001package org.apache.commons.digester3.binder;
002
003/*
004 * Licensed to the Apache Software Foundation (ASF) under one
005 * or more contributor license agreements.  See the NOTICE file
006 * distributed with this work for additional information
007 * regarding copyright ownership.  The ASF licenses this file
008 * to you under the Apache License, Version 2.0 (the
009 * "License"); you may not use this file except in compliance
010 * with the License.  You may obtain a copy of the License at
011 *
012 *   http://www.apache.org/licenses/LICENSE-2.0
013 *
014 * Unless required by applicable law or agreed to in writing,
015 * software distributed under the License is distributed on an
016 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
017 * KIND, either express or implied.  See the License for the
018 * specific language governing permissions and limitations
019 * under the License.
020 */
021
022import org.apache.commons.digester3.FactoryCreateRule;
023import org.apache.commons.digester3.ObjectCreationFactory;
024
025/**
026 * Builder chained when invoking {@link LinkedRuleBuilder#factoryCreate()}.
027 *
028 * @since 3.0
029 */
030public final class FactoryCreateBuilder
031    extends AbstractBackToLinkedRuleBuilder<FactoryCreateRule>
032{
033
034    private final ClassLoader classLoader;
035
036    private Class<? extends ObjectCreationFactory<?>> type;
037
038    private String attributeName;
039
040    private boolean ignoreCreateExceptions;
041
042    private ObjectCreationFactory<?> creationFactory;
043
044    FactoryCreateBuilder( String keyPattern, String namespaceURI, RulesBinder mainBinder,
045                          LinkedRuleBuilder mainBuilder, ClassLoader classLoader )
046    {
047        super( keyPattern, namespaceURI, mainBinder, mainBuilder );
048        this.classLoader = classLoader;
049    }
050
051    /**
052     * Construct a factory create rule that will use the specified class name to create an {@link ObjectCreationFactory}
053     * which will then be used to create an object and push it on the stack.
054     *
055     * @param className Java class name of the object creation factory class
056     * @return this builder instance
057     */
058    @SuppressWarnings( "unchecked" ) // if class not assignable, will be notified via exception
059    public FactoryCreateBuilder ofType( String className )
060    {
061        if ( className == null )
062        {
063            reportError( "factoryCreate().ofType( String )", "NULL Java type not allowed" );
064        }
065
066        try
067        {
068            Class<?> type = this.classLoader.loadClass( className );
069            if ( !ObjectCreationFactory.class.isAssignableFrom( type ) )
070            {
071                reportError( "factoryCreate().ofType( String )", "NULL Java type not allowed" );
072                return this;
073            }
074
075            this.type = (Class<? extends ObjectCreationFactory<?>>) type;
076        }
077        catch ( ClassNotFoundException e )
078        {
079            reportError( "factoryCreate().ofType( String )", String.format( "class '%s' cannot be load", className ) );
080        }
081
082        return this;
083    }
084
085    /**
086     * Construct a factory create rule that will use the specified class to create an {@link ObjectCreationFactory}
087     * which will then be used to create an object and push it on the stack.
088     *
089     * @param type Java class of the object creation factory class
090     * @return this builder instance
091     */
092    public FactoryCreateBuilder ofType( Class<? extends ObjectCreationFactory<?>> type )
093    {
094        if ( type == null )
095        {
096            reportError( "factoryCreate().ofType( Class<? extends ObjectCreationFactory<?>> )",
097                              "NULL Java type not allowed" );
098        }
099
100        this.type = type;
101
102        return this;
103    }
104
105    /**
106     * Construct a factory create rule using the given, already instantiated, {@link ObjectCreationFactory}.
107     *
108     * @param <T> the type of created object by the given factory
109     * @param creationFactory called on to create the object
110     * @return this builder instance
111     */
112    public <T> FactoryCreateBuilder usingFactory( /* @Nullable */ObjectCreationFactory<T> creationFactory )
113    {
114        this.creationFactory = creationFactory;
115        return this;
116    }
117
118    /**
119     * Allows specify the attribute containing an override class name if it is present.
120     *
121     * @param attributeName The attribute containing an override class name if it is present
122     * @return this builder instance
123     */
124    public FactoryCreateBuilder overriddenByAttribute( /* @Nullable */String attributeName )
125    {
126        this.attributeName = attributeName;
127        return this;
128    }
129
130    /**
131     * Exceptions thrown by the object creation factory will be ignored or not.
132     *
133     * @param ignoreCreateExceptions if true, exceptions thrown by the object creation factory will be ignored
134     * @return this builder instance
135     */
136    public FactoryCreateBuilder ignoreCreateExceptions( boolean ignoreCreateExceptions )
137    {
138        this.ignoreCreateExceptions = ignoreCreateExceptions;
139        return this;
140    }
141
142    /**
143     * {@inheritDoc}
144     */
145    @Override
146    protected FactoryCreateRule createRule()
147    {
148        if ( type == null && attributeName == null && creationFactory == null )
149        {
150            reportError( "factoryCreate()",
151                         "at least one between 'className', 'attributeName' or 'creationFactory' has to be specified" );
152        }
153
154        if ( type != null || attributeName != null )
155        {
156            return new FactoryCreateRule( type, attributeName, ignoreCreateExceptions );
157        }
158
159        return new FactoryCreateRule( creationFactory, ignoreCreateExceptions );
160    }
161
162}