de.csenk.gwt.commons.editor.client.AutoFlushInitializer.java Source code

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Here is the source code for de.csenk.gwt.commons.editor.client.AutoFlushInitializer.java

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/*
 * Copyright 2012 Christian Senk
 * 
 * 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 de.csenk.gwt.commons.editor.client;

import java.util.Collection;

import com.google.gwt.editor.client.Editor;
import com.google.gwt.editor.client.EditorContext;
import com.google.gwt.editor.client.LeafValueEditor;
import com.google.gwt.editor.client.ValueAwareEditor;
import com.google.gwt.editor.client.impl.Initializer;
import com.google.gwt.event.logical.shared.HasValueChangeHandlers;
import com.google.gwt.event.logical.shared.ValueChangeEvent;
import com.google.gwt.event.logical.shared.ValueChangeHandler;
import com.google.gwt.event.shared.HandlerRegistration;

import de.csenk.gwt.commons.editor.shared.AutoFlushBeanEditorDriver;
import de.csenk.gwt.commons.editor.shared.FlushEvent;

/**
 * @author senk.christian@googlemail.com
 */
public class AutoFlushInitializer extends Initializer {

    private final Collection<HandlerRegistration> handlerRegistrations;
    protected final AutoFlushBeanEditorDriver<?, ?> driver;

    /**
     * @param handlerRegistrations
     */
    public AutoFlushInitializer(Collection<HandlerRegistration> handlerRegistrations,
            AutoFlushBeanEditorDriver<?, ?> driver) {
        this.handlerRegistrations = handlerRegistrations;
        this.driver = driver;
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public <Q> boolean visit(EditorContext<Q> ctx) {
        final HasValueChangeHandlers<Q> editor = asHasValueChangeHandlers(ctx.getEditor());
        if (editor != null) {
            handlerRegistrations.add(editor.addValueChangeHandler(createValueChangeHandler(ctx)));
        }

        return super.visit(ctx);
    }

    /**
     * @param ctx
     * @return
     */
    private <Q> ValueChangeHandler<Q> createValueChangeHandler(final EditorContext<Q> ctx) {
        return new ValueChangeHandler<Q>() {

            @Override
            public void onValueChange(ValueChangeEvent<Q> event) {
                flush(ctx);
                driver.fireEvent(new FlushEvent());
            }

        };
    }

    /**
     * @see com.google.gwt.editor.client.impl.Flusher.endVisit(EditorContext<Q> ctx)
     * @param ctx
     */
    protected <Q> void flush(EditorContext<Q> ctx) {
        // Flush ValueAware editors
        final ValueAwareEditor<Q> asValue = ctx.asValueAwareEditor();
        if (asValue != null) {
            asValue.flush();
        }

        // Pull value from LeafValueEditors and update edited object
        final LeafValueEditor<Q> asLeaf = ctx.asLeafValueEditor();
        if (asLeaf != null && ctx.canSetInModel()) {
            ctx.setInModel(asLeaf.getValue());
        }
    }

    /**
     * @param editor
     * @return
     */
    @SuppressWarnings("unchecked")
    private <Q> HasValueChangeHandlers<Q> asHasValueChangeHandlers(final Editor<Q> editor) {
        if (editor instanceof HasValueChangeHandlers)
            return (HasValueChangeHandlers<Q>) editor;

        return null;
    }

}