org.argeo.slc.core/src/org/argeo/slc/core/execution/ExecutionParameterPostProcessor.java

   1 /*
   2  * Copyright (C) 2007-2012 Argeo GmbH
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License");
   5  * you may not use this file except in compliance with the License.
   6  * You may obtain a copy of the License at
   7  *
   8  *         http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  */
  16 package org.argeo.slc.core.execution;
  17
  18 import java.beans.PropertyDescriptor;
  19 import java.util.HashSet;
  20 import java.util.Iterator;
  21 import java.util.List;
  22 import java.util.Map;
  23 import java.util.Set;
  24
  25 import org.apache.commons.logging.Log;
  26 import org.apache.commons.logging.LogFactory;
  27 import org.argeo.slc.SlcException;
  28 import org.argeo.slc.execution.ExecutionContext;
  29 import org.argeo.slc.execution.ExecutionFlow;
  30 import org.springframework.beans.BeansException;
  31 import org.springframework.beans.MutablePropertyValues;
  32 import org.springframework.beans.PropertyValue;
  33 import org.springframework.beans.PropertyValues;
  34 import org.springframework.beans.factory.BeanDefinitionStoreException;
  35 import org.springframework.beans.factory.config.InstantiationAwareBeanPostProcessorAdapter;
  36 import org.springframework.beans.factory.config.TypedStringValue;
  37 import org.springframework.beans.factory.support.ManagedList;
  38 import org.springframework.beans.factory.support.ManagedMap;
  39 import org.springframework.beans.factory.support.ManagedSet;
  40 import org.springframework.util.ObjectUtils;
  41 import org.springframework.util.StringUtils;
  42
  43 /**
  44  * Spring post processor which ensures that execution parameters are properly
  45  * set. It is used at two levels: first during instantiation for instantiation
  46  * parameters which allow to implement templates, then at runtime in order to
  47  * interpret @{} placeholders when object of scope execution are instantiated.
  48  */
  49 public class ExecutionParameterPostProcessor extends
  50                 InstantiationAwareBeanPostProcessorAdapter {
  51
  52         private final static Log log = LogFactory
  53                         .getLog(ExecutionParameterPostProcessor.class);
  54
  55         private ExecutionContext executionContext;
  56         private InstantiationManager instantiationManager;
  57
  58         private String placeholderPrefix = "@{";
  59         private String placeholderSuffix = "}";
  60         private String nullValue;
  61
  62         @Override
  63         public PropertyValues postProcessPropertyValues(PropertyValues pvs,
  64                         PropertyDescriptor[] pds, Object bean, String beanName)
  65                         throws BeansException {
  66
  67                 // TODO: resolve at execution only if scope is execution
  68                 // TODO: deal with placeholders in RuntimeBeanReference and
  69                 // RuntimeBeanNameReference
  70
  71                 MutablePropertyValues newPvs = new MutablePropertyValues();
  72
  73                 boolean changesOccured = false;
  74
  75                 for (PropertyValue pv : pvs.getPropertyValues()) {
  76                         Object convertedValue = resolveValue(beanName, bean, pv.getValue());
  77                         newPvs.addPropertyValue(new PropertyValue(pv, convertedValue));
  78                         if (convertedValue != pv.getValue()) {
  79                                 changesOccured = true;
  80                         }
  81                 }
  82
  83                 return changesOccured ? newPvs : pvs;
  84         }
  85
  86         @Override
  87         public boolean postProcessAfterInstantiation(Object bean, String beanName)
  88                         throws BeansException {
  89                 if (bean instanceof ExecutionFlow)
  90                         instantiationManager.flowInitializationStarted(
  91                                         (ExecutionFlow) bean, beanName);
  92                 return true;
  93         }
  94
  95         @Override
  96         public Object postProcessAfterInitialization(Object bean, String beanName)
  97                         throws BeansException {
  98                 if (bean instanceof ExecutionFlow)
  99                         instantiationManager.flowInitializationFinished(
 100                                         (ExecutionFlow) bean, beanName);
 101                 return bean;
 102         }
 103
 104         protected String resolvePlaceholder(Object bean, String placeholder) {
 105                 if (instantiationManager.isInFlowInitialization())
 106                         return instantiationManager.getInitializingFlowParameter(
 107                                         placeholder).toString();
 108
 109                 else {// execution
 110                                 // next call fail if no execution context available
 111                         Object obj = executionContext.getVariable(placeholder);
 112                         if (obj != null) {
 113                                 return obj.toString();
 114                         }
 115                 }
 116
 117                 return null;
 118         }
 119
 120         public Object resolveValue(String beanName, Object bean, Object value) {
 121                 if (value instanceof TypedStringValue) {
 122                         TypedStringValue tsv = (TypedStringValue) value;
 123                         String originalValue = tsv.getValue();
 124
 125                         String convertedValue = resolveString(beanName, bean, originalValue);
 126                         if (convertedValue == null)
 127                                 return null;
 128                         return convertedValue.equals(originalValue) ? value
 129                                         : new TypedStringValue(convertedValue);
 130                 } else if (value instanceof String) {
 131                         String originalValue = value.toString();
 132                         String convertedValue = resolveString(beanName, bean, originalValue);
 133                         if (convertedValue == null)
 134                                 return null;
 135                         return convertedValue.equals(originalValue) ? value
 136                                         : convertedValue;
 137                 } else if (value instanceof ManagedMap) {
 138                         Map<?, ?> mapVal = (Map<?, ?>) value;
 139
 140                         Map<Object, Object> newContent = new ManagedMap<Object, Object>();
 141                         boolean entriesModified = false;
 142                         for (Iterator<?> it = mapVal.entrySet().iterator(); it.hasNext();) {
 143                                 Map.Entry<?, ?> entry = (Map.Entry<?, ?>) it.next();
 144                                 Object key = entry.getKey();
 145                                 int keyHash = (key != null ? key.hashCode() : 0);
 146                                 Object newKey = resolveValue(beanName, bean, key);
 147                                 int newKeyHash = (newKey != null ? newKey.hashCode() : 0);
 148                                 Object val = entry.getValue();
 149                                 Object newVal = resolveValue(beanName, bean, val);
 150                                 newContent.put(newKey, newVal);
 151                                 entriesModified = entriesModified
 152                                                 || (newVal != val || newKey != key || newKeyHash != keyHash);
 153                         }
 154
 155                         return entriesModified ? newContent : value;
 156                 } else if (value instanceof ManagedList) {
 157                         List<?> listVal = (List<?>) value;
 158                         List<Object> newContent = new ManagedList<Object>();
 159                         boolean valueModified = false;
 160
 161                         for (int i = 0; i < listVal.size(); i++) {
 162                                 Object elem = listVal.get(i);
 163                                 Object newVal = resolveValue(beanName, bean, elem);
 164                                 newContent.add(newVal);
 165                                 if (!ObjectUtils.nullSafeEquals(newVal, elem)) {
 166                                         valueModified = true;
 167                                 }
 168                         }
 169                         return valueModified ? newContent : value;
 170                 } else if (value instanceof ManagedSet) {
 171                         Set<?> setVal = (Set<?>) value;
 172                         Set<Object> newContent = new ManagedSet<Object>();
 173                         boolean entriesModified = false;
 174                         for (Iterator<?> it = setVal.iterator(); it.hasNext();) {
 175                                 Object elem = it.next();
 176                                 int elemHash = (elem != null ? elem.hashCode() : 0);
 177                                 Object newVal = resolveValue(beanName, bean, elem);
 178                                 int newValHash = (newVal != null ? newVal.hashCode() : 0);
 179                                 newContent.add(newVal);
 180                                 entriesModified = entriesModified
 181                                                 || (newVal != elem || newValHash != elemHash);
 182                         }
 183                         return entriesModified ? newContent : value;
 184                 } else {
 185                         // log.debug(beanName + ": " + value.getClass() + " : " + value);
 186                         return value;
 187                 }
 188
 189         }
 190
 191         private String resolveString(String beanName, Object bean, String strVal) {
 192                 // in case <null/> is passed
 193                 if (strVal == null)
 194                         return null;
 195
 196                 String value = parseStringValue(bean, strVal, new HashSet<String>());
 197
 198                 if (value == null)
 199                         throw new SlcException("Could not resolve placeholder '" + strVal
 200                                         + "' in bean '" + beanName + "'");
 201
 202                 return (value.equals(nullValue) ? null : value);
 203         }
 204
 205         public void setPlaceholderPrefix(String placeholderPrefix) {
 206                 this.placeholderPrefix = placeholderPrefix;
 207         }
 208
 209         public void setPlaceholderSuffix(String placeholderSuffix) {
 210                 this.placeholderSuffix = placeholderSuffix;
 211         }
 212
 213         public void setNullValue(String nullValue) {
 214                 this.nullValue = nullValue;
 215         }
 216
 217         public void setInstantiationManager(
 218                         InstantiationManager instantiationManager) {
 219                 this.instantiationManager = instantiationManager;
 220         }
 221
 222         public void setExecutionContext(ExecutionContext executionContext) {
 223                 this.executionContext = executionContext;
 224         }
 225
 226         //
 227         // Following methods hacked from the internals of
 228         // PropertyPlaceholderConfigurer
 229         //
 230
 231         protected String parseStringValue(Object bean, String strVal,
 232                         Set<String> visitedPlaceholders)
 233                         throws BeanDefinitionStoreException {
 234
 235                 // in case <null/> is passed
 236                 if (strVal == null)
 237                         return null;
 238
 239                 StringBuffer buf = new StringBuffer(strVal);
 240
 241                 int startIndex = strVal.indexOf(placeholderPrefix);
 242                 while (startIndex != -1) {
 243                         int endIndex = findPlaceholderEndIndex(buf, startIndex);
 244                         if (endIndex != -1) {
 245                                 String placeholder = buf.substring(startIndex
 246                                                 + placeholderPrefix.length(), endIndex);
 247                                 if (!visitedPlaceholders.add(placeholder)) {
 248                                         throw new BeanDefinitionStoreException(
 249                                                         "Circular placeholder reference '" + placeholder
 250                                                                         + "' in property definitions");
 251                                 }
 252                                 // Recursive invocation, parsing placeholders contained in
 253                                 // the placeholder key.
 254                                 placeholder = parseStringValue(bean, placeholder,
 255                                                 visitedPlaceholders);
 256                                 // Now obtain the value for the fully resolved key...
 257                                 String propVal = resolvePlaceholder(bean, placeholder);
 258                                 if (propVal != null) {
 259                                         // Recursive invocation, parsing placeholders contained
 260                                         // in the
 261                                         // previously resolved placeholder value.
 262                                         propVal = parseStringValue(bean, propVal,
 263                                                         visitedPlaceholders);
 264                                         buf.replace(startIndex,
 265                                                         endIndex + placeholderSuffix.length(), propVal);
 266                                         if (log.isTraceEnabled()) {
 267                                                 log.trace("Resolved placeholder '" + placeholder + "'");
 268                                         }
 269                                         startIndex = buf.indexOf(placeholderPrefix, startIndex
 270                                                         + propVal.length());
 271                                 } else {
 272                                         throw new BeanDefinitionStoreException(
 273                                                         "Could not resolve placeholder '" + placeholder
 274                                                                         + "'");
 275                                 }
 276                                 visitedPlaceholders.remove(placeholder);
 277                         } else {
 278                                 startIndex = -1;
 279                         }
 280                 }
 281
 282                 return buf.toString();
 283         }
 284
 285         private int findPlaceholderEndIndex(CharSequence buf, int startIndex) {
 286                 int index = startIndex + placeholderPrefix.length();
 287                 int withinNestedPlaceholder = 0;
 288                 while (index < buf.length()) {
 289                         if (StringUtils.substringMatch(buf, index, placeholderSuffix)) {
 290                                 if (withinNestedPlaceholder > 0) {
 291                                         withinNestedPlaceholder--;
 292                                         index = index + placeholderSuffix.length();
 293                                 } else {
 294                                         return index;
 295                                 }
 296                         } else if (StringUtils
 297                                         .substringMatch(buf, index, placeholderPrefix)) {
 298                                 withinNestedPlaceholder++;
 299                                 index = index + placeholderPrefix.length();
 300                         } else {
 301                                 index++;
 302                         }
 303                 }
 304                 return -1;
 305         }
 306
 307 }