/*

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package com.sun.xml.internal.bind.v2.runtime.unmarshaller;

import com.sun.xml.internal.bind.api.AccessorException;

import com.sun.xml.internal.bind.v2.runtime.reflect.Accessor;

import com.sun.xml.internal.bind.v2.runtime.reflect.Lister;

import org.xml.sax.SAXException;

/**

 * Holds the information about packing scope.

 *

 * <p>

 * When no packing is started yet, all the fields should be set to null.

 *

 * @author Kohsuke Kawaguchi

 */

public final class Scope<BeanT,PropT,ItemT,PackT> {

    public final UnmarshallingContext context;

    private BeanT bean;

    private Accessor<BeanT,PropT> acc;

    private PackT pack;

    private Lister<BeanT,PropT,ItemT,PackT> lister;

    Scope(UnmarshallingContext context) {

        this.context = context;

    }

    /**

     * Returns true if this scope object is filled by a packing in progress.

     */

    public boolean hasStarted() {

        return bean!=null;

    }

    /**

     * Initializes all the fields to null.

     */

    public void reset() {

        if(bean==null) {

            // already initialized

            assert clean();

            return;

        }

        bean = null;

        acc = null;

        pack = null;

        lister = null;

    }

    /**

     * Finishes up the current packing in progress (if any) and

     * resets this object.

     */

    public void finish() throws AccessorException {

        if(hasStarted()) {

            lister.endPacking(pack,bean,acc);

            reset();

        }

        assert clean();

    }

    private boolean clean() {

        return bean==null && acc==null && pack==null && lister==null;

    }

    /**

     * Adds a new item to this packing scope.

     */

    public void add( Accessor<BeanT,PropT> acc, Lister<BeanT,PropT,ItemT,PackT> lister, ItemT value) throws SAXException{

        try {

            if(!hasStarted()) {

                this.bean = (BeanT)context.getCurrentState().target;

                this.acc = acc;

                this.lister = lister;

                this.pack = lister.startPacking(bean,acc);

            }

            lister.addToPack(pack,value);

        } catch (AccessorException e) {

            Loader.handleGenericException(e,true);

            // recover from this error by ignoring future items.

            this.lister = Lister.getErrorInstance();

            this.acc = Accessor.getErrorInstance();

        }

    }

    /**

     * Starts the packing scope, without adding any item.

     *

     * This allows us to return an empty pack, thereby allowing the user

     * to distinguish empty array vs null array.

     */

    public void start( Accessor<BeanT,PropT> acc, Lister<BeanT,PropT,ItemT,PackT> lister) throws SAXException{

        try {

            if(!hasStarted()) {

                this.bean = (BeanT)context.getCurrentState().target;

                this.acc = acc;

                this.lister = lister;

                this.pack = lister.startPacking(bean,acc);

            }

        } catch (AccessorException e) {

            Loader.handleGenericException(e,true);

            // recover from this error by ignoring future items.

            this.lister = Lister.getErrorInstance();

            this.acc = Accessor.getErrorInstance();

        }

    }

}