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package javafx.beans.binding;

import javafx.beans.value.ObservableLongValue;
import javafx.collections.FXCollections;
import javafx.collections.ObservableList;
import javafx.beans.value.ObservableValue;

LongExpression is an ObservableLongValue plus additional convenience methods to generate bindings in a fluent style.

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

Since:JavaFX 2.0
/** * {@code LongExpression} is an {@link javafx.beans.value.ObservableLongValue} * plus additional convenience methods to generate bindings in a fluent style. * <p> * A concrete sub-class of {@code LongExpression} has to implement the method * {@link javafx.beans.value.ObservableLongValue#get()}, which provides the * actual value of this expression. * @since JavaFX 2.0 */
public abstract class LongExpression extends NumberExpressionBase implements ObservableLongValue { @Override public int intValue() { return (int) get(); } @Override public long longValue() { return get(); } @Override public float floatValue() { return (float) get(); } @Override public double doubleValue() { return (double) get(); } @Override public Long getValue() { return get(); }
Returns a LongExpression that wraps a ObservableLongValue. If the ObservableLongValue is already a LongExpression, it will be returned. Otherwise a new LongBinding is created that is bound to the ObservableLongValue.
Params:
  • value – The source ObservableLongValue
Throws:
Returns:A LongExpression that wraps the ObservableLongValue if necessary
/** * Returns a {@code LongExpression} that wraps a * {@link javafx.beans.value.ObservableLongValue}. If the * {@code ObservableLongValue} is already a {@code LongExpression}, it will * be returned. Otherwise a new {@link javafx.beans.binding.LongBinding} is * created that is bound to the {@code ObservableLongValue}. * * @param value * The source {@code ObservableLongValue} * @return A {@code LongExpression} that wraps the * {@code ObservableLongValue} if necessary * @throws NullPointerException * if {@code value} is {@code null} */
public static LongExpression longExpression(final ObservableLongValue value) { if (value == null) { throw new NullPointerException("Value must be specified."); } return (value instanceof LongExpression) ? (LongExpression) value : new LongBinding() { { super.bind(value); } @Override public void dispose() { super.unbind(value); } @Override protected long computeValue() { return value.get(); } @Override public ObservableList<ObservableLongValue> getDependencies() { return FXCollections.singletonObservableList(value); } }; }
Returns a LongExpression that wraps an ObservableValue. If the ObservableValue is already a LongExpression, it will be returned. Otherwise a new LongBinding is created that is bound to the ObservableValue.

Note: this method can be used to convert an ObjectExpression or ObjectProperty of specific number type to LongExpression, which is essentially an ObservableValue<Number>. See sample below.

  LongProperty longProperty = new SimpleLongProperty(1L);
  ObjectProperty<Long> objectProperty = new SimpleObjectProperty<>(2L);
  BooleanBinding binding = longProperty.greaterThan(LongExpression.longExpression(objectProperty));
Note: null values will be interpreted as 0L
Params:
  • value – The source ObservableValue
Type parameters:
  • <T> – The type of Number to be wrapped
Throws:
Returns:A LongExpression that wraps the ObservableValue if necessary
Since:JavaFX 8.0
/** * Returns a {@code LongExpression} that wraps an * {@link javafx.beans.value.ObservableValue}. If the * {@code ObservableValue} is already a {@code LongExpression}, it * will be returned. Otherwise a new * {@link javafx.beans.binding.LongBinding} is created that is bound to * the {@code ObservableValue}. * * <p> * Note: this method can be used to convert an {@link ObjectExpression} or * {@link javafx.beans.property.ObjectProperty} of specific number type to LongExpression, which * is essentially an {@code ObservableValue<Number>}. See sample below. * * <blockquote><pre> * LongProperty longProperty = new SimpleLongProperty(1L); * ObjectProperty&lt;Long&gt; objectProperty = new SimpleObjectProperty&lt;&gt;(2L); * BooleanBinding binding = longProperty.greaterThan(LongExpression.longExpression(objectProperty)); * </pre></blockquote> * * Note: null values will be interpreted as 0L * * @param <T> The type of Number to be wrapped * @param value * The source {@code ObservableValue} * @return A {@code LongExpression} that wraps the * {@code ObservableValue} if necessary * @throws NullPointerException * if {@code value} is {@code null} * @since JavaFX 8.0 */
public static <T extends Number> LongExpression longExpression(final ObservableValue<T> value) { if (value == null) { throw new NullPointerException("Value must be specified."); } return (value instanceof LongExpression) ? (LongExpression) value : new LongBinding() { { super.bind(value); } @Override public void dispose() { super.unbind(value); } @Override protected long computeValue() { final T val = value.getValue(); return val == null ? 0L : val.longValue(); } @Override public ObservableList<ObservableValue<T>> getDependencies() { return FXCollections.singletonObservableList(value); } }; } @Override public LongBinding negate() { return (LongBinding) Bindings.negate(this); } @Override public DoubleBinding add(final double other) { return Bindings.add(this, other); } @Override public FloatBinding add(final float other) { return (FloatBinding) Bindings.add(this, other); } @Override public LongBinding add(final long other) { return (LongBinding) Bindings.add(this, other); } @Override public LongBinding add(final int other) { return (LongBinding) Bindings.add(this, other); } @Override public DoubleBinding subtract(final double other) { return Bindings.subtract(this, other); } @Override public FloatBinding subtract(final float other) { return (FloatBinding) Bindings.subtract(this, other); } @Override public LongBinding subtract(final long other) { return (LongBinding) Bindings.subtract(this, other); } @Override public LongBinding subtract(final int other) { return (LongBinding) Bindings.subtract(this, other); } @Override public DoubleBinding multiply(final double other) { return Bindings.multiply(this, other); } @Override public FloatBinding multiply(final float other) { return (FloatBinding) Bindings.multiply(this, other); } @Override public LongBinding multiply(final long other) { return (LongBinding) Bindings.multiply(this, other); } @Override public LongBinding multiply(final int other) { return (LongBinding) Bindings.multiply(this, other); } @Override public DoubleBinding divide(final double other) { return Bindings.divide(this, other); } @Override public FloatBinding divide(final float other) { return (FloatBinding) Bindings.divide(this, other); } @Override public LongBinding divide(final long other) { return (LongBinding) Bindings.divide(this, other); } @Override public LongBinding divide(final int other) { return (LongBinding) Bindings.divide(this, other); }
Creates an ObjectExpression that holds the value of this LongExpression. If the value of this LongExpression changes, the value of the ObjectExpression will be updated automatically.
Returns:the new ObjectExpression
Since:JavaFX 8.0
/** * Creates an {@link javafx.beans.binding.ObjectExpression} that holds the value * of this {@code LongExpression}. If the * value of this {@code LongExpression} changes, the value of the * {@code ObjectExpression} will be updated automatically. * * @return the new {@code ObjectExpression} * @since JavaFX 8.0 */
public ObjectExpression<Long> asObject() { return new ObjectBinding<Long>() { { bind(LongExpression.this); } @Override public void dispose() { unbind(LongExpression.this); } @Override protected Long computeValue() { return LongExpression.this.getValue(); } }; } }