EditableValueHolderStateHelper.java

/*
 * Copyright 2017 OmniFaces
 *
 * 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 org.omnifaces.component;

import java.util.Iterator;
import java.util.Map;

import javax.faces.component.EditableValueHolder;
import javax.faces.component.StateHelper;
import javax.faces.component.UIComponent;
import javax.faces.component.UIComponentBase;
import javax.faces.context.FacesContext;

/**
 * Helper class to save and restore state of an {@link EditableValueHolder}.
 *
 * @author Bauke Scholtz.
 */
public final class EditableValueHolderStateHelper {

	// UIData and UIRepeat have a similar nested class. Too bad that they aren't publicly reusable.

	// Variables ------------------------------------------------------------------------------------------------------

	private Object submittedValue;
	private boolean valid = true;
	private Object localValue;
	private boolean localValueSet;

	// Actions --------------------------------------------------------------------------------------------------------

	/**
	 * Save the state of the given {@link EditableValueHolder}.
	 * @param holder The {@link EditableValueHolder} to save the state for.
	 */
	public void save(EditableValueHolder holder) {
		submittedValue = holder.getSubmittedValue();
		valid = holder.isValid();
		localValue = holder.getLocalValue();
		localValueSet = holder.isLocalValueSet();
	}

	/**
	 * Restore the state of the given {@link EditableValueHolder}.
	 * @param holder The {@link EditableValueHolder} to restore the state for.
	 */
	public void restore(EditableValueHolder holder) {
		holder.setSubmittedValue(submittedValue);
		holder.setValid(valid);
		holder.setValue(localValue);
		holder.setLocalValueSet(localValueSet);
	}

	// Utility --------------------------------------------------------------------------------------------------------

	/**
	 * Save state of any {@link EditableValueHolder} children.
	 * @param context The faces context to work with.
	 * @param stateHelper The state helper of the parent component.
	 * @param children An iterator with all child facets and components of the parent component as obtained by
	 * {@link UIComponentBase#getFacetsAndChildren()}.
	 */
	public static void save(FacesContext context, StateHelper stateHelper, Iterator<UIComponent> children) {
		while (children.hasNext()) {
			UIComponent child = children.next();

			if (child instanceof EditableValueHolder && !child.isTransient()) {
				get(stateHelper, child.getClientId(context)).save((EditableValueHolder) child);
			}

			if (child.getFacetCount() > 0 || child.getChildCount() > 0) {
				save(context, stateHelper, child.getFacetsAndChildren());
			}
		}
	}

	/**
	 * Restore state of any {@link EditableValueHolder} children.
	 * @param context The faces context to work with.
	 * @param stateHelper The state helper of the parent component.
	 * @param children An iterator with all child facets and components of the parent component as obtained by
	 * {@link UIComponentBase#getFacetsAndChildren()}.
	 */
	public static void restore(FacesContext context, StateHelper stateHelper, Iterator<UIComponent> children) {
		while (children.hasNext()) {
			UIComponent child = children.next();
			child.setId(child.getId()); // This implicitly resets the cached client ID. See JSF spec 3.1.6.

			if (child instanceof EditableValueHolder && !child.isTransient()) {
				get(stateHelper, child.getClientId(context)).restore((EditableValueHolder) child);
			}

			if (child.getFacetCount() > 0 || child.getChildCount() > 0) {
				restore(context, stateHelper, child.getFacetsAndChildren());
			}
		}
	}

	/**
	 * Returns the state helper of the {@link EditableValueHolder} child associated with the given client ID.
	 * @param stateHelper The state helper of the parent component.
	 * @param clientId The client ID of the {@link EditableValueHolder} child to return the state helper for.
	 * @return The state helper of the {@link EditableValueHolder} child associated with the given client ID.
	 */
	@SuppressWarnings("unchecked")
	public static EditableValueHolderStateHelper get(StateHelper stateHelper, String clientId) {
		Map<String, EditableValueHolderStateHelper> childState =
			(Map<String, EditableValueHolderStateHelper>) stateHelper.get(EditableValueHolderStateHelper.class);
		EditableValueHolderStateHelper state = null;

		if (childState != null) {
			state = childState.get(clientId);
		}

		if (state == null) {
			state = new EditableValueHolderStateHelper();
			stateHelper.put(EditableValueHolderStateHelper.class, clientId, state);
		}

		return state;
	}

}