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- /*
- * Copyright 2000-2014 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.util;
-
- import com.vaadin.data.Property;
- import com.vaadin.data.Property.ValueChangeEvent;
- import com.vaadin.data.Property.ValueChangeNotifier;
-
- /**
- * Wrapper class that helps implement two-phase commit for a non-transactional
- * property.
- *
- * When accessing the property through the wrapper, getting and setting the
- * property value take place immediately. However, the wrapper keeps track of
- * the old value of the property so that it can be set for the property in case
- * of a roll-back. This can result in the underlying property value changing
- * multiple times (first based on modifications made by the application, then
- * back upon roll-back).
- *
- * Value change events on the {@link TransactionalPropertyWrapper} are only
- * fired at the end of a successful transaction, whereas listeners attached to
- * the underlying property may receive multiple value change events.
- *
- * @see com.vaadin.data.Property.Transactional
- *
- * @author Vaadin Ltd
- * @since 7.0
- *
- * @param <T>
- */
- public class TransactionalPropertyWrapper<T> extends AbstractProperty<T>
- implements ValueChangeNotifier, Property.Transactional<T> {
-
- private Property<T> wrappedProperty;
- private boolean inTransaction = false;
- private boolean valueChangePending;
- private T valueBeforeTransaction;
- private final ValueChangeListener listener = new ValueChangeListener() {
-
- @Override
- public void valueChange(ValueChangeEvent event) {
- fireValueChange();
- }
- };
-
- public TransactionalPropertyWrapper(Property<T> wrappedProperty) {
- this.wrappedProperty = wrappedProperty;
- if (wrappedProperty instanceof ValueChangeNotifier) {
- ((ValueChangeNotifier) wrappedProperty)
- .addValueChangeListener(listener);
- }
- }
-
- /**
- * Removes the ValueChangeListener from wrapped Property that was added by
- * TransactionalPropertyWrapper.
- *
- * @since 7.1.15
- */
- public void detachFromProperty() {
- if (wrappedProperty instanceof ValueChangeNotifier) {
- ((ValueChangeNotifier) wrappedProperty)
- .removeValueChangeListener(listener);
- }
- }
-
- @Override
- public Class getType() {
- return wrappedProperty.getType();
- }
-
- @Override
- public T getValue() {
- return wrappedProperty.getValue();
- }
-
- @Override
- public void setValue(T newValue) throws ReadOnlyException {
- // Causes a value change to be sent to this listener which in turn fires
- // a new value change event for this property
- wrappedProperty.setValue(newValue);
- }
-
- @Override
- public void startTransaction() {
- inTransaction = true;
- valueBeforeTransaction = getValue();
- }
-
- @Override
- public void commit() {
- endTransaction();
- }
-
- @Override
- public void rollback() {
- try {
- wrappedProperty.setValue(valueBeforeTransaction);
- } finally {
- valueChangePending = false;
- endTransaction();
- }
- }
-
- protected void endTransaction() {
- inTransaction = false;
- valueBeforeTransaction = null;
- if (valueChangePending) {
- fireValueChange();
- }
- }
-
- @Override
- protected void fireValueChange() {
- if (inTransaction) {
- valueChangePending = true;
- } else {
- super.fireValueChange();
- }
- }
-
- public Property<T> getWrappedProperty() {
- return wrappedProperty;
- }
-
- @Override
- public boolean isReadOnly() {
- return wrappedProperty.isReadOnly();
- }
-
- @Override
- public void setReadOnly(boolean newStatus) {
- boolean oldStatus = isReadOnly();
- wrappedProperty.setReadOnly(newStatus);
- if (oldStatus != isReadOnly()) {
- fireReadOnlyStatusChange();
- }
- }
-
- }
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