/*

 * Copyright (c) 1997, 2011, Oracle and/or its affiliates. All rights reserved.

 * 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 java.util.Collection;

import java.util.Collections;

import javax.xml.bind.Unmarshaller;

import javax.xml.bind.ValidationEvent;

import javax.xml.bind.helpers.ValidationEventImpl;

import javax.xml.namespace.QName;

import com.sun.xml.internal.bind.v2.runtime.JaxBeanInfo;

import org.xml.sax.SAXException;

/**

 * @author Kohsuke Kawaguchi

 */

public abstract class Loader {

    // allow derived classes to change it later

    protected boolean expectText;

    protected Loader(boolean expectText) {

        this.expectText = expectText;

    }

    protected Loader() {

    }

//

//

//

// Contract

//

//

//

    /**

     * Called when the loader is activated, which is when a new start tag is seen

     * and when the parent designated this loader as the child loader.

     *

     * <p>

     * The callee may change <tt>state.loader</tt> to designate another {@link Loader}

     * for the processing. It's the responsibility of the callee to forward the startElement

     * event in such a case.

     *

     * @param ea

     *      info about the start tag. never null.

     */

    public void startElement(UnmarshallingContext.State state,TagName ea) throws SAXException {

    }

    /**

     * Called when this loaderis an active loaderand we see a new child start tag.

     *

     * <p>

     * The callee is expected to designate another loaderas a loaderthat processes

     * this element, then it should also register a {@link Receiver}.

     * The designated loaderwill become an active loader.

     *

     * <p>

     * The default implementation reports an error saying an element is unexpected.

     */

    public void childElement(UnmarshallingContext.State state, TagName ea) throws SAXException {

        // notify the error, then recover by ignoring the whole element.

        reportUnexpectedChildElement(ea, true);

        state.loader = Discarder.INSTANCE;

        state.receiver = null;

    }

    @SuppressWarnings({"StringEquality"})

    protected final void reportUnexpectedChildElement(TagName ea, boolean canRecover) throws SAXException {

            // this error happens particurly often (when input documents contain a lot of unexpected elements to be ignored),

            // so don't bother computing all the messages and etc if we know that

            // there's no event handler to receive the error in the end. See #286

        if(ea.uri!=ea.uri.intern() || ea.local!=ea.local.intern())

            reportError(Messages.UNINTERNED_STRINGS.format(), canRecover );

        else

            reportError(Messages.UNEXPECTED_ELEMENT.format(ea.uri,ea.local,computeExpectedElements()), canRecover );

    }

    /**

     * Returns a set of tag names expected as possible child elements in this context.

     */

    public Collection<QName> getExpectedChildElements() {

        return Collections.emptyList();

    }

    /**

     * Returns a set of tag names expected as possible child elements in this context.

     */

    public Collection<QName> getExpectedAttributes() {

        return Collections.emptyList();

    }

    /**

     * Called when this loaderis an active loaderand we see a chunk of text.

     *

     * The runtime makes sure that adjacent characters (even those separated

     * by comments, PIs, etc) are reported as one event.

     * IOW, you won't see two text event calls in a row.

     */

    public void text(UnmarshallingContext.State state, CharSequence text) throws SAXException {

        // make str printable

        text = text.toString().replace('\r',' ').replace('\n',' ').replace('\t',' ').trim();

        reportError(Messages.UNEXPECTED_TEXT.format(text), true );

    }

    /**

     * True if this loader expects the {@link #text(UnmarshallingContext.State, CharSequence)} method

     * to be called. False otherwise.

     */

    public final boolean expectText() {

        return expectText;

    }

    /**

     * Called when this loaderis an active loaderand we see an end tag.

     */

    public void leaveElement(UnmarshallingContext.State state, TagName ea) throws SAXException {

    }

//

//

//

// utility methods

//

//

//

    /**

     * Computes the names of possible root elements for a better error diagnosis.

     */

    private String computeExpectedElements() {

        StringBuilder r = new StringBuilder();

        for( QName n : getExpectedChildElements() ) {

            if(r.length()!=0)   r.append(',');

            r.append("<{").append(n.getNamespaceURI()).append('}').append(n.getLocalPart()).append('>');

        }

        if(r.length()==0) {

            return "(none)";

        }

        return r.toString();

    }

    /**

     * Fires the beforeUnmarshal event if necessary.

     *

     * @param state

     *      state of the newly create child object.

     */

    protected final void fireBeforeUnmarshal(JaxBeanInfo beanInfo, Object child, UnmarshallingContext.State state) throws SAXException {

        if(beanInfo.lookForLifecycleMethods()) {

            UnmarshallingContext context = state.getContext();

            Unmarshaller.Listener listener = context.parent.getListener();

            if(beanInfo.hasBeforeUnmarshalMethod()) {

                beanInfo.invokeBeforeUnmarshalMethod(context.parent, child, state.prev.target);

            }

            if(listener!=null) {

                listener.beforeUnmarshal(child, state.prev.target);

            }

        }

    }

    /**

     * Fires the afterUnmarshal event if necessary.

     *

     * @param state

     *      state of the parent object

     */

    protected final void fireAfterUnmarshal(JaxBeanInfo beanInfo, Object child, UnmarshallingContext.State state) throws SAXException {

        // fire the event callback

        if(beanInfo.lookForLifecycleMethods()) {

            UnmarshallingContext context = state.getContext();

            Unmarshaller.Listener listener = context.parent.getListener();

            if(beanInfo.hasAfterUnmarshalMethod()) {

                beanInfo.invokeAfterUnmarshalMethod(context.parent, child, state.target);

            }

            if(listener!=null)

                listener.afterUnmarshal(child, state.target);

        }

    }

    /**

     * Last resort when something goes terribly wrong within the unmarshaller.

     */

    protected static void handleGenericException(Exception e) throws SAXException {

        handleGenericException(e,false);

    }

    public static void handleGenericException(Exception e, boolean canRecover) throws SAXException {

        reportError(e.getMessage(), e, canRecover );

    }

    public static void handleGenericError(Error e) throws SAXException {

        reportError(e.getMessage(), false);

    }

    protected static void reportError(String msg, boolean canRecover) throws SAXException {

        reportError(msg, null, canRecover );

    }

    public static void reportError(String msg, Exception nested, boolean canRecover) throws SAXException {

        UnmarshallingContext context = UnmarshallingContext.getInstance();

        context.handleEvent( new ValidationEventImpl(

            canRecover? ValidationEvent.ERROR : ValidationEvent.FATAL_ERROR,

            msg,

            context.getLocator().getLocation(),

            nested ), canRecover );

    }

    /**

     * This method is called by the generated derived class

     * when a datatype parse method throws an exception.

     */

    protected static void handleParseConversionException(UnmarshallingContext.State state, Exception e) throws SAXException {

        // wrap it into a ParseConversionEvent and report it

        state.getContext().handleError(e);

    }

}