            bf.read(buffer);
            return new String(buffer);
        } catch (IOException io) {
            throw new IllegalStateException("Cannot read help file");
        }
    }

    String process(final String line) {
        final Scanner sc = new Scanner(line);

        return template.execute(new GemfireCallback<String>() {

            public String doInGemfire(Region reg) throws GemFireCheckedException, GemFireException {
                Region<String, String> region = reg;

                if (!sc.hasNext(COM)) {
                    return "Invalid command - type 'help' for supported operations";
                }
                String command = sc.next();
                String arg1 = (sc.hasNext() ? sc.next() : null);
                String arg2 = (sc.hasNext() ? sc.next() : null);

                // query shortcut
                if ("query".equalsIgnoreCase(command)) {
                    String query = line.trim().substring(command.length());
                    return region.query(query).toString();
                }

                // parse commands w/o arguments
                if ("exit".equalsIgnoreCase(command)) {
                    threadActive = false;
                    return "Node exiting...";
                }
                if ("help".equalsIgnoreCase(command)) {
                    return help;
                }
                if ("size".equalsIgnoreCase(command)) {
                    return EMPTY + region.size();
                }
                if ("clear".equalsIgnoreCase(command)) {
                    region.clear();
                    return "Clearing grid..";
                }
                if ("keys".equalsIgnoreCase(command)) {
                    return region.keySet().toString();
                }
                if ("values".equalsIgnoreCase(command)) {
                    return region.values().toString();
                }

                if ("map".equalsIgnoreCase(command)) {
                    Set<Entry<String, String>> entrySet = region.entrySet();
                    if (entrySet.size() == 0)
                        return "[]";

                    StringBuilder sb = new StringBuilder();
                    for (Entry<String, String> entry : entrySet) {
                        sb.append("[");
                        sb.append(entry.getKey());
                        sb.append("=");
                        sb.append(entry.getValue());
                        sb.append("] ");
                    }
                    return sb.toString();
                }

                // commands w/ 1 arg
                if ("containsKey".equalsIgnoreCase(command)) {
                    return EMPTY + region.containsKey(arg1);
                }
                if ("containsValue".equalsIgnoreCase(command)) {
                    return EMPTY + region.containsValue(arg1);
                }
                if ("get".equalsIgnoreCase(command)) {
                    return region.get(arg1);
                }
                if ("remove".equalsIgnoreCase(command)) {
                    return region.remove(arg1);
                }

                // commands w/ 2 args

                if ("put".equalsIgnoreCase(command)) {
                    return region.put(arg1, arg2);
                }

                sc.close();
                return "unknown command - run 'help' for available commands";
            }
        });
    }
}