FormFields
Date: 2016-12-04

net.htmlparser.jericho

## Class FormFields

- java.lang.Object
- - java.util.AbstractCollection<FormField>
  - - net.htmlparser.jericho.FormFields

- All Implemented Interfaces:
    java.lang.Iterable<FormField>, java.util.Collection<FormField>

      public final class FormFields
      extends java.util.AbstractCollection<FormField>

  Represents a collection of `FormField` objects.

  This class provides the main interface for the analysis and manipulation of form controls. A `FormFields` object is a collection of `FormField` objects, with each form field consisting of a group of form controls having the same name.

  The functionality provided by this class can be used to accomplish two main tasks:

  1. Modify the submission values of the constituent form controls for subsequent output in an `OutputDocument`.

     The methods available for this purpose are:
     `List<String> getValues(String fieldName)`
     `Map<String,String[]> getDataSet()`
     `void clearValues()`
     `void setDataSet(Map<String,String[]>)`
     `boolean setValue(String fieldName, String value)`
     `boolean addValue(String fieldName, String value)`

     Although the `FormField` and `FormControl` classes provide methods for directly modifying the submission values of individual form fields and controls, it is generally recommended to use the interface provided by this (the `FormFields`) class unless there is a specific requirement for the lower level functionality.

     The display characteristics of individual controls, such as whether the control is disabled, replaced with a simple value, or removed altogether, can only be set on the individual `FormControl` objects. See below for information about retrieving a specific `FormControl` object from the `FormFields` object.

  2. Convert data from a form data set (represented as a field data set) into a simple array format, suitable for storage in a tabular format such as a database table or `.CSV` file.

     The methods available for this purpose are:
     `String[] getColumnLabels()`
     `String[] getColumnValues(Map)`
     `String[] getColumnValues()`

     The `Util` class contains a method called `outputCSVLine(Writer,String[])` which writes the `String[]` output of these methods to the specified `Writer` in `.CSV` format.

     The implementation of these methods makes use of certain properties in the `FormField` class that describe the structure of the data in each field. These properties can be utilised directly in the event that a form data set is to be converted from its normal format into some other type of data structure.

  To access a specific `FormControl` from a `FormFields` object, use:

  - `formFields.` `get(fieldName)``.``getFormControl()` if the control is the only one with the specified name, or
  - `formFields.` `get(fieldName)``.``getFormControl(predefinedValue)` to retrieve the control having the speficied predefined value if it is part of a field containing multiple controls.

  The term field data set is used in this library to refer to a data structure consisting of a set of names (in lower case), each mapped to one or more values. Generally, this is represented by a data type of `java.util.Map<String,String[]>`, with the keys (names) being of type `String` and the values represented by an array containing one or more items of type `String`. A field data set can be used to represent the data in an HTML form data set.

  `FormFields` instances are obtained using the `FormFields(Collection formControls)` constructor or by calling the `Segment.getFormFields()` method.

  The case sensitivity of form field names is determined by the static `Config.CurrentCompatibilityMode``.``FormFieldNameCaseInsensitive` property.

  Examples:

  1. Write the data received from in the current `ServletRequest` to a `.CSV` file, and then display the form populated with this data:

             Source source=new Source(htmlTextOfOriginatingForm);
             FormFields formFields=source.getFormFields();

             File csvOutputFile=new File("FormData.csv");
             boolean outputHeadings=!csvOutputFile.exists();
             Writer writer=new FileWriter(csvOutputFile,true);
             if (outputHeadings) Util.outputCSVLine(writer,formFields.getColumnLabels());
             Util.outputCSVLine(writer,formFields.getColumnValues(servletRequest.getParameterMap()));
             writer.close();

             formFields.setDataSet(servletRequest.getParameterMap());
             OutputDocument outputDocument=new OutputDocument(source);
             outputDocument.replace(formFields);
             outputDocument.writeTo(servletResponse.getWriter());

     See also the sample program FormFieldCSVOutput.

  2. Replace the initial values of controls in the form named "MyForm" with new values:

             Source source=new Source(htmlText);
             Element myForm=null;
             List formElements=source.getAllElements(Tag.FORM);
             for (Iterator i=formElements.iterator(); i.hasNext();) {
               Element formElement=(Element)i.next();
               String formName=formElement.getAttributes().getValue("name");
               if ("MyForm".equals(formName)) {
                 myForm=form;
                 break;
               }
             }
             FormFields formFields=myForm.getFormFields();
             formFields.clearValues(); // clear any values that might be set in the source document
             formFields.addValue("Name","Humphrey Bear");
             formFields.addValue("MailingList","A");
             formFields.addValue("MailingList","B");
             formFields.addValue("FavouriteFare","honey");
             OutputDocument outputDocument=new OutputDocument(source);
             outputDocument.replace(formFields);
             String newHtmlText=outputDocument.toString();

     See also the sample program FormFieldSetValues.

  3. Change the display characteristics of individual controls:

             Source source=new Source(htmlText);
             FormFields formFields=source.getFormFields();
             // disable some controls:
             formFields.get("Password").getFormControl().setDisabled(true);
             FormField mailingListFormField=formFields.get("MailingList");
             mailingListFormField.setValue("C");
             mailingListFormField.getFormControl("C").setDisabled(true);
             mailingListFormField.getFormControl("D").setDisabled(true);
             // remove some controls:
             formFields.get("button1").getFormControl().setOutputStyle(FormControlOutputStyle.REMOVE);
             FormControl rhubarbFormControl=formFields.get("FavouriteFare").getFormControl("rhubarb");
             rhubarbFormControl.setOutputStyle(FormControlOutputStyle.REMOVE);
             // set some controls to display value:
             formFields.setValue("Address","The Lodge\nDeakin  ACT  2600\nAustralia");
             formFields.get("Address").getFormControl().setOutputStyle(FormControlOutputStyle.DISPLAY_VALUE);
             FormField favouriteSportsFormField=formFields.get("FavouriteSports");
             favouriteSportsFormField.setValue("BB");
             favouriteSportsFormField.addValue("AFL");
             favouriteSportsFormField.getFormControl().setOutputStyle(FormControlOutputStyle.DISPLAY_VALUE);
             OutputDocument outputDocument=new OutputDocument(source);
             outputDocument.replace(formFields); // adds all segments necessary to effect changes
             String newHtmlText=outputDocument.toString();

     See also the sample program FormControlDisplayCharacteristics.

  See Also:
    `FormField`, `FormControl`

- - ### Constructor Summary

    Constructors
    Constructor and Description
    `FormFields(java.util.Collection<FormControl> formControls)` Constructs a new `FormFields` object consisting of the specified form controls.

  - ### Method Summary

    Methods
    Modifier and Type | Method and Description
    --- | ---
    `boolean` | `addValue(java.lang.String fieldName, java.lang.String value)` Adds the specified value to the field submission values of the constituent form field with the specified name.
    `void` | `clearValues()` Clears the submission values of all the constituent form controls.
    `FormField` | `get(java.lang.String fieldName)` Returns the `FormField` with the specified name.
    `java.lang.String[]` | `getColumnLabels()` Returns a string array containing the column labels corresponding to the values from the `getColumnValues(Map)` method.
    `java.lang.String[]` | `getColumnValues()` Converts all the form submission values of the constituent form fields into a simple string array, suitable for storage in a tabular format such as a database table or `.CSV` file.
    `java.lang.String[]` | `getColumnValues(java.util.Map<java.lang.String,java.lang.String[]> dataSet)` Converts the data values in the specified field data set into a simple string array, suitable for storage in a tabular format such as a database table or `.CSV` file.
    `int` | `getCount()` Returns the number of `FormField` objects.
    `java.util.Map<java.lang.String,java.lang.String[]>` | `getDataSet()` Returns the entire field data set represented by the values of the constituent form fields.
    `java.lang.String` | `getDebugInfo()` Returns a string representation of this object useful for debugging purposes.
    `java.util.List` | `getFormControls()` Returns a list of all the constituent form controls from all the form fields in this collection.
    `java.util.List<java.lang.String>` | `getValues(java.lang.String fieldName)` Returns a list of the field submission values of all the specified constituent form fields with the specified name.
    `java.util.Iterator<FormField>` | `iterator()` Returns an iterator over the `FormField` objects in the collection.
    `void` | `merge(FormFields formFields)` Merges the specified `FormFields` into this `FormFields` collection.
    `void` | `setDataSet(java.util.Map<java.lang.String,java.lang.String[]> dataSet)` Sets the submission values of all the constituent form controls to match the data in the specified field data set.
    `boolean` | `setValue(java.lang.String fieldName, java.lang.String value)` Sets the field submission values of the constituent form field with the specified name to the single specified value.
    `int` | `size()` Returns the number of `FormField` objects.
    `java.lang.String` | `toString()` Returns a string representation of this object useful for debugging purposes.

    - ### Methods inherited from class java.util.AbstractCollection

      `add, addAll, clear, contains, containsAll, isEmpty, remove, removeAll, retainAll, toArray, toArray`

    - ### Methods inherited from class java.lang.Object

      `clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait`

    - ### Methods inherited from interface java.util.Collection

      `equals, hashCode`

- - ### Constructor Detail

    - #### FormFields

          public FormFields(java.util.Collection<FormControl> formControls)

      Constructs a new `FormFields` object consisting of the specified form controls.
      Parameters:
        `formControls` - a collection of `FormControl` objects.
      See Also:
        `Segment.getFormFields()`

  - ### Method Detail

    - #### getCount

          public int getCount()

      Returns the number of `FormField` objects.
      Returns:
        the number of `FormField` objects.

    - #### size

          public int size()

      Returns the number of `FormField` objects.

      This is equivalent to `getCount()`, and is necessary to for the implementation of the `java.util.Collection` interface.

      Specified by:
        `size` in interface `java.util.Collection<FormField>`
      Specified by:
        `size` in class `java.util.AbstractCollection<FormField>`
      Returns:
        the number of `FormField` objects.

    - #### get

          public FormField get(java.lang.String fieldName)

      Returns the `FormField` with the specified name.

      The case sensitivity of the `fieldName` argument is determined by the static `Config.CurrentCompatibilityMode``.``FormFieldNameCaseInsensitive` property.

      Parameters:
        `fieldName` - the name of the `FormField` to get.
      Returns:
        the `FormField` with the specified name, or `null` if no `FormField` with the specified name exists.

    - #### iterator

          public java.util.Iterator<FormField> iterator()

      Returns an iterator over the `FormField` objects in the collection.

      The order in which the form fields are iterated corresponds to the order of appearance of each form field's first `FormControl` in the source document.

      If this `FormFields` object has been merged with another, the ordering is no longer defined.

      Specified by:
        `iterator` in interface `java.lang.Iterable<FormField>`
      Specified by:
        `iterator` in interface `java.util.Collection<FormField>`
      Specified by:
        `iterator` in class `java.util.AbstractCollection<FormField>`
      Returns:
        an iterator over the `FormField` objects in the collection.

    - #### getValues

          public java.util.List<java.lang.String> getValues(java.lang.String fieldName)

      Returns a list of the field submission values of all the specified constituent form fields with the specified name.

      All objects in the returned list are of type `String`, with no `null` entries.

      This is equivalent to `get(fieldName)``.``getValues()`, assuming that a field with the specified name exists in this collection.

      Parameters:
        `fieldName` - the name of the form field.
      Returns:
        a list of the field submission values of all the specified constituent form field with the specified name, or `null` if no form field with this name exists.
      See Also:
        `FormField.getValues()`

    - #### getDataSet

          public java.util.Map<java.lang.String,java.lang.String[]> getDataSet()

      Returns the entire field data set represented by the values of the constituent form fields.

      The values in the map returned by this method are represented as a string array, giving the map a format consistent with the `javax.servlet.ServletRequest.getParameterMap()` method.

      Only the names of form fields with at least one value are included in the map, meaning every `String[]` is guaranteed to have at least one entry.

      Iterating over the map keys returns them in the order of appearance in the source document.

      Returns:
        the entire field data set represented by the values of the constituent form fields.
      See Also:
        `setDataSet(Map)`

    - #### clearValues

          public void clearValues()

      Clears the submission values of all the constituent form controls.
      See Also:
        `FormControl.clearValues()`

    - #### setDataSet

          public void setDataSet(java.util.Map<java.lang.String,java.lang.String[]> dataSet)

      Sets the submission values of all the constituent form controls to match the data in the specified field data set.

      The map keys must be `String` field names, with each map value an array of `String` objects containing the field's new values.

      The map returned by the `javax.servlet.ServletRequest.getParameterMap()` method has a suitable format for use with this method.

      All existing values are cleared before the values from the field data set are added.

      Any map entries with a `null` value are ignored.

      Parameters:
        `dataSet` - the field data set containing the new values of the constituent form fields.
      See Also:
        `getDataSet()`

    - #### setValue

          public boolean setValue(java.lang.String fieldName,
                         java.lang.String value)

      Sets the field submission values of the constituent form field with the specified name to the single specified value.

      This is equivalent to `get(fieldName)``.``setValue(value)`, assuming that a field with the specified name exists in this collection.

      The return value indicates whether the specified form field "accepted" the value. A return value of `false` implies an error condition as either no field with the specified name exists, or the specified value is not compatible with the specified field.

      Parameters:
        `fieldName` - the name of the form field.
        `value` - the new field submission value of the specified field, or `null` to clear the field of all submission values.
      Returns:
        `true` if a field of the specified name exists in this collection and it accepts the specified value, otherwise `false`.

    - #### addValue

          public boolean addValue(java.lang.String fieldName,
                         java.lang.String value)

      Adds the specified value to the field submission values of the constituent form field with the specified name.

      This is equivalent to `get(fieldName)``.``addValue(value)`, assuming that a field with the specified name exists in this collection.

      The return value indicates whether the specified form field "accepted" the value. A return value of `false` implies an error condition as either no field with the specified name exists, or the specified value is not compatible with the specified field.

      Parameters:
        `fieldName` - the name of the form field.
        `value` - the new field submission value to add to the specified field, must not be `null`.
      Returns:
        `true` if a field of the specified name exists in this collection and it accepts the specified value, otherwise `false`.

    - #### getColumnLabels

          public java.lang.String[] getColumnLabels()

      Returns a string array containing the column labels corresponding to the values from the `getColumnValues(Map)` method.

      Instead of using the name of each constituent form field to construct the labels, the name of the first form control from each form field is used. This allows the labels to be constructed using the names with the original case from the source document rather than unsing the all lower case names of the form fields.

      See the documentation of the `getColumnValues(Map)` method for more details.

      Returns:
        a string array containing the column labels corresponding to the values from the `getColumnValues(Map)` method.
      See Also:
        `Util.outputCSVLine(Writer,String[])`

    - #### getColumnValues

          public java.lang.String[] getColumnValues(java.util.Map<java.lang.String,java.lang.String[]> dataSet)

      Converts the data values in the specified field data set into a simple string array, suitable for storage in a tabular format such as a database table or `.CSV` file.

      The conversion is performed in a way that allows the multiple values of certain fields to be stored in separate columns, by analysing the possible form data sets that can be generated from the constituent form controls.

      The column labels and values are determined as follows:

      - For each form field in this collection (taken in iterator order):
        - If the form field has no predefined values, such as a single text control, then:
          - Add a single column:

            Label: | the name of the form field in original case
            Value: | the single value mapped to this field in the specified field data set.

            In the unlikely event that this field contains more than one value, all values are included in this one column and separated by the text defined in the static `Config.ColumnMultipleValueSeparator` property.
        - Otherwise, if the form field does have predefined values, but does not allow multiple values, then:
          - If the form field has only one predefined value, such as a single checkbox, then:
            - Add a single boolean column:

              Label: | the name of the form field in original case
              Value: | the currently configured string representation for true if a value mapped to this field in the specified field data set matches the predefined value, otherwise false

          - Otherwise, if the form field has more than one predefined value, such as a set of radio buttons, then:
            - Add a single column:

              Label: | the name of the form field in original case
              Value: | the single value mapped to this field in the specified field data set, which in the case of a set of radio buttons should be the predefined value of the checked radio button.

        - Otherwise, if the form field has predefined values and allows multiple values, such as a set of checkboxes, then:
          - For each predefined value in the form field:
            - Add a boolean column:

              Label: | "`FieldName.PredefinedValue`", where `FieldName` is the name of the form field in original case, and `PredefinedValue` is the predefined value.
              Value: | the currently configured string representation for true if a value mapped to this field in the specified field data set matches the predefined value, otherwise false

          - In addition, if the form field can also contain user values (`FormField.getUserValueCount()``>0`), then:
            - Add another column:

              Label: | the name of the form field in original case
              Value: | all values mapped to this field in the specified field data set that do not match any of the predefined values, separated by the text defined in the static `Config.ColumnMultipleValueSeparator` property.

      The sample program FormFieldCSVOutput demonstrates the use of this method and its output.

      Parameters:
        `dataSet` - a field data set containing the data to convert.
      Returns:
        the data values in the specified field data set in the form of a simple string array.
      See Also:
        `Util.outputCSVLine(Writer,String[])`, `getColumnLabels()`, `getColumnValues()`

    - #### getColumnValues

          public java.lang.String[] getColumnValues()

      Converts all the form submission values of the constituent form fields into a simple string array, suitable for storage in a tabular format such as a database table or `.CSV` file.

      This is equivalent to `getColumnValues``(``getDataSet()``)`.

      Returns:
        all the form submission values of the constituent form fields in the form of a simple string array.

    - #### getFormControls

          public java.util.List getFormControls()

      Returns a list of all the constituent form controls from all the form fields in this collection.
      Returns:
        a list of all the constituent form controls from all the form fields in this collection.

    - #### merge

          public void merge(FormFields formFields)

      Merges the specified `FormFields` into this `FormFields` collection. This is useful if a full collection of possible form fields is required from multiple source documents.

      If both collections contain a `FormField` with the same name, the resulting `FormField` has the following properties:

      - `getUserValueCount()` : the maximum user value count from both form fields
      - `allowsMultipleValues()` : `true` if either form field allows multiple values
      - `getPredefinedValues()` : the union of predefined values in both form fields
      - `getFormControls()` : the union of form controls from both form fields

      NOTE: Some underlying data structures may end up being shared between the two merged `FormFields` collections.

    - #### getDebugInfo

          public java.lang.String getDebugInfo()

      Returns a string representation of this object useful for debugging purposes.
      Returns:
        a string representation of this object useful for debugging purposes.

    - #### toString

          public java.lang.String toString()

      Returns a string representation of this object useful for debugging purposes.

      This is equivalent to `getDebugInfo()`.

      Overrides:
        `toString` in class `java.util.AbstractCollection<FormField>`
      Returns:
        a string representation of this object useful for debugging purposes.