53 * @param <E> the type of the {@code List} elements.
54 * @since JavaFX 2.1
55 */
56 public abstract class ListExpression<E> implements ObservableListValue<E> {
57
58 private static final ObservableList EMPTY_LIST = FXCollections.emptyObservableList();
59
60 @Override
61 public ObservableList<E> getValue() {
62 return get();
63 }
64
65 /**
66 * Returns a {@code ListExpression} that wraps a
67 * {@link javafx.beans.value.ObservableListValue}. If the
68 * {@code ObservableListValue} is already a {@code ListExpression}, it
69 * will be returned. Otherwise a new
70 * {@link javafx.beans.binding.ListBinding} is created that is bound to
71 * the {@code ObservableListValue}.
72 *
73 * @param value
74 * The source {@code ObservableListValue}
75 * @return A {@code ListExpression} that wraps the
76 * {@code ObservableListValue} if necessary
77 * @throws NullPointerException
78 * if {@code value} is {@code null}
79 */
80 public static <E> ListExpression<E> listExpression(final ObservableListValue<E> value) {
81 if (value == null) {
82 throw new NullPointerException("List must be specified.");
83 }
84 return value instanceof ListExpression ? (ListExpression<E>) value
85 : new ListBinding<E>() {
86 {
87 super.bind(value);
88 }
89
90 @Override
91 public void dispose() {
92 super.unbind(value);
93 }
94
95 @Override
96 protected ObservableList<E> computeValue() {
97 return value.get();
98 }
99
100 @Override
101 public ObservableList<ObservableListValue<E>> getDependencies() {
102 return FXCollections.singletonObservableList(value);
103 }
104 };
105 }
106
107 /**
108 * The size of the list
109 */
110 public int getSize() {
111 return size();
112 }
113
114 /**
115 * An integer property that represents the size of the list.
116 * @return the property
117 */
118 public abstract ReadOnlyIntegerProperty sizeProperty();
119
120 /**
121 * A boolean property that is {@code true}, if the list is empty.
122 */
123 public abstract ReadOnlyBooleanProperty emptyProperty();
124
125 /**
126 * Creates a new {@link ObjectBinding} that contains the element at the specified position.
127 * If {@code index} points behind the list, the {@code ObjectBinding} contains {@code null}.
128 *
129 * @param index the index of the element
130 * @return the {@code ObjectBinding}
131 * @throws IllegalArgumentException if {@code index < 0}
132 */
133 public ObjectBinding<E> valueAt(int index) {
134 return Bindings.valueAt(this, index);
135 }
136
137 /**
138 * Creates a new {@link ObjectBinding} that contains the element at the specified position.
139 * If {@code index} points outside of the list, the {@code ObjectBinding} contains {@code null}.
140 *
141 * @param index the index of the element
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53 * @param <E> the type of the {@code List} elements.
54 * @since JavaFX 2.1
55 */
56 public abstract class ListExpression<E> implements ObservableListValue<E> {
57
58 private static final ObservableList EMPTY_LIST = FXCollections.emptyObservableList();
59
60 @Override
61 public ObservableList<E> getValue() {
62 return get();
63 }
64
65 /**
66 * Returns a {@code ListExpression} that wraps a
67 * {@link javafx.beans.value.ObservableListValue}. If the
68 * {@code ObservableListValue} is already a {@code ListExpression}, it
69 * will be returned. Otherwise a new
70 * {@link javafx.beans.binding.ListBinding} is created that is bound to
71 * the {@code ObservableListValue}.
72 *
73 * @param <E> the type of the wrapped {@code List}
74 * @param value
75 * The source {@code ObservableListValue}
76 * @return A {@code ListExpression} that wraps the
77 * {@code ObservableListValue} if necessary
78 * @throws NullPointerException
79 * if {@code value} is {@code null}
80 */
81 public static <E> ListExpression<E> listExpression(final ObservableListValue<E> value) {
82 if (value == null) {
83 throw new NullPointerException("List must be specified.");
84 }
85 return value instanceof ListExpression ? (ListExpression<E>) value
86 : new ListBinding<E>() {
87 {
88 super.bind(value);
89 }
90
91 @Override
92 public void dispose() {
93 super.unbind(value);
94 }
95
96 @Override
97 protected ObservableList<E> computeValue() {
98 return value.get();
99 }
100
101 @Override
102 public ObservableList<ObservableListValue<E>> getDependencies() {
103 return FXCollections.singletonObservableList(value);
104 }
105 };
106 }
107
108 /**
109 * The size of the list
110 * @return the size
111 */
112 public int getSize() {
113 return size();
114 }
115
116 /**
117 * An integer property that represents the size of the list.
118 * @return the property
119 */
120 public abstract ReadOnlyIntegerProperty sizeProperty();
121
122 /**
123 * A boolean property that is {@code true}, if the list is empty.
124 * @return the {@code ReadOnlyBooleanProperty}
125 *
126 */
127 public abstract ReadOnlyBooleanProperty emptyProperty();
128
129 /**
130 * Creates a new {@link ObjectBinding} that contains the element at the specified position.
131 * If {@code index} points behind the list, the {@code ObjectBinding} contains {@code null}.
132 *
133 * @param index the index of the element
134 * @return the {@code ObjectBinding}
135 * @throws IllegalArgumentException if {@code index < 0}
136 */
137 public ObjectBinding<E> valueAt(int index) {
138 return Bindings.valueAt(this, index);
139 }
140
141 /**
142 * Creates a new {@link ObjectBinding} that contains the element at the specified position.
143 * If {@code index} points outside of the list, the {@code ObjectBinding} contains {@code null}.
144 *
145 * @param index the index of the element
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