/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.apache.tomcat.util.digester;

import org.xml.sax.Attributes;


Rule implementation that uses an ObjectCreationFactory to create a new object which it pushes onto the object stack. When the element is complete, the object will be popped.
This rule is intended in situations where the element's attributes are
needed before the object can be created.  A common scenario is for the
ObjectCreationFactory implementation to use the attributes  as parameters
in a call to either a factory method or to a non-empty constructor.
/**
 * <p>Rule implementation that uses an {@link ObjectCreationFactory} to create
 * a new object which it pushes onto the object stack.  When the element is
 * complete, the object will be popped.</p>
 *
 * <p>This rule is intended in situations where the element's attributes are
 * needed before the object can be created.  A common scenario is for the
 * ObjectCreationFactory implementation to use the attributes  as parameters
 * in a call to either a factory method or to a non-empty constructor.
 */

public class FactoryCreateRule extends Rule {

    // ----------------------------------------------------------- Fields

    
Should exceptions thrown by the factory be ignored? /** Should exceptions thrown by the factory be ignored? */
    private boolean ignoreCreateExceptions;
    
Stock to manage /** Stock to manage */
    private ArrayStack<Boolean> exceptionIgnoredStack;


    // ----------------------------------------------------------- Constructors

    
Construct a factory create rule using the given, already instantiated, ObjectCreationFactory. 
Params:
creationFactory – called on to create the object.
ignoreCreateExceptions – if true, exceptions thrown by the object
 creation factory will be ignored./**
     * Construct a factory create rule using the given, already instantiated,
     * {@link ObjectCreationFactory}.
     *
     * @param creationFactory called on to create the object.
     * @param ignoreCreateExceptions if true, exceptions thrown by the object
     *  creation factory will be ignored.
     */
    public FactoryCreateRule(
                            ObjectCreationFactory creationFactory,
                            boolean ignoreCreateExceptions) {

        this.creationFactory = creationFactory;
        this.ignoreCreateExceptions = ignoreCreateExceptions;
    }


    // ----------------------------------------------------- Instance Variables

    
The object creation factory we will use to instantiate objects
as required based on the attributes specified in the matched XML
element.
/**
     * The object creation factory we will use to instantiate objects
     * as required based on the attributes specified in the matched XML
     * element.
     */
    protected ObjectCreationFactory creationFactory = null;


    // --------------------------------------------------------- Public Methods


    
Process the beginning of this element.
Params:
attributes – The attribute list of this element/**
     * Process the beginning of this element.
     *
     * @param attributes The attribute list of this element
     */
    @Override
    public void begin(String namespace, String name, Attributes attributes) throws Exception {

        if (ignoreCreateExceptions) {

            if (exceptionIgnoredStack == null) {
                exceptionIgnoredStack = new ArrayStack<>();
            }

            try {
                Object instance = creationFactory.createObject(attributes);

                if (digester.log.isDebugEnabled()) {
                    digester.log.debug("[FactoryCreateRule]{" + digester.match +
                            "} New " + instance.getClass().getName());
                }
                digester.push(instance);
                exceptionIgnoredStack.push(Boolean.FALSE);

            } catch (Exception e) {
                // log message and error
                if (digester.log.isInfoEnabled()) {
                    digester.log.info(sm.getString("rule.createError",
                        ((e.getMessage() == null) ? e.getClass().getName() : e.getMessage())));
                    if (digester.log.isDebugEnabled()) {
                        digester.log.debug("[FactoryCreateRule] Ignored exception:", e);
                    }
                }
                exceptionIgnoredStack.push(Boolean.TRUE);
            }

        } else {
            Object instance = creationFactory.createObject(attributes);

            if (digester.log.isDebugEnabled()) {
                digester.log.debug("[FactoryCreateRule]{" + digester.match +
                        "} New " + instance.getClass().getName());
            }
            digester.push(instance);
        }
    }


    
Process the end of this element.
/**
     * Process the end of this element.
     */
    @Override
    public void end(String namespace, String name) throws Exception {

        // check if object was created
        // this only happens if an exception was thrown and we're ignoring them
        if (
                ignoreCreateExceptions &&
                exceptionIgnoredStack != null &&
                !(exceptionIgnoredStack.empty())) {

            if ((exceptionIgnoredStack.pop()).booleanValue()) {
                // creation exception was ignored
                // nothing was put onto the stack
                if (digester.log.isTraceEnabled()) {
                    digester.log.trace("[FactoryCreateRule] No creation so no push so no pop");
                }
                return;
            }
        }

        Object top = digester.pop();
        if (digester.log.isDebugEnabled()) {
            digester.log.debug("[FactoryCreateRule]{" + digester.match +
                    "} Pop " + top.getClass().getName());
        }

    }


    
Clean up after parsing is complete.
/**
     * Clean up after parsing is complete.
     */
    @Override
    public void finish() throws Exception {
        // NO-OP
    }


    
Render a printable version of this Rule.
/**
     * Render a printable version of this Rule.
     */
    @Override
    public String toString() {
        StringBuilder sb = new StringBuilder("FactoryCreateRule[");
        if (creationFactory != null) {
            sb.append("creationFactory=");
            sb.append(creationFactory);
        }
        sb.append("]");
        return sb.toString();
    }
}