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

   1 /*
   2  * Copyright (C) 2010 Mathieu Baudier <mbaudier@argeo.org>
   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
  17 package org.argeo.slc.core.execution;
  18
  19 import java.beans.PropertyDescriptor;
  20 import java.util.HashSet;
  21 import java.util.Iterator;
  22 import java.util.List;
  23 import java.util.Map;
  24 import java.util.Set;
  25
  26 import org.apache.commons.logging.Log;
  27 import org.apache.commons.logging.LogFactory;
  28 import org.argeo.slc.SlcException;
  29 import org.argeo.slc.execution.ExecutionContext;
  30 import org.argeo.slc.execution.ExecutionFlow;
  31 import org.springframework.beans.BeansException;
  32 import org.springframework.beans.MutablePropertyValues;
  33 import org.springframework.beans.PropertyValue;
  34 import org.springframework.beans.PropertyValues;
  35 import org.springframework.beans.factory.BeanDefinitionStoreException;
  36 import org.springframework.beans.factory.config.InstantiationAwareBeanPostProcessorAdapter;
  37 import org.springframework.beans.factory.config.TypedStringValue;
  38 import org.springframework.beans.factory.support.ManagedList;
  39 import org.springframework.beans.factory.support.ManagedMap;
  40 import org.springframework.beans.factory.support.ManagedSet;
  41 import org.springframework.util.ObjectUtils;
  42 import org.springframework.util.StringUtils;
  43
  44 /**
  45  * Spring post processor which ensures that execution parameters are properly
  46  * set. It is used at two levels: first during instantiation for instantiation
  47  * parameters which allow to implement templates, then at runtime in order to
  48  * interpret @{} placeholders when object of scope execution are instantiated.
  49  */
  50 public class ExecutionParameterPostProcessor extends
  51                 InstantiationAwareBeanPostProcessorAdapter {
  52
  53         private final static Log log = LogFactory
  54                         .getLog(ExecutionParameterPostProcessor.class);
  55
  56         private ExecutionContext executionContext;
  57         private InstantiationManager instantiationManager;
  58
  59         private String placeholderPrefix = "@{";
  60         private String placeholderSuffix = "}";
  61         private String nullValue;
  62
  63         @Override
  64         public PropertyValues postProcessPropertyValues(PropertyValues pvs,
  65                         PropertyDescriptor[] pds, Object bean, String beanName)
  66                         throws BeansException {
  67
  68                 // TODO: resolve at execution only if scope is execution
  69                 // TODO: deal with placeholders in RuntimeBeanReference and
  70                 // RuntimeBeanNameReference
  71
  72                 MutablePropertyValues newPvs = new MutablePropertyValues();
  73
  74                 boolean changesOccured = false;
  75
  76                 for (PropertyValue pv : pvs.getPropertyValues()) {
  77                         Object convertedValue = resolveValue(beanName, bean, pv.getValue());
  78                         newPvs.addPropertyValue(new PropertyValue(pv, convertedValue));
  79                         if (convertedValue != pv.getValue()) {
  80                                 changesOccured = true;
  81                         }
  82                 }
  83
  84                 return changesOccured ? newPvs : pvs;
  85         }
  86
  87         @Override
  88         public boolean postProcessAfterInstantiation(Object bean, String beanName)
  89                         throws BeansException {
  90                 if (bean instanceof ExecutionFlow)
  91                         instantiationManager.flowInitializationStarted(
  92                                         (ExecutionFlow) bean, beanName);
  93                 return true;
  94         }
  95
  96         @Override
  97         public Object postProcessAfterInitialization(Object bean, String beanName)
  98                         throws BeansException {
  99                 if (bean instanceof ExecutionFlow)
 100                         instantiationManager.flowInitializationFinished(
 101                                         (ExecutionFlow) bean, beanName);
 102                 return bean;
 103         }
 104
 105         protected String resolvePlaceholder(Object bean, String placeholder) {
 106                 if (instantiationManager.isInFlowInitialization())
 107                         return instantiationManager.getInitializingFlowParameter(
 108                                         placeholder).toString();
 109
 110                 else {// execution
 111                                 // next call fail if no execution context available
 112                         Object obj = executionContext.getVariable(placeholder);
 113                         if (obj != null) {
 114                                 return obj.toString();
 115                         }
 116                 }
 117
 118                 return null;
 119         }
 120
 121         @SuppressWarnings(value = { "unchecked" })
 122         public Object resolveValue(String beanName, Object bean, Object value) {
 123                 if (value instanceof TypedStringValue) {
 124                         TypedStringValue tsv = (TypedStringValue) value;
 125                         String originalValue = tsv.getValue();
 126
 127                         String convertedValue = resolveString(beanName, bean, originalValue);
 128                         if (convertedValue == null)
 129                                 return null;
 130                         return convertedValue.equals(originalValue) ? value
 131                                         : new TypedStringValue(convertedValue);
 132                 } else if (value instanceof String) {
 133                         String originalValue = value.toString();
 134                         String convertedValue = resolveString(beanName, bean, originalValue);
 135                         if (convertedValue == null)
 136                                 return null;
 137                         return convertedValue.equals(originalValue) ? value
 138                                         : convertedValue;
 139                 } else if (value instanceof ManagedMap) {
 140                         Map<?, ?> mapVal = (Map<?, ?>) value;
 141
 142                         Map<Object, Object> newContent = new ManagedMap();
 143                         boolean entriesModified = false;
 144                         for (Iterator<?> it = mapVal.entrySet().iterator(); it.hasNext();) {
 145                                 Map.Entry<?, ?> entry = (Map.Entry<?, ?>) it.next();
 146                                 Object key = entry.getKey();
 147                                 int keyHash = (key != null ? key.hashCode() : 0);
 148                                 Object newKey = resolveValue(beanName, bean, key);
 149                                 int newKeyHash = (newKey != null ? newKey.hashCode() : 0);
 150                                 Object val = entry.getValue();
 151                                 Object newVal = resolveValue(beanName, bean, val);
 152                                 newContent.put(newKey, newVal);
 153                                 entriesModified = entriesModified
 154                                                 || (newVal != val || newKey != key || newKeyHash != keyHash);
 155                         }
 156
 157                         return entriesModified ? newContent : value;
 158                 } else if (value instanceof ManagedList) {
 159                         List<?> listVal = (List<?>) value;
 160                         List<Object> newContent = new ManagedList();
 161                         boolean valueModified = false;
 162
 163                         for (int i = 0; i < listVal.size(); i++) {
 164                                 Object elem = listVal.get(i);
 165                                 Object newVal = resolveValue(beanName, bean, elem);
 166                                 newContent.add(newVal);
 167                                 if (!ObjectUtils.nullSafeEquals(newVal, elem)) {
 168                                         valueModified = true;
 169                                 }
 170                         }
 171                         return valueModified ? newContent : value;
 172                 } else if (value instanceof ManagedSet) {
 173                         Set<?> setVal = (Set<?>) value;
 174                         Set<Object> newContent = new ManagedSet();
 175                         boolean entriesModified = false;
 176                         for (Iterator<?> it = setVal.iterator(); it.hasNext();) {
 177                                 Object elem = it.next();
 178                                 int elemHash = (elem != null ? elem.hashCode() : 0);
 179                                 Object newVal = resolveValue(beanName, bean, elem);
 180                                 int newValHash = (newVal != null ? newVal.hashCode() : 0);
 181                                 newContent.add(newVal);
 182                                 entriesModified = entriesModified
 183                                                 || (newVal != elem || newValHash != elemHash);
 184                         }
 185                         return entriesModified ? newContent : value;
 186                 } else {
 187                         // log.debug(beanName + ": " + value.getClass() + " : " + value);
 188                         return value;
 189                 }
 190
 191         }
 192
 193         private String resolveString(String beanName, Object bean, String strVal) {
 194                 // in case <null/> is passed
 195                 if (strVal == null)
 196                         return null;
 197
 198                 String value = parseStringValue(bean, strVal, new HashSet<String>());
 199
 200                 if (value == null)
 201                         throw new SlcException("Could not resolve placeholder '" + strVal
 202                                         + "' in bean '" + beanName + "'");
 203
 204                 return (value.equals(nullValue) ? null : value);
 205         }
 206
 207         public void setPlaceholderPrefix(String placeholderPrefix) {
 208                 this.placeholderPrefix = placeholderPrefix;
 209         }
 210
 211         public void setPlaceholderSuffix(String placeholderSuffix) {
 212                 this.placeholderSuffix = placeholderSuffix;
 213         }
 214
 215         public void setNullValue(String nullValue) {
 216                 this.nullValue = nullValue;
 217         }
 218
 219         public void setInstantiationManager(
 220                         InstantiationManager instantiationManager) {
 221                 this.instantiationManager = instantiationManager;
 222         }
 223
 224         public void setExecutionContext(ExecutionContext executionContext) {
 225                 this.executionContext = executionContext;
 226         }
 227
 228         //
 229         // Following methods hacked from the internals of
 230         // PropertyPlaceholderConfigurer
 231         //
 232
 233         protected String parseStringValue(Object bean, String strVal,
 234                         Set<String> visitedPlaceholders)
 235                         throws BeanDefinitionStoreException {
 236
 237                 // in case <null/> is passed
 238                 if (strVal == null)
 239                         return null;
 240
 241                 StringBuffer buf = new StringBuffer(strVal);
 242
 243                 int startIndex = strVal.indexOf(placeholderPrefix);
 244                 while (startIndex != -1) {
 245                         int endIndex = findPlaceholderEndIndex(buf, startIndex);
 246                         if (endIndex != -1) {
 247                                 String placeholder = buf.substring(startIndex
 248                                                 + placeholderPrefix.length(), endIndex);
 249                                 if (!visitedPlaceholders.add(placeholder)) {
 250                                         throw new BeanDefinitionStoreException(
 251                                                         "Circular placeholder reference '" + placeholder
 252                                                                         + "' in property definitions");
 253                                 }
 254                                 // Recursive invocation, parsing placeholders contained in
 255                                 // the placeholder key.
 256                                 placeholder = parseStringValue(bean, placeholder,
 257                                                 visitedPlaceholders);
 258                                 // Now obtain the value for the fully resolved key...
 259                                 String propVal = resolvePlaceholder(bean, placeholder);
 260                                 if (propVal != null) {
 261                                         // Recursive invocation, parsing placeholders contained
 262                                         // in the
 263                                         // previously resolved placeholder value.
 264                                         propVal = parseStringValue(bean, propVal,
 265                                                         visitedPlaceholders);
 266                                         buf.replace(startIndex,
 267                                                         endIndex + placeholderSuffix.length(), propVal);
 268                                         if (log.isTraceEnabled()) {
 269                                                 log.trace("Resolved placeholder '" + placeholder + "'");
 270                                         }
 271                                         startIndex = buf.indexOf(placeholderPrefix, startIndex
 272                                                         + propVal.length());
 273                                 } else {
 274                                         throw new BeanDefinitionStoreException(
 275                                                         "Could not resolve placeholder '" + placeholder
 276                                                                         + "'");
 277                                 }
 278                                 visitedPlaceholders.remove(placeholder);
 279                         } else {
 280                                 startIndex = -1;
 281                         }
 282                 }
 283
 284                 return buf.toString();
 285         }
 286
 287         private int findPlaceholderEndIndex(CharSequence buf, int startIndex) {
 288                 int index = startIndex + placeholderPrefix.length();
 289                 int withinNestedPlaceholder = 0;
 290                 while (index < buf.length()) {
 291                         if (StringUtils.substringMatch(buf, index, placeholderSuffix)) {
 292                                 if (withinNestedPlaceholder > 0) {
 293                                         withinNestedPlaceholder--;
 294                                         index = index + placeholderSuffix.length();
 295                                 } else {
 296                                         return index;
 297                                 }
 298                         } else if (StringUtils
 299                                         .substringMatch(buf, index, placeholderPrefix)) {
 300                                 withinNestedPlaceholder++;
 301                                 index = index + placeholderPrefix.length();
 302                         } else {
 303                                 index++;
 304                         }
 305                 }
 306                 return -1;
 307         }
 308
 309 }