Module javafx.base
Package javafx.beans.binding

## Class StringExpression

- java.lang.Object
- - javafx.beans.binding.StringExpression

- All Implemented Interfaces:
    `Observable`, `ObservableObjectValue<String>`, `ObservableStringValue`, `ObservableValue<String>`
  Direct Known Subclasses:
    `ReadOnlyStringProperty`, `StringBinding`

      public abstract class StringExpression
      extends Object
      implements ObservableStringValue

  `StringExpression` is an `ObservableStringValue` plus additional convenience methods to generate bindings in a fluent style.

  A concrete sub-class of `StringExpression` has to implement the method `ObservableObjectValue.get()`, which provides the actual value of this expression.

  Note: all implementation of `BooleanBinding` returned by the comparisons in this class consider a `String` that is `null` equal to an empty `String`.

  Since:
    JavaFX 2.0

- - ### Constructor Summary

    Constructors
    Constructor | Description
    --- | ---
    `StringExpression()` |

  - ### Method Summary

    Modifier and Type | Method | Description
    --- | --- | ---
    `StringExpression` | `concat​(Object other)` | Returns a `StringExpression` that holds the value of this `StringExpression` concatenated with another `Object`.
    `String` | `getValue()` | Returns the current value of this `ObservableValue`
    `String` | `getValueSafe()` | Returns usually the value of this `StringExpression`.
    `BooleanBinding` | `greaterThan​(String other)` | Creates a new `BooleanBinding` that holds `true` if this `StringExpression` is greater than a constant value.
    `BooleanBinding` | `greaterThan​(ObservableStringValue other)` | Creates a new `BooleanBinding` that holds `true` if this `StringExpression` is greater than another `ObservableStringValue`.
    `BooleanBinding` | `greaterThanOrEqualTo​(String other)` | Creates a new `BooleanBinding` that holds `true` if this `StringExpression` is greater than or equal to a constant value.
    `BooleanBinding` | `greaterThanOrEqualTo​(ObservableStringValue other)` | Creates a new `BooleanBinding` that holds `true` if this `StringExpression` is greater than or equal to another `ObservableStringValue`.
    `BooleanBinding` | `isEmpty()` | Creates a new `BooleanBinding` that holds `true` if this `StringExpression` is empty.
    `BooleanBinding` | `isEqualTo​(String other)` | Creates a new `BooleanBinding` that holds `true` if this `StringExpression` is equal to a constant value.
    `BooleanBinding` | `isEqualTo​(ObservableStringValue other)` | Creates a new `BooleanBinding` that holds `true` if this and another `ObservableStringValue` are equal.
    `BooleanBinding` | `isEqualToIgnoreCase​(String other)` | Creates a new `BooleanBinding` that holds `true` if this `StringExpression` is equal to a constant value ignoring case.
    `BooleanBinding` | `isEqualToIgnoreCase​(ObservableStringValue other)` | Creates a new `BooleanBinding` that holds `true` if this and another `ObservableStringValue` are equal ignoring case.
    `BooleanBinding` | `isNotEmpty()` | Creates a new `BooleanBinding` that holds `true` if this `StringExpression` is not empty.
    `BooleanBinding` | `isNotEqualTo​(String other)` | Creates a new `BooleanBinding` that holds `true` if this `StringExpression` is not equal to a constant value.
    `BooleanBinding` | `isNotEqualTo​(ObservableStringValue other)` | Creates a new `BooleanBinding` that holds `true` if this and another `ObservableStringValue` are not equal.
    `BooleanBinding` | `isNotEqualToIgnoreCase​(String other)` | Creates a new `BooleanBinding` that holds `true` if this `StringExpression` is not equal to a constant value ignoring case.
    `BooleanBinding` | `isNotEqualToIgnoreCase​(ObservableStringValue other)` | Creates a new `BooleanBinding` that holds `true` if this and another `ObservableStringValue` are not equal ignoring case.
    `BooleanBinding` | `isNotNull()` | Creates a new `BooleanBinding` that holds `true` if this `StringExpression` is not `null`.
    `BooleanBinding` | `isNull()` | Creates a new `BooleanBinding` that holds `true` if this `StringExpression` is `null`.
    `IntegerBinding` | `length()` | Creates a new `IntegerBinding` that holds the length of this `StringExpression`.
    `BooleanBinding` | `lessThan​(String other)` | Creates a new `BooleanBinding` that holds `true` if this `StringExpression` is less than a constant value.
    `BooleanBinding` | `lessThan​(ObservableStringValue other)` | Creates a new `BooleanBinding` that holds `true` if this `StringExpression` is less than another `ObservableStringValue`.
    `BooleanBinding` | `lessThanOrEqualTo​(String other)` | Creates a new `BooleanBinding` that holds `true` if this `StringExpression` is less than or equal to a constant value.
    `BooleanBinding` | `lessThanOrEqualTo​(ObservableStringValue other)` | Creates a new `BooleanBinding` that holds `true` if this `StringExpression` is less than or equal to another `ObservableStringValue`.
    `static StringExpression` | `stringExpression​(ObservableValue<?> value)` | Returns a `StringExpression` that wraps a `ObservableValue`.

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

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

    - ### Methods inherited from interface javafx.beans.Observable

      `addListener, removeListener`

    - ### Methods inherited from interface javafx.beans.value.ObservableObjectValue

      `get`

    - ### Methods inherited from interface javafx.beans.value.ObservableValue

      `addListener, removeListener`

- - ### Constructor Detail

    - #### StringExpression

          public StringExpression()

  - ### Method Detail

    - #### getValue

          public String getValue()

      Description copied from interface: `ObservableValue`
      Returns the current value of this `ObservableValue`
      Specified by:
        `getValue` in interface `ObservableValue<String>`
      Returns:
        The current value

    - #### getValueSafe

          public final String getValueSafe()

      Returns usually the value of this `StringExpression`. Only if the value is `null` an empty `String` is returned instead.
      Returns:
        the value of this `StringExpression` or the empty `String`

    - #### stringExpression

          public static StringExpression stringExpression​(ObservableValue<?> value)

      Returns a `StringExpression` that wraps a `ObservableValue`. If the `ObservableValue` is already a `StringExpression`, it will be returned. Otherwise a new `StringBinding` is created that holds the value of the `ObservableValue` converted to a `String`.
      Parameters:
        `value` - The source `ObservableValue`
      Returns:
        A `StringExpression` that wraps the `ObservableValue` if necessary
      Throws:
        `NullPointerException` - if `value` is `null`

    - #### concat

          public StringExpression concat​(Object other)

      Returns a `StringExpression` that holds the value of this `StringExpression` concatenated with another `Object`.

      If the value of this `StringExpression` changes, the value of the resulting `StringExpression` is updated automatically. Also if the other `Object` is an implementation of `ObservableValue`, changes in the other `Object` are reflected automatically in the resulting `StringExpression`.

      Parameters:
        `other` - the other `Object`
      Returns:
        the new `StringExpression`

    - #### isEqualTo

          public BooleanBinding isEqualTo​(ObservableStringValue other)

      Creates a new `BooleanBinding` that holds `true` if this and another `ObservableStringValue` are equal.

      Note: In this comparison a `String` that is `null` is considered equal to an empty `String`.

      Parameters:
        `other` - the constant value
      Returns:
        the new `BooleanBinding`

    - #### isEqualTo

          public BooleanBinding isEqualTo​(String other)

      Creates a new `BooleanBinding` that holds `true` if this `StringExpression` is equal to a constant value.

      Note: In this comparison a `String` that is `null` is considered equal to an empty `String`.

      Parameters:
        `other` - the constant value
      Returns:
        the new `BooleanBinding`

    - #### isNotEqualTo

          public BooleanBinding isNotEqualTo​(ObservableStringValue other)

      Creates a new `BooleanBinding` that holds `true` if this and another `ObservableStringValue` are not equal.

      Note: In this comparison a `String` that is `null` is considered equal to an empty `String`.

      Parameters:
        `other` - the constant value
      Returns:
        the new `BooleanBinding`

    - #### isNotEqualTo

          public BooleanBinding isNotEqualTo​(String other)

      Creates a new `BooleanBinding` that holds `true` if this `StringExpression` is not equal to a constant value.

      Note: In this comparison a `String` that is `null` is considered equal to an empty `String`.

      Parameters:
        `other` - the constant value
      Returns:
        the new `BooleanBinding`

    - #### isEqualToIgnoreCase

          public BooleanBinding isEqualToIgnoreCase​(ObservableStringValue other)

      Creates a new `BooleanBinding` that holds `true` if this and another `ObservableStringValue` are equal ignoring case.

      Note: In this comparison a `String` that is `null` is considered equal to an empty `String`.

      Parameters:
        `other` - the second `ObservableStringValue`
      Returns:
        the new `BooleanBinding`

    - #### isEqualToIgnoreCase

          public BooleanBinding isEqualToIgnoreCase​(String other)

      Creates a new `BooleanBinding` that holds `true` if this `StringExpression` is equal to a constant value ignoring case.

      Note: In this comparison a `String` that is `null` is considered equal to an empty `String`.

      Parameters:
        `other` - the constant value
      Returns:
        the new `BooleanBinding`

    - #### isNotEqualToIgnoreCase

          public BooleanBinding isNotEqualToIgnoreCase​(ObservableStringValue other)

      Creates a new `BooleanBinding` that holds `true` if this and another `ObservableStringValue` are not equal ignoring case.

      Note: In this comparison a `String` that is `null` is considered equal to an empty `String`.

      Parameters:
        `other` - the second `ObservableStringValue`
      Returns:
        the new `BooleanBinding`

    - #### isNotEqualToIgnoreCase

          public BooleanBinding isNotEqualToIgnoreCase​(String other)

      Creates a new `BooleanBinding` that holds `true` if this `StringExpression` is not equal to a constant value ignoring case.

      Note: In this comparison a `String` that is `null` is considered equal to an empty `String`.

      Parameters:
        `other` - the constant value
      Returns:
        the new `BooleanBinding`

    - #### greaterThan

          public BooleanBinding greaterThan​(ObservableStringValue other)

      Creates a new `BooleanBinding` that holds `true` if this `StringExpression` is greater than another `ObservableStringValue`.

      Note: In this comparison a `String` that is `null` is considered equal to an empty `String`.

      Parameters:
        `other` - the second `ObservableStringValue`
      Returns:
        the new `BooleanBinding`

    - #### greaterThan

          public BooleanBinding greaterThan​(String other)

      Creates a new `BooleanBinding` that holds `true` if this `StringExpression` is greater than a constant value.

      Note: In this comparison a `String` that is `null` is considered equal to an empty `String`.

      Parameters:
        `other` - the constant value
      Returns:
        the new `BooleanBinding`

    - #### lessThan

          public BooleanBinding lessThan​(ObservableStringValue other)

      Creates a new `BooleanBinding` that holds `true` if this `StringExpression` is less than another `ObservableStringValue`.

      Note: In this comparison a `String` that is `null` is considered equal to an empty `String`.

      Parameters:
        `other` - the second `ObservableStringValue`
      Returns:
        the new `BooleanBinding`

    - #### lessThan

          public BooleanBinding lessThan​(String other)

      Creates a new `BooleanBinding` that holds `true` if this `StringExpression` is less than a constant value.

      Note: In this comparison a `String` that is `null` is considered equal to an empty `String`.

      Parameters:
        `other` - the constant value
      Returns:
        the new `BooleanBinding`

    - #### greaterThanOrEqualTo

          public BooleanBinding greaterThanOrEqualTo​(ObservableStringValue other)

      Creates a new `BooleanBinding` that holds `true` if this `StringExpression` is greater than or equal to another `ObservableStringValue`.

      Note: In this comparison a `String` that is `null` is considered equal to an empty `String`.

      Parameters:
        `other` - the second `ObservableStringValue`
      Returns:
        the new `BooleanBinding`

    - #### greaterThanOrEqualTo

          public BooleanBinding greaterThanOrEqualTo​(String other)

      Creates a new `BooleanBinding` that holds `true` if this `StringExpression` is greater than or equal to a constant value.

      Note: In this comparison a `String` that is `null` is considered equal to an empty `String`.

      Parameters:
        `other` - the constant value
      Returns:
        the new `BooleanBinding`

    - #### lessThanOrEqualTo

          public BooleanBinding lessThanOrEqualTo​(ObservableStringValue other)

      Creates a new `BooleanBinding` that holds `true` if this `StringExpression` is less than or equal to another `ObservableStringValue`.

      Note: In this comparison a `String` that is `null` is considered equal to an empty `String`.

      Parameters:
        `other` - the second `ObservableStringValue`
      Returns:
        the new `BooleanBinding`

    - #### lessThanOrEqualTo

          public BooleanBinding lessThanOrEqualTo​(String other)

      Creates a new `BooleanBinding` that holds `true` if this `StringExpression` is less than or equal to a constant value.

      Note: In this comparison a `String` that is `null` is considered equal to an empty `String`.

      Parameters:
        `other` - the constant value
      Returns:
        the new `BooleanBinding`

    - #### isNull

          public BooleanBinding isNull()

      Creates a new `BooleanBinding` that holds `true` if this `StringExpression` is `null`.
      Returns:
        the new `BooleanBinding`

    - #### isNotNull

          public BooleanBinding isNotNull()

      Creates a new `BooleanBinding` that holds `true` if this `StringExpression` is not `null`.
      Returns:
        the new `BooleanBinding`

    - #### length

          public IntegerBinding length()

      Creates a new `IntegerBinding` that holds the length of this `StringExpression`.

      Note: If the value of this `StringExpression` is `null`, the length is considered to be `0`.

      Returns:
        the new `IntegerBinding`
      Since:
        JavaFX 8.0

    - #### isEmpty

          public BooleanBinding isEmpty()

      Creates a new `BooleanBinding` that holds `true` if this `StringExpression` is empty.

      Note: If the value of this `StringExpression` is `null`, it is considered to be empty.

      Returns:
        the new `BooleanBinding`
      Since:
        JavaFX 8.0

    - #### isNotEmpty

          public BooleanBinding isNotEmpty()

      Creates a new `BooleanBinding` that holds `true` if this `StringExpression` is not empty.

      Note: If the value of this `StringExpression` is `null`, it is considered to be empty.

      Returns:
        the new `BooleanBinding`
      Since:
        JavaFX 8.0