Class Results

  • All Implemented Interfaces:
    java.io.Serializable, java.lang.Cloneable
    public class Results
extends java.lang.Object
implements java.io.Serializable, java.lang.Cloneable
    ImageScraper-Suite Class
    The ImageScraper Tool itself includes three 'Helper-Classes' that facilitate its operations. These three Helpers include: Request, Results and ImageInfo.

    Building a Request:
    Building an Image-Download Request instance really should be extremely easy, and there is an example of doing just that at the top of the Request class. Properly configuring the class to handle any / all possible errors or exceptions that might occur when downloading images from a web-server requires a little reading of the JavaDoc pages provided by these tools.

    The Request class includes several boolean's for supressing / skipping exception if they occur during the download loop / process iteration. If an exception is thrown and suppressed, it will simply be logged to the Results class.

    Once a Request Object has been built, simply pass that object-instance to the ImageScraper method download and a download-process will begin.

    Request's Lambda-Targets:
    If the Request object contained any Lambda-Target / Function-Pointers, then those Lambda-Methods will be passed instances of the 'Helper-Class' ImageInfo when they are invoked by the download-loop. These Function-Pointers provide just a few features that allow a programmer to do things like filter-out certain Image-URL's and also do things like decide where a downloaded Image is ultimately stored.

    Finally, when the download-loop has run to completely, it will return an instance of class Results

    Getting Results:
    After the ImageScraper.download(...) loop has run to completion, an instance of class Results will be returned tot he user, and it will simply contain several parallel-arrays that hold / store data about what transpired when trying to download each of the Image-URL's which were passed to the Request-Object.

    For instance the 'skipped' array will indicate which pictures didn't download. The 'fileNames' array will hold the name of the file of each image that was successfully downloaded. And the 'imageFormats' will identify which format was ultimately decided-upon when saving the image.

    Remember that each of these return-arrays are parallel to eachother, and (or course) will be identical in length. Furthermore, as per the definition of "Parallel-Arrays", the element residing at any index will always correspond to the same image in any one of the other arrays.
    After downloading all of the user's requested images, the class ImageScraper returns an instance of this class.

    When a download request has completed, this class will be instantiated and returned. Care has been taken to ensure this class does not freeze nor fail when a particular image fails to download. This level of control is customizable, so if the programmer would prefer download execution to halt immediately upon exception, there is are several settings for this in the class Request.

    The link below contains the output of invoking the toString method on a 'Results' instance after downloading all of the HTML <IMG SRC=...> tags that were scraped from the Web-Server news.yahoo.com.

    results.txt

    Initializations:
    Many of the values in the arrays for class 'Results' (this class) may contain null-values, or a '-1'. This happens if an exceptions is thrown while downloading or saving any one particular image, which prevents the process from running to completion.

    To view the exact initialization-value for elements of any of these array, simply click on the HiLited Source-Code link, and scroll down to the Package-Private Results class constructor.

    The 'skipped' Array:
    There is an easy way to check which URL's have failed or were skipped (due to user-request), and which URL's were successfully obtained. One of several arrays that are public in this class is the skipped boolean[]-array.

    Whenever a particular URL-index corresponds to a skipped-index that contains a FALSE boolean-value, it indicates that that particular URL ultimately was not properly saved or re-transmitted.
    See Also:
    ImageScraper, Serialized Form


    • Field Summary

       
      Serializable ID
      Modifier and Type Field
      static long serialVersionUID
       
      Parallel Result-Arrays:Original Source-Location of the Image
      Modifier and Type Field
      boolean[] b64EncodedImg
      URL[] urls
       
      Parallel Result-Arrays:Image-Retrieval Success or Failure
      Modifier and Type Field
      Exception[] exceptions
      boolean[] skipped
       
      Parallel Result-Arrays:Image-File Write Name & Location
      Modifier and Type Field
      String[] fileNames
      String[] saveDirectories
       
      Parallel Result-Arrays:Image Specs
      Modifier and Type Field
      int[] heights
      IF[] imageFormats
      long[] sizes
      int[] widths

    • Method Summary

       
      Methods: interface java.lang.Cloneable
      Modifier and Type Method
      Results clone()
       
      Methods: class java.lang.Object
      Modifier and Type Method
      boolean equals​(Object other)
      int hashCode()
      String toString()

      • Methods inherited from class java.lang.Object

        finalize, getClass, notify, notifyAll, wait, wait, wait

    • Field Detail

      • serialVersionUID

        🡇  ⇈  ⮫ 🗕  🗗  🗖 
        public static final long serialVersionUID
        This fulfils the SerialVersion UID requirement for all classes that implement Java's interface java.io.Serializable. Using the Serializable Implementation offered by java is very easy, and can make saving program state when debugging a lot easier. It can also be used in place of more complicated systems like "hibernate" to store data as well.
        See Also:
        Constant Field Values

      • urls

        🡅  🡇  ⇈  ⮫ 🗕  🗗  🗖 
        public final java.net.URL[] urls
        This will contain a complete list of the URL's that were retrieved (or generated- if partially-resolved 'relative' URL's were provided) from the Request-instances static-builder. Every image downloaded (or attempted for download) will have its URL saved here, in this array.

        Null's in the urls Array
        An array-element of the urls-array will contain null under the following two circumstances:

        • No image-URL was provided, becasue the picture was a Base-64 Encoded Image, and instead was a String that had been retrieved from a TagNode's SRC-Attribute.

        • The user provided a String to the Request Class builder, but that String caused a MalformedURLException, and no URL-instance was ever built. (Note that in this scenario, the exceptions-array would be storing the URL-Exception that was thrown).



        Parallel Arrays: The index of this array will be parallel to the input-source Iterable<URL> retrieval order. All array-indices in this array contain elements that are parallel to the corresponding elements in the other 9 array-fields of this Results Class.

      • b64EncodedImg

        🡅  🡇  ⇈  ⮫ 🗕  🗗  🗖 
        public final boolean[] b64EncodedImg
        When constructing an ImageScraper's Request object, one of the options for building the instance is to pass a list of HTML TagNode instances containing HTML '<IMG SRC=...>' tags.

        HTML TagNode elements will sometimes / occasionally have a variant of an image source known as the Base-64 Encoded Image. These are images where the actual pictures fully stored & encoded inside the SRC-Attribute of the HTML TagNode 's SRC-Attribute.

        Base-64 Images are just pictures that have been converted into actual character data, in the form of a simple String, and saved into the <IMG> tag's SRC-URL - instead of an actual HTTP URL being saved there. Note that this practice is generally used for much smaller pictures, thumbnails or logo signs (images that wouldn't use up a lot of data).

        A full explanation of HTML's Base-64 Image-Encoding is beyone the scope of this Java-Doc Comment.

        If any image was "converted" from a B-64 Image-Encoding (rather than downloaded from a URL), then the boolean for the image's index will be TRUE rather than FALSE. The default value for all elements of this array is FALSE.

        Parallel Arrays: The index of this array will be parallel to the input-source Iterable<URL> retrieval order. All array-indices in this array contain elements that are parallel to the corresponding elements in the other 9 array-fields of this Results Class.

      • skipped

        🡅  🡇  ⇈  ⮫ 🗕  🗗  🗖 
        public final boolean[] skipped
        An images Results-data in this particular paralell-array will be TRUE under any of the following circumstances:

        • If the user provided a Request.skipURL-Predicate, and that predicate rejected the image (telling the downloader not to download the picture).

        • If the user provided a Request.keeperPredicate, and that predicate, after image-downloade complettion, rejected the image (telling the downloader not save the picture to disk the picture).

        • If there were any exceptions thrown while downloading the image that forced the downloader-logic to abandon the image (and either throw the exception, or skip-and-move-on to the next image).

        • If the original Iterable that was provided to the Request-instance had entries that had caused exceptions to be thrown while building the Request-instance.

        Under any / all other circumstances, if an image was successfully downloaded and written to disk, then the corresponding element in this array will contain FALSE!

        Parallel Arrays: The index of this array will be parallel to the input-source Iterable<URL> retrieval order. All array-indices in this array contain elements that are parallel to the corresponding elements in the other 9 array-fields of this Results Class.

      • fileNames

        🡅  🡇  ⇈  ⮫ 🗕  🗗  🗖 
        public final java.lang.String[] fileNames
        The names of the files that were retrieved and/or stored will be in this array. If this image were skipped or an exception occurred, the array position for that URL would contain 'null'.

        It is important to note that if an element of this array contains a valid, non-null, file-name - it does not guarantee that the image was properly saved. The value stored in the corresponding (parallel) skipped-array index is the only way to ascertain whether an image was ultimately written to disk (or transmitted to a User-Provided Request.imageReceiver ).

        Parallel Arrays: The index of this array will be parallel to the input-source Iterable<URL> retrieval order. All array-indices in this array contain elements that are parallel to the corresponding elements in the other 9 array-fields of this Results Class.

      • saveDirectories

        🡅  🡇  ⇈  ⮫ 🗕  🗗  🗖 
        public final java.lang.String[] saveDirectories
        The location of the file-name saved directory, if an image did not successfully save to the File-System, or if an imageReceiver were used, then the array-location would contain 'null'.

        Parallel Arrays: The index of this array will be parallel to the input-source Iterable<URL> retrieval order. All array-indices in this array contain elements that are parallel to the corresponding elements in the other 9 array-fields of this Results Class.

      • imageFormats

        🡅  🡇  ⇈  ⮫ 🗕  🗗  🗖 
        public final IF[] imageFormats
        The image type of the files that were retrieved will be stored in this array.

        Image-Download Skipped:
        If the image-downloader threw an exception while attempting to download a particular image, then the sizes-array at that image's index would contain null (and the skipped-array would contain TRUE).

        If the user-provided skipURL-Predicate asked that a URL be skipped, then the element at that array-index would also contain null.

        Image-Download Succeeded:
        If a particular Image-URL was successfully downloaded, but if the User-Provided keeperPredicate has asked that the downloader not save the image to disk, then the value in this array would contain that image's image-format anyway!. This would be despite the fact that the image wasn't actually written to disk.

        If, after downloading, an image failed to write to disk due to an exception, then the value in this array would, also / again, contain that image's image-format - even though the image itself hadn't properly saved. (The skipped-array would still have a TRUE value stored in it).

        In Summary: When an image is skipped due to an exception, or some other issue that occurred during the downloader-loop, partially-acquired information about the picture will still be written to the class Results-arrays - whether or not the image has been saved to the file-system.

        Parallel Arrays: The index of this array will be parallel to the input-source Iterable<URL> retrieval order. All array-indices in this array contain elements that are parallel to the corresponding elements in the other 9 array-fields of this Results Class.

      • exceptions

        🡅  🡇  ⇈  ⮫ 🗕  🗗  🗖 
        public final java.lang.Exception[] exceptions
        If any stage of the image download, conversion or disk-write fails, then this array will store a record the exception that was thrown.

        If the download succeeded, then the 'exceptions'-array element at that index would contain 'null.' Any exceptions-array index that contains a non-null Exception will be an index for which the skipped-array contains a TRUE-value stored at the same location.

        Parallel Arrays: The index of this array will be parallel to the input-source Iterable<URL> retrieval order. All array-indices in this array contain elements that are parallel to the corresponding elements in the other 9 array-fields of this Results Class.

      • sizes

        🡅  🡇  ⇈  ⮫ 🗕  🗗  🗖 
        public final long[] sizes
        This will contain a list of long-integers, each of which will have the file-size of the downloaded image.

        Image-Download Skipped:
        If the image-downloader threw an exception while attempting to download a particular image, then the sizes-array at that image's index would contain -1 (and the skipped-array would contain TRUE).

        If the user-provided skipURL-Predicate asked that a URL be skipped, then the element at that array-index would also contain -1.

        Image-Download Succeeded:
        If a particular Image-URL was successfully downloaded, but if the User-Provided keeperPredicate has asked that the downloader not save the image to disk, then the value in this array would contain that image's size anyway!. This would be despite the fact that the image wasn't actually written to disk.

        If, after downloading, an image failed to write to disk due to an exception, then the value in this array would, also / again, contain that image's size - even though the image itself hadn't properly saved. (The skipped-array would still have a TRUE value stored in it).

        In Summary: When an image is skipped due to an exception, or some other issue that occurred during the downloader-loop, partially-acquired information about the picture will still be written to the class Results-arrays - whether or not the image has been saved to the file-system.

        Parallel Arrays: The index of this array will be parallel to the input-source Iterable<URL> retrieval order. All array-indices in this array contain elements that are parallel to the corresponding elements in the other 9 array-fields of this Results Class.

      • widths

        🡅  🡇  ⇈  ⮫ 🗕  🗗  🗖 
        public final int[] widths
        This will contain a list of integers, each of which shall have the image-widths of the downloaded images.

        Image-Download Skipped:
        If the image-downloader threw an exception while attempting to download a particular image, then the sizes-array at that image's index would contain -1 (and the skipped-array would contain TRUE).

        If the user-provided skipURL-Predicate asked that a URL be skipped, then the element at that array-index would also contain -1.

        Image-Download Succeeded:
        If a particular Image-URL was successfully downloaded, but if the User-Provided keeperPredicate has asked that the downloader not save the image to disk, then the value in this array would contain that image's width anyway!. This would be despite the fact that the image wasn't actually written to disk.

        If, after downloading, an image failed to write to disk due to an exception, then the value in this array would, also / again, contain that image's width - even though the image itself hadn't properly saved. (The skipped-array would still have a TRUE value stored in it).

        In Summary: When an image is skipped due to an exception, or some other issue that occurred during the downloader-loop, partially-acquired information about the picture will still be written to the class Results-arrays - whether or not the image has been saved to the file-system.

        Parallel Arrays: The index of this array will be parallel to the input-source Iterable<URL> retrieval order. All array-indices in this array contain elements that are parallel to the corresponding elements in the other 9 array-fields of this Results Class.

      • heights

        🡅  🡇  ⇈  ⮫ 🗕  🗗  🗖 
        public final int[] heights
        This shall contain a list of integers, each of which shall have the image-heights of the downloaded images.

        Image-Download Skipped:
        If the image-downloader threw an exception while attempting to download a particular image, then the sizes-array at that image's index would contain -1 (and the skipped-array would contain TRUE).

        If the user-provided skipURL-Predicate asked that a URL be skipped, then the element at that array-index would also contain -1.

        Image-Download Succeeded:
        If a particular Image-URL was successfully downloaded, but if the User-Provided keeperPredicate has asked that the downloader not save the image to disk, then the value in this array would contain that image's height anyway!. This would be despite the fact that the image wasn't actually written to disk.

        If, after downloading, an image failed to write to disk due to an exception, then the value in this array would, also / again, contain that image's height - even though the image itself hadn't properly saved. (The skipped-array would still have a TRUE value stored in it).

        In Summary: When an image is skipped due to an exception, or some other issue that occurred during the downloader-loop, partially-acquired information about the picture will still be written to the class Results-arrays - whether or not the image has been saved to the file-system.

        Parallel Arrays: The index of this array will be parallel to the input-source Iterable<URL> retrieval order. All array-indices in this array contain elements that are parallel to the corresponding elements in the other 9 array-fields of this Results Class.

    • Method Detail

      • clone

        🡅  🡇  ⇈  ⮫ 🗕  🗗  🗖 
        public Results clone()
        Generates a Deep Copy of 'this' instance. This means all internal arrays are also cloned / copied
        Overrides:
        clone in class java.lang.Object
        Returns:
        A duplicate instance of this class, with all arrays having been copied.
        Code:
        Exact Method Body:
         return new Results(this);

      • equals

        🡅  🡇  ⇈  ⮫     External-Java:   ⮫ 🗕  🗗  🗖 
        public boolean equals​(java.lang.Object other)
        Checks whether 'this' instance is equal to another instance of class Results. This method performs a Deep Equals comparison using the equals(...) method suite found in class' java.util.Arrays.
        Overrides:
        equals in class java.lang.Object
        Parameters:
        other - This may be any Java Object, but only an instance class 'Results' has any chance of being marked as equal to this instance.
        Returns:
        TRUE if and only if 'o' has a type that's assignable to Results - and if each of the internal arrays in this instance are equal to the arrays in parameter 'o'.
        Code:
        Exact Method Body:
         return ResultsEquals.equals(this, other);

      • toString

        🡅  🡇  ⇈  ⮫     External-Java:   ⮫ 🗕  🗗  🗖 
        public java.lang.String toString()
        Returns a java.lang.String representation of 'this' instance
        Overrides:
        toString in class java.lang.Object
        Returns:
        A Java String containing the data inside this class.
        Code:
        Exact Method Body:
         return ResultsToString.run(this);

      • hashCode

        🡅  ⇈  ⮫ 🗕  🗗  🗖 
        public int hashCode()
        Java's hash-code requirement. The code is computed by summing the first 10 sizes array elements.
        Overrides:
        hashCode in class java.lang.Object
        Returns:
        A hash-code that may be used when storing this node in a java sorted-collection.
        Code:
        Exact Method Body:
         int sum = 0;

 for (int i=0; (i < 10) && (i < sizes.length); i++) sum += sizes[i];

 return sum;