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This is the master POM file for Sun's Implementation of the JSF 2.1 Specification.
There is a newer version: 2.2.20
/*
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 *
 * Copyright (c) 1997-2010 Oracle and/or its affiliates. All rights reserved.
 *
 * The contents of this file are subject to the terms of either the GNU
 * General Public License Version 2 only ("GPL") or the Common Development
 * and Distribution License("CDDL") (collectively, the "License").  You
 * may not use this file except in compliance with the License.  You can
 * obtain a copy of the License at
 * https://glassfish.dev.java.net/public/CDDL+GPL_1_1.html
 * or packager/legal/LICENSE.txt.  See the License for the specific
 * language governing permissions and limitations under the License.
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 * file and include the License file at packager/legal/LICENSE.txt.
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 * GPL Classpath Exception:
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 * exception as provided by Oracle in the GPL Version 2 section of the License
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 *
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package javax.faces.view;

import java.util.Collection;
import java.util.Collections;
import java.util.ArrayList;
import java.util.List;
import javax.faces.component.UIViewParameter;
import javax.faces.component.UIViewRoot;
import javax.faces.component.UIComponent;
import javax.faces.context.FacesContext;

/**
 *  ViewMetadata is
 * reponsible for extracting and providing view parameter metadata from
 * VDL views.  Because {@link ViewDeclarationLanguage#getViewMetadata}
 * is required to return null for JSP views and
 * non-null for views authored in Facelets for JSF 2, this
 * specification only applys to Facelets for JSF 2.  
 *
 * @since 2.0
 */
public abstract class ViewMetadata {


    /**
     * 
     * @return the view ID for which this ViewMetadata instance
     *  was created
     */
    public abstract String getViewId();


    /**
     * 
 Creates a new {@link UIViewRoot}
     * containing only view parameter metadata.  The processing of
     * building this UIViewRoot with metadata should not
     * cause any events to be published to the application.  The
     * implementation must call {@link FacesContext#setProcessingEvents}
     * passing false as the argument, at the beginning of
     * the method, and pass true to the same method at the
     * end.  The implementation must ensure that this happens regardless
     * of ant exceptions that may be thrown.
     *
     * @param context the {@link FacesContext} for the current request
     * @return a UIViewRoot containing only view parameter metadata
     *  (if any)
     */
    public abstract UIViewRoot createMetadataView(FacesContext context);


    /**
     *  Utility method to extract view
     * metadata from the provided {@link UIViewRoot}.  
     *
     * @param root the {@link UIViewRoot} from which the metadata will
     * be extracted from
     *
     * @return a Collection of {@link UIViewParameter}
     * instances.  If the view has no metadata, the collection will be
     * empty.
     */
    public static Collection getViewParameters(UIViewRoot root) {

        Collection params;
        UIComponent metadataFacet = root.getFacet(UIViewRoot.METADATA_FACET_NAME);

        if (metadataFacet == null) {
            params = Collections.emptyList();
        } else {
            params = new ArrayList();
            List children = metadataFacet.getChildren();
            int len = children.size();
            for (int i = 0; i < len; i++) {
                UIComponent c = children.get(i);
                if (c instanceof UIViewParameter) {
                    params.add((UIViewParameter) c);
                }
            }
        }

        return params;

    }


}