import java.io.BufferedReader;

import java.io.BufferedWriter;

import java.io.File;

import java.io.FileNotFoundException;

import java.io.FileOutputStream;

import java.io.IOException;

import java.io.InputStreamReader;

import java.io.OutputStreamWriter;

import java.io.Writer;

import java.net.MalformedURLException;

import java.net.URL;

import java.net.URLConnection;

import java.util.Date;

import java.util.Scanner;

/**

* SimpleCache Caching Class Originally published in PHP by: Gilbert Pellegrom

* Webpage: https://github.com/gilbitron/PHP-SimpleCache

*

* Ported to Java by HiddenMotives

*

* Released under the MIT license.

* http://www.opensource.org/licenses/mit-license.php

*

*/

public final class SimpleCache {

// Cache time is defined in day intervals.

private int cache_time = 1;

// Directory where cached files will be stored

private String cache_path = "cache/";

// Extension of the cached files

private String cache_extension = ".cache";

public SimpleCache() {

this.set_cache_path(cache_path);

}

public int get_cache_time () {

return this.cache_time;

}

public String get_cache_path() {

return this.cache_path;

}

public String get_cache_extension() {

return this.cache_extension;

}

public void set_cache_time(int days) {

this.cache_time = days;

}

public void set_cache_path(String path) {

this.cache_path = path;

if (!(new File(this.cache_path).isDirectory())) {

new File(this.cache_path).mkdirs();

}

}

public void set_cache_extension(String ext) {

this.cache_extension = ext;

}

/**

* Check if a file is cached or not.

* @param label

* @return

*/

public boolean is_cached(String label) {

String filename = String.valueOf(this.cache_path)

+ this.safe_filename(label) + this.cache_extension;

File file = new File(filename);

long diff = new Date().getTime() - file.lastModified();

return file.exists() && (!(diff > (long) this.cache_time * 24 * 60 * 60

* 1000));

}

/**

* Function that allows you to grab the cache from a label.

* @param label

* @return

*/

public String get_cache(String label) {

if (this.is_cached(label)) {

String filename = String.valueOf(this.cache_path)

+ this.safe_filename(label) + this.cache_extension;

String data;

try (Scanner reader = new Scanner(new File(filename)).useDelimiter("\\Z")) {

data = reader.next();

reader.close();

return data;

} catch (FileNotFoundException e) {

return null;

}

}

return null;

}

/**

* Set a cache file using a custom label and predefined data.

* @param label

* @param data

*/

public void set_cache(String label, String data) {

try (Writer writer = new BufferedWriter(new OutputStreamWriter(

new FileOutputStream(this.cache_path

+ this.safe_filename(label) + this.cache_extension),

"utf-8"))) {

writer.write(data);

writer.close();

} catch (IOException ex) {

System.out.println(ex.getMessage());

}

}

/**

* Function that tries to cached data, if no cached file is found it will

* try and cache the data from the URL.

*

* @param label Label of the cached file

* @param url

* @return

* @throws MalformedURLException

* @throws IOException

*/

public String get_data(String label, String url)

throws MalformedURLException, IOException {

String data = null;

if (this.get_cache(label) != null) {

data = this.get_cache(label);

return data;

}

data = this.grab_url(url);

this.set_cache(label, data);

return data;

}

/**

* Function that reads and returns the contents of a URL.

* Using the specified user agent and timeout when making the URL request.

* @param url

* @param timeout in milliseconds

* @param userAgent

* @return Contents of the URL.

* @throws MalformedURLException

* @throws IOException

*/

public String grab_url(String url, int timeout, String userAgent)

throws MalformedURLException, IOException {

StringBuilder response = new StringBuilder();

URL website = new URL(url);

URLConnection connection = website.openConnection();

connection.setConnectTimeout(timeout);

connection.setRequestProperty("User-Agent", userAgent);

try (BufferedReader in = new BufferedReader(

new InputStreamReader(

connection.getInputStream()))) {

while ((url = in.readLine()) != null) {

response.append(url);

}

in.close();

}

return response.toString();

}

/**

* Function that reads and returns the contents of a URL.

* @param url

* @return Contents of the URL

* @throws MalformedURLException

* @throws IOException

*/

public String grab_url(String url) throws MalformedURLException,

IOException {

StringBuilder response = new StringBuilder();

URL website = new URL(url);

URLConnection connection = website.openConnection();

connection.setConnectTimeout(5000);

try (BufferedReader in = new BufferedReader(

new InputStreamReader(

connection.getInputStream()))) {

while ((url = in.readLine()) != null) {

response.append(url);

}

in.close();

}

return response.toString();

}

/**

* Remove all Cached files

*/

public void clearCache() {

for (File file : new File(this.cache_path).listFiles()) {

file.delete();

}

}

public void clearCache(String label) throws FileNotFoundException {

String filename = String.valueOf(this.cache_path)

+ this.safe_filename(label) + this.cache_extension;

File file = new File(filename);

if(file.exists()) {

file.delete();

} else {

throw new FileNotFoundException();

}

}

/**

* Function the number of cached files currently stored

* @return total cached files

*/

public int get_total_cached() {

return new File(this.cache_path).listFiles().length;

}

/**

* Helper function to help validate file names

* @param filename

* @return

*/

private String safe_filename(String filename) {

return filename.replaceAll("/[^0-9a-z\\.\\_\\-]/i", "");

}

}