001    /**
002     * Licensed to the Apache Software Foundation (ASF) under one or more
003     * contributor license agreements.  See the NOTICE file distributed with
004     * this work for additional information regarding copyright ownership.
005     * The ASF licenses this file to You under the Apache License, Version 2.0
006     * (the "License"); you may not use this file except in compliance with
007     * the License.  You may obtain a copy of the License at
008     *
009     *      http://www.apache.org/licenses/LICENSE-2.0
010     *
011     * Unless required by applicable law or agreed to in writing, software
012     * distributed under the License is distributed on an "AS IS" BASIS,
013     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014     * See the License for the specific language governing permissions and
015     * limitations under the License.
016     */
017    package org.apache.xbean.blueprint.context.impl;
018    
019    import org.apache.aries.blueprint.ParserContext;
020    import org.apache.aries.blueprint.mutable.MutableBeanMetadata;
021    import org.apache.aries.blueprint.mutable.MutableValueMetadata;
022    import org.osgi.service.blueprint.container.ComponentDefinitionException;
023    import org.osgi.service.blueprint.reflect.BeanProperty;
024    
025    import java.lang.reflect.Constructor;
026    import java.lang.reflect.Method;
027    import java.util.ArrayList;
028    import java.util.Arrays;
029    import java.util.Collections;
030    import java.util.Comparator;
031    import java.util.HashMap;
032    import java.util.HashSet;
033    import java.util.LinkedHashMap;
034    import java.util.LinkedList;
035    import java.util.List;
036    import java.util.Map;
037    import java.util.Set;
038    
039    /**
040     * NamedConstructorArgs is a BeanFactoryPostProcessor that converts property declarations into indexed constructor args
041     * based on the the constructor parameter names annotation.  This process first selects a constructor and then fills in
042     * the constructor arguments from the properties defined in the bean definition.  If a property is not defined in the
043     * bean definition, first the defaultValues map is checked for a value and if a value is not present a Java default
044     * value is provided for the constructor argument (e.g. numbers are assigned 0 and objects are assigned null).
045     *
046     * @author Dain Sundstrom
047     * @version $Id$
048     * @since 2.0
049     */
050    public class NamedConstructorArgs {
051        private Map<PropertyKey, String> defaultValues = new HashMap<PropertyKey, String>();
052    
053        /**
054         * Gets the default values that are assigned to constructor arguments without a defined value.
055         *
056         * @return the default values that are assigned to constructor arguments without a defined value
057         */
058        public List<DefaultProperty> getDefaultValues() {
059            List<DefaultProperty> values = new LinkedList<DefaultProperty>();
060            for (Map.Entry<PropertyKey, String> entry : defaultValues.entrySet()) {
061                PropertyKey key = entry.getKey();
062                String value = entry.getValue();
063                values.add(new DefaultProperty(key.name, key.type, value));
064            }
065            return values;
066        }
067    
068        /**
069         * Sets the default values that are assigned to constructor arguments without a defined value.
070         *
071         * @param defaultValues the values that are assigned to constructor arguments without a defined value
072         */
073        public void setDefaultValues(List<DefaultProperty> defaultValues) {
074            this.defaultValues.clear();
075            for (DefaultProperty defaultValue : defaultValues) {
076                addDefaultValue(defaultValue);
077            }
078        }
079    
080        /**
081         * Adds a default value for a property with the specified name and type.
082         *
083         * @param name  the name of the property
084         * @param type  the type of the property
085         * @param value the default value for a property with the specified name and type
086         */
087        public void addDefaultValue(String name, Class type, String value) {
088            defaultValues.put(new PropertyKey(name, type), value);
089        }
090    
091        /**
092         * Adds a defautl value for a property.
093         *
094         * @param defaultProperty the default property information
095         */
096        private void addDefaultValue(DefaultProperty defaultProperty) {
097            defaultValues.put(new PropertyKey(defaultProperty.getName(), defaultProperty.getType()), defaultProperty.getValue());
098        }
099    
100        public void processParameters(MutableBeanMetadata beanMetadata, MappingMetaData metadata, ParserContext parserContext) {
101    
102            // if this bean already has constructor arguments defined, don't mess with them
103            if (beanMetadata.getArguments().size() > 0) {
104                return;
105            }
106    
107            // try to get a list of constructor arg names to use
108            ConstructionInfo constructionInfo = selectConstructionMethod(beanMetadata, metadata);
109            if (constructionInfo == null) {
110                return;
111            }
112    
113            // remove each named property and add an indexed constructor arg
114            List<BeanProperty> beanProperties = beanMetadata.getProperties();
115            LinkedHashMap<String, BeanProperty> propMap = new LinkedHashMap<String, BeanProperty>();
116            for (BeanProperty beanProperty : beanProperties) {
117                propMap.put(beanProperty.getName(), beanProperty);
118            }
119            String[] parameterNames = constructionInfo.parameterNames;
120            Class[] parameterTypes = constructionInfo.parameterTypes;
121            for (int i = 0; i < parameterNames.length; i++) {
122                String parameterName = parameterNames[i];
123                Class parameterType = parameterTypes[i];
124    
125                BeanProperty beanProperty = propMap.get(parameterName);
126                if (beanProperty != null) {
127                    propMap.remove(parameterName);
128                    beanMetadata.removeProperty(beanProperty);
129                    beanMetadata.addArgument(beanProperty.getValue(), parameterType.getName(), i);
130                } else {
131                    String defaultValue = defaultValues.get(new PropertyKey(parameterName, parameterType));
132                    if (defaultValue == null) {
133                        defaultValue = DEFAULT_VALUE.get(parameterType);
134                    }
135    //                if (defaultValue instanceof FactoryBean) {
136    //                    try {
137    //                        defaultValue = ((FactoryBean)defaultValue).getObject();
138    //                    } catch (Exception e) {
139    //                        throw new FatalBeanException("Unable to get object value from bean factory", e);
140    //                    }
141    //                }
142                    MutableValueMetadata valueMetadata = parserContext.createMetadata(MutableValueMetadata.class);
143                    valueMetadata.setStringValue(defaultValue);
144                    valueMetadata.setType(parameterType.getName());
145                    beanMetadata.addArgument(valueMetadata, parameterType.getName(), i);
146                }
147            }
148    
149            // todo set any usable default values on the bean definition
150        }
151    
152        private ConstructionInfo selectConstructionMethod(MutableBeanMetadata beanMetadata, MappingMetaData metadata) {
153            Class beanClass = beanMetadata.getRuntimeClass();
154    
155            // get a set containing the names of the defined properties
156            Set<String> definedProperties = new HashSet<String>();
157            List<BeanProperty> values = beanMetadata.getProperties();
158            for (BeanProperty beanProperty : values) {
159                definedProperties.add(beanProperty.getName());
160            }
161    
162            // first check for a factory method
163            if (beanMetadata.getFactoryMethod() != null) {
164                return selectFactory(beanClass, beanMetadata, metadata, definedProperties);
165            } else {
166                return selectConstructor(beanClass, metadata, definedProperties);
167            }
168        }
169    
170        private ConstructionInfo selectFactory(Class beanClass, MutableBeanMetadata beanMetadata, MappingMetaData metadata, Set definedProperties) {
171            String factoryMethodName = beanMetadata.getFactoryMethod();
172    
173            // get the factory methods sorted by longest arg length first
174            Method[] methods = beanClass.getMethods();
175            List<Method> factoryMethods = new ArrayList<Method>(methods.length);
176            for (Method method : methods) {
177                if (method.getName().equals(factoryMethodName)) {
178                    factoryMethods.add(method);
179                }
180            }
181    
182            Collections.sort(factoryMethods, new MethodArgLengthComparator());
183    
184            // if a factory method has been annotated as the default constructor we always use that constructor
185            for (Method factoryMethod : factoryMethods) {
186                if (metadata.isDefaultFactoryMethod(beanClass, factoryMethod)) {
187                    return new ConstructionInfo(beanClass, factoryMethod, metadata);
188                }
189            }
190    
191            // try to find a constructor for which we have all of the properties defined
192            for (Method factoryMethod : factoryMethods) {
193                ConstructionInfo constructionInfo = new ConstructionInfo(beanClass, factoryMethod, metadata);
194                if (isUsableConstructor(constructionInfo, definedProperties)) {
195                    return constructionInfo;
196                }
197            }
198            return null;
199        }
200    
201        private ConstructionInfo selectConstructor(Class beanClass, MappingMetaData metadata, Set definedProperties) {
202            // get the constructors sorted by longest arg length first
203            List<Constructor> constructors = new ArrayList<Constructor>(Arrays.asList(beanClass.getConstructors()));
204            Collections.sort(constructors, new ConstructorArgLengthComparator());
205    
206            // if a constructor has been annotated as the default constructor we always use that constructor
207            for (Constructor constructor : constructors) {
208                if (metadata.isDefaultConstructor(constructor)) {
209                    return new ConstructionInfo(constructor, metadata);
210                }
211            }
212    
213            // try to find a constructor for which we have all of the properties defined
214            for (Constructor constructor : constructors) {
215                ConstructionInfo constructionInfo = new ConstructionInfo(constructor, metadata);
216                if (isUsableConstructor(constructionInfo, definedProperties)) {
217                    return constructionInfo;
218                }
219            }
220            return null;
221        }
222    
223        private boolean isUsableConstructor(ConstructionInfo constructionInfo, Set definedProperties) {
224            // if we don't have parameter names this is not the constructor we are looking for
225            String[] parameterNames = constructionInfo.parameterNames;
226            if (parameterNames == null) {
227                return false;
228            }
229    
230            Class[] parameterTypes = constructionInfo.parameterTypes;
231            for (int i = 0; i < parameterNames.length; i++) {
232                String parameterName = parameterNames[i];
233                Class parameterType = parameterTypes[i];
234    
235                // can we satify this property using a defined property or default property
236                if (!definedProperties.contains(parameterName) && !defaultValues.containsKey(new PropertyKey(parameterName, parameterType))) {
237                    return false;
238                }
239            }
240    
241            return true;
242        }
243    
244        private class ConstructionInfo {
245            private final Class[] parameterTypes;
246            private final String[] parameterNames;
247    
248            public ConstructionInfo(Constructor constructor, MappingMetaData metadata) {
249                this.parameterTypes = constructor.getParameterTypes();
250                String[] names = metadata.getParameterNames(constructor);
251    
252                // verify that we have enough parameter names
253                int expectedParameterCount = parameterTypes.length;
254                if (names != null && names.length != expectedParameterCount) {
255                    throw new ComponentDefinitionException("Excpected " + expectedParameterCount + " parameter names for constructor but only got " +
256                            names.length + ": " + constructor.toString());
257                }
258                if (expectedParameterCount == 0) {
259                    names = new String[0];
260                }
261    
262                this.parameterNames = names;
263            }
264    
265            public ConstructionInfo(Class beanClass, Method factoryMethod, MappingMetaData metadata) {
266                this.parameterTypes = factoryMethod.getParameterTypes();
267    
268                String[] names = metadata.getParameterNames(beanClass, factoryMethod);
269    
270                // verify that we have enough parameter names
271                int expectedParameterCount = parameterTypes.length;
272                if (names != null && names.length != expectedParameterCount) {
273                    throw new ComponentDefinitionException("Excpected " + expectedParameterCount + " parameter names for factory method but only got " +
274                            names.length + ": " + factoryMethod.toString());
275                }
276                if (expectedParameterCount == 0) {
277                    names = new String[0];
278                }
279    
280                this.parameterNames = names;
281            }
282        }
283    
284        private static class MethodArgLengthComparator implements Comparator<Method> {
285            public int compare(Method o1, Method o2) {
286                return getArgLength(o2) - getArgLength(o1);
287            }
288    
289            private int getArgLength(Method object) {
290                return object.getParameterTypes().length;
291            }
292        }
293        
294        private static class ConstructorArgLengthComparator implements Comparator<Constructor> {
295            public int compare(Constructor o1, Constructor o2) {
296                return getArgLength(o2) - getArgLength(o1);
297            }
298    
299            private int getArgLength(Constructor object) {
300                return object.getParameterTypes().length;
301            }
302        }
303    
304        private static class PropertyKey {
305            private final String name;
306            private final Class type;
307    
308            public PropertyKey(String name, Class type) {
309                this.name = name;
310                this.type = type;
311            }
312    
313            public boolean equals(Object object) {
314                if (!(object instanceof PropertyKey)) {
315                    return false;
316                }
317    
318                PropertyKey defaultProperty = (PropertyKey) object;
319                return name.equals(defaultProperty.name) && type.equals(type);
320            }
321    
322            public int hashCode() {
323                int result = 17;
324                result = 37 * result + name.hashCode();
325                result = 37 * result + type.hashCode();
326                return result;
327            }
328    
329            public String toString() {
330                return "[" + name + " " + type + "]";
331            }
332        }
333    
334        private static final Map<Class, String> DEFAULT_VALUE;
335    
336        static {
337            Map<Class, String> temp = new HashMap<Class, String>();
338            temp.put(Boolean.TYPE, Boolean.FALSE.toString());
339            temp.put(Byte.TYPE, "0B");
340            temp.put(Character.TYPE, "\\u000");
341            temp.put(Short.TYPE, "0S");
342            temp.put(Integer.TYPE, "0");
343            temp.put(Long.TYPE, "0L");
344            temp.put(Float.TYPE, "0F");
345            temp.put(Double.TYPE, "0D");
346    
347            DEFAULT_VALUE = Collections.unmodifiableMap(temp);
348        }
349    }