Class Util

java.lang.Object
com.codename1.io.Util
public final class Util extends Object
Various utility methods used for HTTP/IO operations

  • Method Details

    • getIgnorCharsWhileEncoding

      public static String getIgnorCharsWhileEncoding()

      These chars will not be encoded by the encoding method in this class as requested in RFE 427 http://java.net/jira/browse/LWUIT-427

      Returns

      chars skipped

    • setIgnorCharsWhileEncoding

      public static void setIgnorCharsWhileEncoding(String s)

      These chars will not be encoded by the encoding method in this class as requested in RFE 427 http://java.net/jira/browse/LWUIT-427

      Parameters
      • s: set of characters to skip when encoding

    • getReader

      public static InputStreamReader getReader(InputStream in)

      Helper to get a reader from an input stream with UTF-8 encoding

      Parameters
      • in: the input stream
      Returns

      the reader

    • getWriter

      public static OutputStreamWriter getWriter(OutputStream out)

      Helper to get a writer from an output stream with UTF-8 encoding

      Parameters
      • out: the output stream
      Returns

      the writer

    • copy

      public static void copy(InputStream i, OutputStream o) throws IOException

      Copy the input stream into the output stream, closes both streams when finishing or in a case of an exception

      Parameters

      • i: source

      • o: destination

      Throws:
      IOException

    • copyNoClose

      public static void copyNoClose(InputStream i, OutputStream o, int bufferSize) throws IOException

      Copy the input stream into the output stream, without closing the streams when done

      Parameters

      • i: source

      • o: destination

      • bufferSize: the size of the buffer, which should be a power of 2 large enough

      Throws:
      IOException

    • copyNoClose

      public static void copyNoClose(InputStream i, OutputStream o, int bufferSize, IOProgressListener callback) throws IOException

      Copy the input stream into the output stream, without closing the streams when done

      Parameters

      • i: source

      • o: destination

      • bufferSize: the size of the buffer, which should be a power of 2 large enough

      • callback: called after each copy step

      Throws:
      IOException

    • copy

      public static void copy(InputStream i, OutputStream o, int bufferSize) throws IOException

      Copy the input stream into the output stream, closes both streams when finishing or in a case of an exception

      Parameters

      • i: source

      • o: destination

      • bufferSize: the size of the buffer, which should be a power of 2 large enough

      Throws:
      IOException

    • cleanup

      public static void cleanup(Object o)

      Closes the object (connection, stream etc.) without throwing any exception, even if the object is null

      Parameters
      • o: Connection, Stream or other closeable object

    • readToString

      public static String readToString(InputStream i) throws IOException

      Reads an input stream to a string

      Parameters
      • i: the input stream
      Returns

      a UTF-8 string

      Throws
      • IOException: thrown by the stream
      Throws:
      IOException

    • readToString

      public static String readToString(File file, String charset) throws IOException

      Reads the contents of a file to a string.

      Parameters

      • file: The file to read.

      • charset: The Charset to use to write the file.

      Returns

      The string read from the file.

      Throws
      • IOException: If the file does not exist, or cannot be read for some reason.
      Since

      8.0

      Throws:
      IOException

    • readToString

      public static String readToString(File file) throws IOException

      Reads the contents of a file to a string. Uses UTF-8 encoding.

      Parameters
      • file: The file to read.
      Returns

      The string read from the file.

      Throws
      • IOException: If the file does not exist, or cannot be read for some reason.
      Since

      8.0

      Throws:
      IOException

    • writeStringToFile

      public static void writeStringToFile(File file, String contents) throws IOException

      Writes a string to a file using UTF-8 encoding.

      Parameters

      • file: The file to write to.

      • contents: The contents to write to the file.

      Throws
      • IOException: If it cannot write to the file for some reason.
      Since

      8.0

      Throws:
      IOException

    • writeStringToFile

      public static void writeStringToFile(File file, String contents, String charset) throws IOException

      Writes a string to a file.

      Parameters

      • file: The file to write to.

      • contents: The contents to write to the file.

      • charset: The charset to use. If null, it defaults to UTF-8

      Throws
      • IOException: If it cannot write to the file for some reason.
      Since

      8.0

      Throws:
      IOException

    • readToString

      public static String readToString(InputStream i, String encoding) throws IOException

      Reads an input stream to a string

      Parameters

      • i: the input stream

      • encoding: the encoding of the stream

      Returns

      a string

      Throws
      • IOException: thrown by the stream
      Throws:
      IOException

    • readToString

      public static String readToString(Reader reader) throws IOException

      Reads a reader to a string

      Parameters

      • i: the input stream

      • encoding: the encoding of the stream

      Returns

      a string

      Throws
      • IOException: thrown by the stream
      Since

      7.0

      Throws:
      IOException

    • readInputStream

      public static byte[] readInputStream(InputStream i) throws IOException

      Converts a small input stream to a byte array

      Parameters
      • i: the stream to convert
      Returns

      byte array of the content of the stream

      Throws:
      IOException

    • register

      public static void register(Externalizable e)

      Registers this externalizable so readObject will be able to load such objects.

      The sample below demonstrates the usage and registration of the com.codename1.io.Externalizable interface:

      // File: Main.java
public Main {
  public void init(Object o) {
    theme = UIManager.initFirstTheme("/theme");

    // IMPORTANT: Notice we don't use MyClass.class.getName()! This won't work due to obfuscation!
    Util.register("MyClass", MyClass.class);
  }

  public void start() {
    //...
  }

  public void stop() {
    //...
  }

  public void destroy() {
    //...
  }
}

      // File: MyClass.java
public MyClass implements Externalizable {
  // allows us to manipulate the version, in this case we are demonstrating a data change between the initial release
  // and the current state of object data
  private static final int VERSION = 2;

  private String name;
  private Map data;

  // this field was added after version 1
  private Date startedAt;

  public int getVersion() {
    return VERSION;
  }

  public void externalize(DataOutputStream out) throws IOException {
    Util.writeUTF(name, out);
    Util.writeObject(data, out);
    if(startedAt != null) {
        out.writeBoolean(true);
        out.writeLong(startedAt.getTime());
    } else {
        out.writeBoolean(false);
    }
  }
  public void internalize(int version, DataInputStream in) throws IOException {
    name = Util.readUTF(in);
    data = (Map)Util.readObject(in);
    if(version > 1) {
        boolean hasDate = in.readBoolean();
        if(hasDate) {
            startedAt = new Date(in.readLong());
        }
    }
  }
  public String getObjectId() {
    // IMPORTANT: Notice we don't use getClass().getName()! This won't work due to obfuscation!
    return "MyClass";
  }
}

      // File: ReadAndWrite.java
// will read the file or return null if failed
MyClass object = (MyClass)Storage.getInstance().readObject("NameOfFile");

// write the object back to storage
Storage.getInstance().writeObject("NameOfFile", object);
      Parameters
      • e: the externalizable instance

    • register

      public static void register(String id, Class c)

      Registers this externalizable so readObject will be able to load such objects.

      The sample below demonstrates the usage and registration of the com.codename1.io.Externalizable interface:

      // File: Main.java
public Main {
  public void init(Object o) {
    theme = UIManager.initFirstTheme("/theme");

    // IMPORTANT: Notice we don't use MyClass.class.getName()! This won't work due to obfuscation!
    Util.register("MyClass", MyClass.class);
  }

  public void start() {
    //...
  }

  public void stop() {
    //...
  }

  public void destroy() {
    //...
  }
}

      // File: MyClass.java
public MyClass implements Externalizable {
  // allows us to manipulate the version, in this case we are demonstrating a data change between the initial release
  // and the current state of object data
  private static final int VERSION = 2;

  private String name;
  private Map data;

  // this field was added after version 1
  private Date startedAt;

  public int getVersion() {
    return VERSION;
  }

  public void externalize(DataOutputStream out) throws IOException {
    Util.writeUTF(name, out);
    Util.writeObject(data, out);
    if(startedAt != null) {
        out.writeBoolean(true);
        out.writeLong(startedAt.getTime());
    } else {
        out.writeBoolean(false);
    }
  }
  public void internalize(int version, DataInputStream in) throws IOException {
    name = Util.readUTF(in);
    data = (Map)Util.readObject(in);
    if(version > 1) {
        boolean hasDate = in.readBoolean();
        if(hasDate) {
            startedAt = new Date(in.readLong());
        }
    }
  }
  public String getObjectId() {
    // IMPORTANT: Notice we don't use getClass().getName()! This won't work due to obfuscation!
    return "MyClass";
  }
}

      // File: ReadAndWrite.java
// will read the file or return null if failed
MyClass object = (MyClass)Storage.getInstance().readObject("NameOfFile");

// write the object back to storage
Storage.getInstance().writeObject("NameOfFile", object);
      Parameters

      • id: id of the externalizable

      • c: the class for the externalizable

    • writeObject

      public static void writeObject(Object o, DataOutputStream out) throws IOException

      Writes an object to the given output stream, notice that it should be externalizable or one of the supported types.

      The sample below demonstrates the usage and registration of the com.codename1.io.Externalizable interface:

      // File: Main.java
public Main {
  public void init(Object o) {
    theme = UIManager.initFirstTheme("/theme");

    // IMPORTANT: Notice we don't use MyClass.class.getName()! This won't work due to obfuscation!
    Util.register("MyClass", MyClass.class);
  }

  public void start() {
    //...
  }

  public void stop() {
    //...
  }

  public void destroy() {
    //...
  }
}

      // File: MyClass.java
public MyClass implements Externalizable {
  // allows us to manipulate the version, in this case we are demonstrating a data change between the initial release
  // and the current state of object data
  private static final int VERSION = 2;

  private String name;
  private Map data;

  // this field was added after version 1
  private Date startedAt;

  public int getVersion() {
    return VERSION;
  }

  public void externalize(DataOutputStream out) throws IOException {
    Util.writeUTF(name, out);
    Util.writeObject(data, out);
    if(startedAt != null) {
        out.writeBoolean(true);
        out.writeLong(startedAt.getTime());
    } else {
        out.writeBoolean(false);
    }
  }
  public void internalize(int version, DataInputStream in) throws IOException {
    name = Util.readUTF(in);
    data = (Map)Util.readObject(in);
    if(version > 1) {
        boolean hasDate = in.readBoolean();
        if(hasDate) {
            startedAt = new Date(in.readLong());
        }
    }
  }
  public String getObjectId() {
    // IMPORTANT: Notice we don't use getClass().getName()! This won't work due to obfuscation!
    return "MyClass";
  }
}

      // File: ReadAndWrite.java
// will read the file or return null if failed
MyClass object = (MyClass)Storage.getInstance().readObject("NameOfFile");

// write the object back to storage
Storage.getInstance().writeObject("NameOfFile", object);
      Parameters

      • o: the object to write which can be null

      • out: the destination output stream

      Throws
      • IOException: thrown by the stream
      Throws:
      IOException

    • instanceofObjArray

      public static boolean instanceofObjArray(Object o)

      This method allows working around issue 58

      Parameters
      • o: object to test
      Returns

      true if it matches the state

      Deprecated

    • instanceofByteArray

      public static boolean instanceofByteArray(Object o)

      This method allows working around issue 58

      Parameters
      • o: object to test
      Returns

      true if it matches the state

      Deprecated

    • instanceofShortArray

      public static boolean instanceofShortArray(Object o)

      This method allows working around issue 58

      Parameters
      • o: object to test
      Returns

      true if it matches the state

      Deprecated

    • instanceofLongArray

      public static boolean instanceofLongArray(Object o)

      This method allows working around issue 58

      Parameters
      • o: object to test
      Returns

      true if it matches the state

      Deprecated

    • instanceofIntArray

      public static boolean instanceofIntArray(Object o)

      This method allows working around issue 58

      Parameters
      • o: object to test
      Returns

      true if it matches the state

      Deprecated

    • instanceofFloatArray

      public static boolean instanceofFloatArray(Object o)

      This method allows working around issue 58

      Parameters
      • o: object to test
      Returns

      true if it matches the state

      Deprecated

    • instanceofDoubleArray

      public static boolean instanceofDoubleArray(Object o)

      This method allows working around issue 58

      Parameters
      • o: object to test
      Returns

      true if it matches the state

      Deprecated

    • readObject

      public static Object readObject(DataInputStream input) throws IOException

      Reads an object from the stream, notice that this is the inverse of the java.io.DataOutputStream).

      The sample below demonstrates the usage and registration of the com.codename1.io.Externalizable interface:

      // File: Main.java
public Main {
  public void init(Object o) {
    theme = UIManager.initFirstTheme("/theme");

    // IMPORTANT: Notice we don't use MyClass.class.getName()! This won't work due to obfuscation!
    Util.register("MyClass", MyClass.class);
  }

  public void start() {
    //...
  }

  public void stop() {
    //...
  }

  public void destroy() {
    //...
  }
}

      // File: MyClass.java
public MyClass implements Externalizable {
  // allows us to manipulate the version, in this case we are demonstrating a data change between the initial release
  // and the current state of object data
  private static final int VERSION = 2;

  private String name;
  private Map data;

  // this field was added after version 1
  private Date startedAt;

  public int getVersion() {
    return VERSION;
  }

  public void externalize(DataOutputStream out) throws IOException {
    Util.writeUTF(name, out);
    Util.writeObject(data, out);
    if(startedAt != null) {
        out.writeBoolean(true);
        out.writeLong(startedAt.getTime());
    } else {
        out.writeBoolean(false);
    }
  }
  public void internalize(int version, DataInputStream in) throws IOException {
    name = Util.readUTF(in);
    data = (Map)Util.readObject(in);
    if(version > 1) {
        boolean hasDate = in.readBoolean();
        if(hasDate) {
            startedAt = new Date(in.readLong());
        }
    }
  }
  public String getObjectId() {
    // IMPORTANT: Notice we don't use getClass().getName()! This won't work due to obfuscation!
    return "MyClass";
  }
}

      // File: ReadAndWrite.java
// will read the file or return null if failed
MyClass object = (MyClass)Storage.getInstance().readObject("NameOfFile");

// write the object back to storage
Storage.getInstance().writeObject("NameOfFile", object);
      Parameters
      • input: the source input stream
      Throws
      • IOException: thrown by the stream
      Throws:
      IOException

    • encodeUrl

      public static String encodeUrl(String str)

      Encode a string for HTML requests

      Parameters
      • str: none encoded string
      Returns

      encoded string

    • encodeUrl

      public static String encodeUrl(String str, String doNotEncodeChars)

      Encodes the provided string as a URL (with %20 for spaces).

      Parameters

      • str: The URL to encode

      • doNotEncodeChars: A string whose characters will not be encoded.

    • toCharArray

      public static char[] toCharArray(String s)

      toCharArray should return a new array always, however some devices might suffer a bug that allows mutating a String (serious security hole in the JVM) hence this method simulates the proper behavior

      Parameters
      • s: a string
      Returns

      the contents of the string as a char array guaranteed to be a copy of the current array

    • decode

      public static String decode(String s, String enc, boolean plusToSpace)

      Decodes a String URL encoded URL

      Parameters

      • s: the string

      • enc: the encoding (defaults to UTF-8 if null)

      • plusToSpace: true if plus signs be converted to spaces

      Returns

      a decoded string

    • encodeBody

      public static String encodeBody(String str)

      Encode a string for HTML post requests matching the style used in application/x-www-form-urlencoded

      Parameters
      • str: none encoded string
      Returns

      encoded string

    • encodeUrl

      public static String encodeUrl(byte[] buf)

      Encode a string for HTML requests

      Parameters
      • buf: none encoded string
      Returns

      encoded string

      Deprecated

      use encodeUrl(char[]) instead

    • encodeUrl

      public static String encodeUrl(char[] buf)

      Encode a string for HTML requests

      Parameters
      • buf: none encoded string
      Returns

      encoded string

    • encodeBody

      public static String encodeBody(char[] buf)

      Encode a string for HTML post requests matching the style used in application/x-www-form-urlencoded

      Parameters
      • buf: none encoded string
      Returns

      encoded string

    • encodeBody

      public static String encodeBody(byte[] buf)

      Encode a string for HTML post requests matching the style used in application/x-www-form-urlencoded

      Parameters
      • buf: none encoded string
      Returns

      encoded string

      Deprecated

      use encodeUrl(char[]) instead

    • relativeToAbsolute

      public static String relativeToAbsolute(String baseURL, String relativeURL)

      Converts a relative url e.g.: /myfile.html to an absolute url

      Parameters

      • baseURL: a source URL whose properties should be used to construct the actual URL

      • relativeURL: relative address

      Returns

      an absolute URL

    • getURLProtocol

      public static String getURLProtocol(String url)

      Returns the protocol of an absolute URL e.g. http, https etc.

      Parameters
      • url: absolute URL
      Returns

      protocol

    • getURLHost

      public static String getURLHost(String url)

      Returns the URL's host portion

      Parameters
      • url: absolute URL
      Returns

      the domain of the URL

    • getURLPath

      public static String getURLPath(String url)

      Returns the URL's path

      Parameters
      • url: absolute URL
      Returns

      the path within the host

    • getURLBasePath

      public static String getURLBasePath(String url)

      Returns the URL's base path, which is the same as the path only without an ending file e.g.: http://domain.com/f/f.html would return as: /f/

      Parameters
      • url: absolute URL
      Returns

      the path within the host

    • writeUTF

      public static void writeUTF(String s, DataOutputStream d) throws IOException

      Writes a string with a null flag, this allows a String which may be null

      Parameters

      • s: the string to write

      • d: the destination output stream

      Throws
      • java.io.IOException
      Throws:
      IOException

    • readUTF

      public static String readUTF(DataInputStream d) throws IOException

      Reads a UTF string that may be null previously written by writeUTF

      Parameters
      • d: the stream
      Returns

      a string or null

      Throws
      • java.io.IOException
      Throws:
      IOException

    • readFully

      public static void readFully(InputStream i, byte[] b) throws IOException

      The read fully method from data input stream is very useful for all types of streams...

      Parameters
      • b: the buffer into which the data is read.
      Throws
      • IOException: @throws IOException the stream has been closed and the contained input stream does not support reading after close, or another I/O error occurs.
      Throws:
      IOException

    • readFully

      public static void readFully(InputStream i, byte[] b, int off, int len) throws IOException

      The read fully method from data input stream is very useful for all types of streams...

      Parameters

      • b: the buffer into which the data is read.

      • off: the start offset of the data.

      • len: the number of bytes to read.

      Throws
      • IOException: @throws IOException the stream has been closed and the contained input stream does not support reading after close, or another I/O error occurs.
      Throws:
      IOException

    • readAll

      public static int readAll(InputStream i, byte[] b) throws IOException

      Reads until the array is full or until the stream ends

      Parameters
      • b: the buffer into which the data is read.
      Returns

      the amount read

      Throws
      • IOException: @throws IOException the stream has been closed and the contained input stream does not support reading after close, or another I/O error occurs.
      Throws:
      IOException

    • split

      public static String[] split(String original, String separator)

      Provides a utility method breaks a given String to array of String according to the given separator

      Parameters

      • original: the String to break

      • separator: the pattern to look in the original String

      Returns

      array of Strings from the original String

    • setImplementation

      public static void setImplementation(CodenameOneImplementation impl)

      Invoked internally from Display, this method is for internal use only

      Parameters
      • impl: implementation instance

    • mergeArrays

      public static void mergeArrays(Object[] arr1, Object[] arr2, Object[] destinationArray)
      Merges arrays into one larger array

    • removeObjectAtOffset

      public static void removeObjectAtOffset(Object[] sourceArray, Object[] destinationArray, Object o)

      Removes the object at the source array offset and copies all other objects to the destination array

      Parameters

      • sourceArray: the source array

      • destinationArray: the resulting array which should be of the length sourceArray.length - 1

      • o: the object to remove from the array

    • removeObjectAtOffset

      public static void removeObjectAtOffset(Object[] sourceArray, Object[] destinationArray, int offset)

      Removes the object at the source array offset and copies all other objects to the destination array

      Parameters

      • sourceArray: the source array

      • destinationArray: the resulting array which should be of the length sourceArray.length - 1

      • offset: the offset of the array

    • insertObjectAtOffset

      public static void insertObjectAtOffset(Object[] sourceArray, Object[] destinationArray, int offset, Object o)

      Inserts the object at the destination array offset

      Parameters

      • sourceArray: the source array

      • destinationArray: the resulting array which should be of the length sourceArray.length + 1

      • offset: the offset of the array

      • o: the object

    • indexOf

      public static int indexOf(Object[] arr, Object value)

      Finds the object at the given offset while using the == operator and not the equals method call, it doesn't rely on the ordering of the elements like the Arrays method.

      Parameters

      • arr: the array

      • value: the value to search

      Returns

      the offset or -1

    • downloadUrlToStorage

      public static boolean downloadUrlToStorage(String url, String fileName, boolean showProgress)

      Blocking method that will download the given URL to storage and return when the operation completes

      Parameters

      • url: the URL

      • fileName: the storage file name

      • showProgress: whether to block the UI until download completes/fails

      Returns

      true on success false on error

    • downloadUrlToFile

      public static boolean downloadUrlToFile(String url, String fileName, boolean showProgress)

      Blocking method that will download the given URL to the file system storage and return when the operation completes

      Parameters

      • url: the URL

      • fileName: the file name

      • showProgress: whether to block the UI until download completes/fails

      Returns

      true on success false on error

    • downloadUrlToStorageInBackground

      public static void downloadUrlToStorageInBackground(String url, String fileName)

      Non-blocking method that will download the given URL to storage in the background and return immediately. This method can be used to fetch data dynamically and asynchronously e.g. in this code it is used to fetch book covers for the com.codename1.components.ImageViewer:

      Form hi = new Form("ImageViewer", new BorderLayout());
final EncodedImage placeholder = EncodedImage.createFromImage(
        FontImage.createMaterial(FontImage.MATERIAL_SYNC, s).
                scaled(300, 300), false);

class ImageList implements ListModel {
    private int selection;
    private String[] imageURLs = {
        "http://awoiaf.westeros.org/images/thumb/9/93/AGameOfThrones.jpg/300px-AGameOfThrones.jpg",
        "http://awoiaf.westeros.org/images/thumb/3/39/AClashOfKings.jpg/300px-AClashOfKings.jpg",
        "http://awoiaf.westeros.org/images/thumb/2/24/AStormOfSwords.jpg/300px-AStormOfSwords.jpg",
        "http://awoiaf.westeros.org/images/thumb/a/a3/AFeastForCrows.jpg/300px-AFeastForCrows.jpg",
        "http://awoiaf.westeros.org/images/7/79/ADanceWithDragons.jpg"
    };
    private Image[] images;
    private EventDispatcher listeners = new EventDispatcher();

    public ImageList() {
        this.images = new EncodedImage[imageURLs.length];
    }

    public Image getItemAt(final int index) {
        if(images[index] == null) {
            images[index] = placeholder;
            Util.downloadUrlToStorageInBackground(imageURLs[index], "list" + index, (e) -> {
                    try {
                        images[index] = EncodedImage.create(Storage.getInstance().createInputStream("list" + index));
                        listeners.fireDataChangeEvent(index, DataChangedListener.CHANGED);
                    } catch(IOException err) {
                        err.printStackTrace();
                    }
            });
        }
        return images[index];
    }

    public int getSize() {
        return imageURLs.length;
    }

    public int getSelectedIndex() {
        return selection;
    }

    public void setSelectedIndex(int index) {
        selection = index;
    }

    public void addDataChangedListener(DataChangedListener l) {
        listeners.addListener(l);
    }

    public void removeDataChangedListener(DataChangedListener l) {
        listeners.removeListener(l);
    }

    public void addSelectionListener(SelectionListener l) {
    }

    public void removeSelectionListener(SelectionListener l) {
    }

    public void addItem(Image item) {
    }

    public void removeItem(int index) {
    }
};

ImageList imodel = new ImageList();

ImageViewer iv = new ImageViewer(imodel.getItemAt(0));
iv.setImageList(imodel);
hi.add(BorderLayout.CENTER, iv);
      Parameters

      • url: the URL

      • fileName: the storage file name

    • downloadUrlToFileSystemInBackground

      public static void downloadUrlToFileSystemInBackground(String url, String fileName)

      Non-blocking method that will download the given URL to file system storage in the background and return immediately

      Parameters

      • url: the URL

      • fileName: the file name

    • downloadUrlToStorageInBackground

      public static void downloadUrlToStorageInBackground(String url, String fileName, ActionListener onCompletion)

      Non-blocking method that will download the given URL to storage in the background and return immediately

      Parameters

      • url: the URL

      • fileName: the storage file name

      • onCompletion: invoked when download completes

    • downloadUrlToFileSystemInBackground

      public static void downloadUrlToFileSystemInBackground(String url, String fileName, ActionListener onCompletion)

      Non-blocking method that will download the given URL to file system storage in the background and return immediately

      Parameters

      • url: the URL

      • fileName: the file name

      • onCompletion: invoked when download completes

    • downloadImageToFileSystem

      public static void downloadImageToFileSystem(String url, String fileName, SuccessCallback<Image> onSuccess, FailureCallback<Image> onFail)

      Downloads an image to the file system asynchronously. If the image is already downloaded it will just load it directly from the file system.

      Parameters

      • url: The URL to download the image from.

      • fileName: @param fileName The the path to the file where the image should be downloaded. If this file already exists, it will simply load this file and skip the network request altogether.

      • onSuccess: Callback called on success.

      • onFail: Callback called if we fail to load the image.

      Since

      3.4

      See also
      • ConnectionRequest#downloadImageToFileSystem(java.lang.String, com.codename1.util.SuccessCallback, com.codename1.util.FailureCallback)

    • downloadImageToFileSystem

      public static AsyncResource<Image> downloadImageToFileSystem(String url, String fileName)

      Downloads an image to the file system asynchronously. If the image is already downloaded it will just load it directly from the file system.

      Parameters

      • url: The URL to download the image from.

      • fileName: @param fileName The the path to the file where the image should be downloaded. If this file already exists, it will simply load this file and skip the network request altogether.

      Since

      7.0

      See also
      • ConnectionRequest#downloadImageToFileSystem(java.lang.String, com.codename1.util.SuccessCallback, com.codename1.util.FailureCallback)

    • downloadImageToFileSystem

      public static void downloadImageToFileSystem(String url, String fileName, SuccessCallback<Image> onSuccess)

      Downloads an image to the file system asynchronously. If the image is already downloaded it will just load it directly from the file system.

      Parameters

      • url: The URL to download the image from.

      • fileName: @param fileName The the path to the file where the image should be downloaded. If this file already exists, it will simply load this file and skip the network request altogether.

      • onSuccess: Callback called on success.

      Since

      3.4

      See also
      • ConnectionRequest#downloadImageToFileSystem(java.lang.String, com.codename1.util.SuccessCallback)

    • downloadImageToStorage

      public static void downloadImageToStorage(String url, String fileName, SuccessCallback<Image> onSuccess, FailureCallback<Image> onFail)

      Downloads an image to storage asynchronously. If the image is already downloaded it will just load it directly from storage.

      Parameters

      • url: The URL to download the image from.

      • fileName: @param fileName The the storage file to save the image to. If this file already exists, it will simply load this file and skip the network request altogether.

      • onSuccess: Callback called on success.

      • onFail: Callback called if we fail to load the image.

      Since

      3.4

      See also
      • ConnectionRequest#downloadImageToStorage(java.lang.String, com.codename1.util.SuccessCallback, com.codename1.util.FailureCallback)

    • downloadImageToStorage

      public static AsyncResource<Image> downloadImageToStorage(String url, String fileName)

      Downloads an image to storage asynchronously. If the image is already downloaded it will just load it directly from storage.

      Parameters

      • url: The URL to download the image from.

      • fileName: @param fileName The the storage file to save the image to. If this file already exists, it will simply load this file and skip the network request altogether.

      Since

      7.0

      See also
      • ConnectionRequest#downloadImageToStorage(java.lang.String, com.codename1.util.SuccessCallback, com.codename1.util.FailureCallback)

    • downloadImageToCache

      public static void downloadImageToCache(String url, SuccessCallback<Image> onSuccess, FailureCallback<Image> onFail)

      Downloads an image to the cache asynchronously.

      Parameters

      • url: The URL to download.

      • onSuccess: Callback to run on successful completion.

      • onFail: Callback to run if download fails.

    • downloadImageToCache

      public static AsyncResource<Image> downloadImageToCache(String url)

      Downloads an image to the cache asynchronously.

      Parameters
      • url: The URL of the image to download.
      Returns

      AsyncResource to wrap the Image.

      Since

      7.0

    • downloadImageToStorage

      public static void downloadImageToStorage(String url, String fileName, SuccessCallback<Image> onSuccess)

      Downloads an image to storage asynchronously. If the image is already downloaded it will just load it directly from storage.

      Parameters

      • url: The URL to download the image from.

      • fileName: @param fileName The the storage file to save the image to. If this file already exists, it will simply load this file and skip the network request altogether.

      • onSuccess: Callback called on success.

      Since

      3.4

      See also
      • ConnectionRequest#downloadImageToStorage(java.lang.String, com.codename1.util.SuccessCallback)

    • sleep

      public static void sleep(int t)

      Shorthand method for Thread sleep that doesn't throw the stupid interrupted checked exception

      Parameters
      • t: the time

    • wait

      public static void wait(Object o, int t)

      Shorthand method wait method that doesn't throw the stupid interrupted checked exception, it also includes the synchronized block to further reduce code clutter

      Parameters

      • o: the object to wait on

      • t: the time

    • wait

      public static void wait(Object o)

      Shorthand method wait method that doesn't throw the stupid interrupted checked exception, it also includes the synchronized block to further reduce code clutter

      Parameters
      • o: the object to wait on

    • toBooleanValue

      public static boolean toBooleanValue(Object val)

      Returns true or false based on a "soft" object

      Parameters
      • val: a boolean value as a Boolean object, String or number
      Returns

      true or false

    • toIntValue

      public static int toIntValue(Object number)

      Returns the number object as an int

      Parameters
      • number: this can be a String or any number type
      Returns

      an int value or an exception

    • toLongValue

      public static long toLongValue(Object number)

      Returns the number object as a long

      Parameters
      • number: this can be a String or any number type
      Returns

      a long value or an exception

    • toFloatValue

      public static float toFloatValue(Object number)

      Returns the number object as a float

      Parameters
      • number: this can be a String or any number type
      Returns

      a float value or an exception

    • toDoubleValue

      public static double toDoubleValue(Object number)

      Returns the number object as a double

      Parameters
      • number: this can be a String or any number type
      Returns

      a double value or an exception

    • setDateFormatter

      public static void setDateFormatter(SimpleDateFormat formatter)

      Sets a custom formatter to use when toDateValue is invoked

      Parameters
      • formatter: the formatter to use

    • toDateValue

      public static Date toDateValue(Object o)

      Tries to convert an arbitrary object to a date

      Parameters
      • o: an object that can be a string, number or date
      Returns

      a Date object

    • xorDecode

      public static String xorDecode(String s)

      Encodes a string in a way that makes it harder to read it "as is" this makes it possible for Strings to be "encoded" within the app and thus harder to discover by a casual search.

      Parameters
      • s: the string to decode
      Returns

      the decoded string

    • xorEncode

      public static String xorEncode(String s)

      The inverse method of xorDecode, this is normally unnecessary and is here mostly for completeness

      Parameters
      • s: a regular string
      Returns

      a String that can be used in the xorDecode method

    • guessMimeType

      public static String guessMimeType(String sourceFile) throws IOException

      Tries to determine the mime type of a file based on its first bytes.Direct inspection of the bytes to determine the content type is often more accurate than believing the content type claimed by the http server or by the file extension.

      Parameters
      • sourceFile,: @param sourceFile, it automatically choose Storage API or FileSystemStorage API
      Returns
      Returns:

      the detected mime type, or "application/octet-stream" if the type is not detected

      Throws
      • IOException
      Throws:
      IOException

    • guessMimeType

      public static String guessMimeType(InputStream in) throws IOException

      Tries to determine the mime type of an InputStream based on its first bytes.Direct inspection of the bytes to determine the content type is often more accurate than believing the content type claimed by the http server or by the file extension.

      Parameters
      • in
      Returns
      Returns:

      the detected mime type, or "application/octet-stream" if the type is not detected

      Throws
      • IOException
      Throws:
      IOException

    • guessMimeType

      public static String guessMimeType(byte[] data)

      Tries to determine the mime type of a byte array based on its first bytes.Direct inspection of the bytes to determine the content type is often more accurate than believing the content type claimed by the http server or by the file extension.

      Parameters
      • data
      Returns
      Returns:
      the detected mime type, or "application/octet-stream" if the type is not detected

    • getFileSizeWithoutDownload

      public static long getFileSizeWithoutDownload(String url)

      Returns -1 if the content length is unknown, a value greater than 0 if the Content-Length is known.

      Parameters
      • url
      Returns

      Content-Length if known

    • getFileSizeWithoutDownload

      public static long getFileSizeWithoutDownload(String url, boolean checkPartialDownloadSupport)

      Returns -2 if the server doesn't accept partial downloads (and if checkPartialDownloadSupport is true), -1 if the content length is unknow, a value greater than 0 if the Content-Length is known.

      Parameters

      • url

      • checkPartialDownloadSupport: @param checkPartialDownloadSupport if true returns -2 if the server doesn't accept partial downloads.

      Returns

      Content-Length if known

    • downloadUrlSafely

      public static void downloadUrlSafely(String url, String fileName, OnComplete<Integer> percentageCallback, OnComplete<String> filesavedCallback) throws IOException

      Safely download the given URL to the Storage or to the FileSystemStorage: this method is resistant to network errors and capable of resume the download as soon as network conditions allow and in a completely transparent way for the user; note that in the global network error handling, there must be an automatic

      .retry()

      , as in the code example below.

      This method is useful if the server correctly returns Content-Length and if it supports partial downloads: if not, it works like a normal download.

      Pros: always allows you to complete downloads, even if very heavy (e.g. 100MB), even if the connection is unstable (network errors) and even if the app goes temporarily in the background (on some platforms the download will continue in the background, on others it will be temporarily suspended).

      Cons: since this method is based on splitting the download into small parts (512kbytes is the default), this approach causes many GET requests that slightly slow down the download and cause more traffic than normally needed.

      Usage example:

      import com.codename1.components.SpanLabel;
import com.codename1.components.ToastBar;
import static com.codename1.ui.CN.*;
import com.codename1.ui.Display;
import com.codename1.ui.Form;
import com.codename1.ui.Dialog;
import com.codename1.ui.Label;
import com.codename1.ui.plaf.UIManager;
import com.codename1.ui.util.Resources;
import com.codename1.io.Log;
import com.codename1.ui.Toolbar;
import java.io.IOException;
import com.codename1.ui.layouts.BoxLayout;
import com.codename1.io.NetworkEvent;
import com.codename1.io.Storage;
import com.codename1.io.Util;
import java.util.Timer;
import java.util.TimerTask;

/**
 * This file was generated by [Codename One](https://www.codenameone.com/) for the purpose
 * of building native mobile applications using Java.
 */
public class MyApplication {

    private Form current;
    private Resources theme;

    public void init(Object context) {
        // use two network threads instead of one
        updateNetworkThreadCount(2);

        theme = UIManager.initFirstTheme("/theme");

        // Enable Toolbar on all Forms by default
        Toolbar.setGlobalToolbar(true);

        // Pro only feature
        Log.bindCrashProtection(true);

        // Manage both network errors (connectivity issues) and server errors (codes different from 2xx)
        addNetworkAndServerErrorListener();
    }

    public void start() {
        if(current != null){
            current.show();
            return;
        }

        String url = "https://www.informatica-libera.net/video/AVO_Cariati_Pasqua_2020.mp4"; // 38 MB

        Form form = new Form("Test Download 38MB", BoxLayout.y());
        Label infoLabel = new Label("Starting download...");
        form.add(infoLabel);

        try {
            Util.downloadUrlSafely(url, "myHeavyVideo.mp4", (percentage) -> {
                // percentage callback
                infoLabel.setText("Downloaded: " + percentage + "%");
                infoLabel.repaint();
            }, (filename) -> {
                // file saved callback
                infoLabel.setText("Downloaded completed");
                int fileSizeMB = Storage.getInstance().entrySize(filename) / 1048576;
                form.add("Checking files size: " + fileSizeMB + " MB");
                form.revalidate();
            });
        } catch (IOException ex) {
            Log.p("Error in downloading: " + url);
            Log.e(ex);
            form.add(new SpanLabel("Error in downloading:\n" + url));
            form.revalidate();
        }

        form.show();


    }

    public void stop() {
        current = getCurrentForm();
        if(current instanceof Dialog) {
            ((Dialog)current).dispose();
            current = getCurrentForm();
        }
    }

    public void destroy() {
    }

    private void addNetworkAndServerErrorListener() {
        // The following way to manage network errors is discussed here:
        // https://stackoverflow.com/questions/61993127/distinguish-between-server-side-errors-and-connection-problems
        addNetworkErrorListener(err -> {
            // prevents the event from propagating
            err.consume();

            if (err.getError() != null) {
                // this is the case of a network error,
                // like: java.io.IOException: Unreachable
                Log.p("Error connectiong to: " + err.getConnectionRequest().getUrl(), Log.ERROR);
                // maybe there are connectivity issues, let's try again
                ToastBar.showInfoMessage("Reconnect...");
                Timer timer = new Timer();
                timer.schedule(new TimerTask() {
@Override
                    public void run() {
                        err.getConnectionRequest().retry();
                    }
                }, 2000);
            } else {
                // this is the case of a server error
                // logs the error
                String errorLog = "REST ERROR\nURL:" + err.getConnectionRequest().getUrl()
                        + "\nMethod: " + err.getConnectionRequest().getHttpMethod()
                        + "\nResponse code: " + err.getConnectionRequest().getResponseCode();
                if (err.getConnectionRequest().getRequestBody() != null) {
                    errorLog += "\nRequest body: " + err.getConnectionRequest().getRequestBody();
                }
                if (err.getConnectionRequest().getResponseData() != null) {
                    errorLog += "\nResponse message: " + new String(err.getConnectionRequest().getResponseData());
                }
                if (err.getConnectionRequest().getResponseErrorMessage() != null) {
                    errorLog += "\nResponse error message: " + err.getConnectionRequest().getResponseErrorMessage();
                }
                Log.p(errorLog, Log.ERROR);

                Log.sendLogAsync();
                ToastBar.showErrorMessage("Server Error", 10000);
            }
        });
    }

}
      Parameters

      • url

      • fileName: @param fileName must be a valid Storage file name or FileSystemStorage file path

      • percentageCallback: @param percentageCallback invoked (in EDT) during the download to notify the progress (from 0 to 100); it can be null if you are not interested in monitoring the progress

      • filesavedCallback: @param filesavedCallback invoked (in EDT) only when the download is finished; if null, no action is taken

      Throws
      • IOException
      Throws:
      IOException

    • getUUID

      public static String getUUID()

      Creates a new UUID, that is a 128-bit number used to identify information in computer systems. UUIDs aim to be unique for practical purposes.

      This implementation uses the system clock and some device info as seeds for random data, that are enough for practical usage. More specifically, two instances of Random, instantiated with different seeds, are used. The first seed corresponds to the timestamp in which the first object of the static class UUID is created, the second seed is a number (long type) that identifies the current installation of the app and is assumed to be as different as possible from other installations of the app. A unique identifier (long type) associated with the current app installation can be specified by the developer via the Preference "CustomDeviceId__$" (as in the following example) BEFORE the generation of the first UIID, or - if it is not specified - it is obtained from an internal Codename One implementation; in the worst case, if an identifier has not been specified by the developer and Codename One is unable to distinguish the current installation of the app from other installations, an internal algorithm will be used that will generate a number based on some hardware and software characteristics of the device: the number thus generated will be the same on identical models of the same device and with the same version of the operating system, but will vary between different models. Even in the worst case scenario, the probability that two app installations with identical device identifiers will generate the first UIID in the same timestamp is very low.

      As a tip, consider that any alphanumeric text string (corresponding for example to a username) can be converted into a long type number, considering this string as a number based on 36, provided it does not exceed 12 characters. This suggestion is applied in the following example.

      Code example:

      Form hi = new Form("Test UIID", BoxLayout.y());
Button button = new Button("Generate 10 UIID");
hi.add(button);
hi.show();
button.addActionListener(l -> {
    String myId = "myUsername"; // do not exceed 12 characters
    Preferences.set("CustomDeviceId__$", Long.parseLong(myId, 36));
    hi.add(new SpanLabel("10 Random UUID"));
    for (int i = 0; i < 10; i++) {
        hi.add(new SpanLabel(Util.getUIID()));
    }
    hi.revalidate();
});
      Returns
      Returns:
      a pseudo-random Universally Unique Identifier in its canonical textual representation

    • getUUID

      public static String getUUID(long time, long clockSeqAndNode)

      Creates a custom UUID, from the given two long values.

      Parameters

      • time: the upper 64 bits

      • clockSeqAndNode: the lower 64 bits

      Returns
      Returns:
      a Universally Unique Identifier in its canonical textual representation