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/*
* Copyright 2000-2018 Vaadin Ltd.
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may not
* use this file except in compliance with the License. You may obtain a copy of
* the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations under
* the License.
*/
package com.vaadin.data;
import com.vaadin.server.SerializableConsumer;
import com.vaadin.shared.Registration;
import com.vaadin.ui.Label;
import java.io.Serializable;
import java.util.LinkedHashSet;
import java.util.Objects;
/**
* Generic {@link HasValue} to use any type of component with Vaadin data binding.
* <p>
* Example:
* <pre>
* Label label = new Label();
* ReadOnlyHasValue<String> hasValue = new ReadOnlyHasValue<>(label::setCaption);
* binder.forField(hasValue).bind(SomeBean::getName);
* </pre>
*
* @param <V> the value type
* @since
*/
public class ReadOnlyHasValue<V> implements HasValue<V>, Serializable {
private V value;
private final SerializableConsumer<V> valueProcessor;
private final V emptyValue;
private LinkedHashSet<ValueChangeListener<V>> listenerList;
/**
* Creates new {@code ReadOnlyHasValue}
*
* @param valueProcessor the value valueProcessor, e.g. {@link Label#setValue}
* @param emptyValue the value to be used as empty, {@code null} by default
*/
public ReadOnlyHasValue(SerializableConsumer<V> valueProcessor, V emptyValue) {
this.valueProcessor = valueProcessor;
this.emptyValue = emptyValue;
}
/**
* Creates new {@code ReadOnlyHasValue} with {@code null} as an empty value.
*
* @param valueProcessor the value valueProcessor, e.g. {@link Label#setValue}
*/
public ReadOnlyHasValue(SerializableConsumer<V> valueProcessor) {
this(valueProcessor,null);
}
@Override
public void setValue(V value) {
V oldValue = this.value;
this.value = value;
valueProcessor.accept(value);
if (listenerList != null && ! Objects.equals(oldValue, value)) {
for (ValueChangeListener<V> valueChangeListener : listenerList) {
valueChangeListener.valueChange(
new ValueChangeEvent<>(null, this, oldValue, false));
}
}
}
@Override
public V getValue() {
return value;
}
@Override
public Registration addValueChangeListener(
ValueChangeListener<V> listener) {
Objects.requireNonNull(listener, "Listener must not be null.");
if (listenerList == null) {
listenerList = new LinkedHashSet<>();
}
listenerList.add(listener);
return () -> listenerList.remove(listener);
}
@Override
public boolean isRequiredIndicatorVisible() {
return false;
}
@Override
public void setRequiredIndicatorVisible(boolean requiredIndicatorVisible) {
if (requiredIndicatorVisible) throw new IllegalArgumentException("Not Writable");
}
@Override
public void setReadOnly(boolean readOnly) {
if (!readOnly) throw new IllegalArgumentException("Not Writable");
}
@Override
public boolean isReadOnly() {
return true;
}
@Override
public V getEmptyValue() {
return emptyValue;
}
}
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