content: /*
   * Copyright 2010-2025 Hyland Software, Inc. and its affiliates.
   *
   * Licensed 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.activiti.core.el;
  
  import com.fasterxml.jackson.databind.JsonNode;
  import com.fasterxml.jackson.databind.ObjectMapper;
  import com.fasterxml.jackson.databind.node.ObjectNode;
  import jakarta.el.CompositeELResolver;
  import jakarta.el.ELContext;
  import jakarta.el.ELException;
  import jakarta.el.ELResolver;
  import jakarta.el.PropertyNotWritableException;
  import java.beans.FeatureDescriptor;
  import java.math.BigDecimal;
  import java.util.Iterator;
  import java.util.List;
  
  /**
   * Defines property resolution behavior on JsonNodes.
   *
   * @see CompositeELResolver
   * @see ELResolver
   */
  public class JsonNodeELResolver extends ELResolver {
  
      private final boolean readOnly;
      private final ObjectMapper defaultObjectMapper = new ObjectMapper();
  
      /**
       * Creates a new read/write BeanELResolver.
       */
      public JsonNodeELResolver() {
          this(false);
      }
  
      /**
       * Creates a new BeanELResolver whose read-only status is determined by the
       * given parameter.
       */
      public JsonNodeELResolver(boolean readOnly) {
          this.readOnly = readOnly;
      }
  
      /**
       * If the base object is not null, returns the most general type that this
       * resolver accepts for the property argument. Otherwise, returns null.
       * Assuming the base is not null, this method will always return
       * Object.class. This is because any object is accepted as a key and is
       * coerced into a string.
       *
       * @param context
       *            The context of this evaluation.
       * @param base
       *            The bean to analyze.
       * @return null if base is null; otherwise Object.class.
       */
      @Override
      public Class<?> getCommonPropertyType(ELContext context, Object base) {
          return isResolvable(base) ? Object.class : null;
      }
  
      /**
       * If the base object is not null, returns an Iterator containing the set of
       * JavaBeans properties available on the given object. Otherwise, returns
       * null. The Iterator returned must contain zero or more instances of
       * java.beans.FeatureDescriptor. Each info object contains information about
       * a property in the bean, as obtained by calling the
       * BeanInfo.getPropertyDescriptors method. The FeatureDescriptor is
       * initialized using the same fields as are present in the
       * PropertyDescriptor, with the additional required named attributes "type"
       * and "resolvableAtDesignTime" set as follows:
       * <ul>
       * <li>{@link ELResolver#TYPE} - The runtime type of the property, from
       * PropertyDescriptor.getPropertyType().</li>
       * <li>{@link ELResolver#RESOLVABLE_AT_DESIGN_TIME} - true.</li>
       * </ul>
       *
       * @param context
       *            The context of this evaluation.
       * @param base
       *            The bean to analyze.
       * @return An Iterator containing zero or more FeatureDescriptor objects,
       *         each representing a property on this bean, or null if the base
       *         object is null.
       */
      @Override
      public Iterator<FeatureDescriptor> getFeatureDescriptors(ELContext context, Object base) {
          if (isResolvable(base)) {
              JsonNode node = (JsonNode) base;
              final Iterator<String> keys = node.fieldNames();
              return new Iterator<FeatureDescriptor>() {
                  @Override
                  public boolean hasNext() {
                      return keys.hasNext();
                  }
  
                  @Override
                  public FeatureDescriptor next() {
                      Object key = keys.next();
                      FeatureDescriptor feature = new FeatureDescriptor();
                      feature.setDisplayName(key == null ? "null" : key.toString());
                      feature.setName(feature.getDisplayName());
                      feature.setShortDescription("");
                      feature.setExpert(true);
                      feature.setHidden(false);
                      feature.setPreferred(true);
                      feature.setValue(TYPE, key == null ? "null" : key.getClass());
                      feature.setValue(RESOLVABLE_AT_DESIGN_TIME, true);
                      return feature;
                  }
  
                  @Override
                  public void remove() {
                      throw new UnsupportedOperationException("cannot remove");
                  }
              };
          }
          return null;
      }
  
      /**
       * If the base object is a map, returns the most general acceptable type for
       * a value in this map. If the base is a Map, the propertyResolved property
       * of the ELContext object must be set to true by this resolver, before
       * returning. If this property is not true after this method is called, the
       * caller should ignore the return value. Assuming the base is a Map, this
       * method will always return Object.class. This is because Maps accept any
       * object as the value for a given key.
       *
       * @param context
       *            The context of this evaluation.
       * @param base
       *            The map to analyze. Only bases of type Map are handled by this
       *            resolver.
       * @param property
       *            The key to return the acceptable type for. Ignored by this
       *            resolver.
       * @return If the propertyResolved property of ELContext was set to true,
       *         then the most general acceptable type; otherwise undefined.
       * @throws NullPointerException
       *             if context is null
       * @throws ELException
       *             if an exception was thrown while performing the property or
       *             variable resolution. The thrown exception must be included as
       *             the cause property of this exception, if available.
       */
      @Override
      public Class<?> getType(ELContext context, Object base, Object property) {
          if (context == null) {
              throw new NullPointerException("context is null");
          }
          Class<?> result = null;
          if (isResolvable(base)) {
              result = Object.class;
              context.setPropertyResolved(true);
          }
          return result;
      }
  
      /**
       * If the base object is a map, returns the value associated with the given
       * key, as specified by the property argument. If the key was not found,
       * null is returned. If the base is a Map, the propertyResolved property of
       * the ELContext object must be set to true by this resolver, before
       * returning. If this property is not true after this method is called, the
       * caller should ignore the return value. Just as in
       * java.util.Map.get(Object), just because null is returned doesn't mean
       * there is no mapping for the key; it's also possible that the Map
       * explicitly maps the key to null.
       *
       * @param context
       *            The context of this evaluation.
       * @param base
       *            The map to analyze. Only bases of type Map are handled by this
       *            resolver.
       * @param property
       *            The key to return the acceptable type for. Ignored by this
       *            resolver.
       * @return If the propertyResolved property of ELContext was set to true,
       *         then the value associated with the given key or null if the key
       *         was not found. Otherwise, undefined.
       * @throws ClassCastException
       *             if the key is of an inappropriate type for this map
       *             (optionally thrown by the underlying Map).
       * @throws NullPointerException
       *             if context is null, or if the key is null and this map does
       *             not permit null keys (the latter is optionally thrown by the
       *             underlying Map).
       * @throws ELException
       *             if an exception was thrown while performing the property or
       *             variable resolution. The thrown exception must be included as
       *             the cause property of this exception, if available.
       */
      @Override
      public Object getValue(ELContext context, Object base, Object property) {
          if (context == null) {
              throw new NullPointerException("context is null");
          }
          Object result = null;
          if (isResolvable(base)) {
              JsonNode resultNode = ((JsonNode) base).get(property.toString());
              if (resultNode != null && resultNode.isValueNode()) {
                  if (resultNode.isBoolean()) {
                      result = resultNode.asBoolean();
                  } else if (resultNode.isLong()) {
                      result = resultNode.asLong();
                  } else if (resultNode.isBigDecimal() || resultNode.isDouble()) {
                      result = resultNode.asDouble();
                  } else if (resultNode.isTextual()) {
                      result = resultNode.asText();
                  } else {
                      result = resultNode.toString();
                  }
              } else {
                  if (resultNode.isArray()) {
                      result = getObjectMapper().convertValue(resultNode, List.class);
                  } else {
                      result = resultNode;
                  }
              }
              context.setPropertyResolved(true);
          }
          return result;
      }
  
      /**
       * Returns the {@link ObjectMapper} used internally to convert {@link List}
       * properties. Subclasses may override this method to provide a specific one
       */
      protected ObjectMapper getObjectMapper() {
          return defaultObjectMapper;
      }
  
      /**
       * If the base object is a map, returns whether a call to
       * {@link #setValue(ELContext, Object, Object, Object)} will always fail. If
       * the base is a Map, the propertyResolved property of the ELContext object
       * must be set to true by this resolver, before returning. If this property
       * is not true after this method is called, the caller should ignore the
       * return value. If this resolver was constructed in read-only mode, this
       * method will always return true. If a Map was created using
       * java.util.Collections.unmodifiableMap(Map), this method must return true.
       * Unfortunately, there is no Collections API method to detect this.
       * However, an implementation can create a prototype unmodifiable Map and
       * query its runtime type to see if it matches the runtime type of the base
       * object as a workaround.
       *
       * @param context
       *            The context of this evaluation.
       * @param base
       *            The map to analyze. Only bases of type Map are handled by this
       *            resolver.
       * @param property
       *            The key to return the acceptable type for. Ignored by this
       *            resolver.
       * @return If the propertyResolved property of ELContext was set to true,
       *         then true if calling the setValue method will always fail or
       *         false if it is possible that such a call may succeed; otherwise
       *         undefined.
       * @throws NullPointerException
       *             if context is null.
       * @throws ELException
       *             if an exception was thrown while performing the property or
       *             variable resolution. The thrown exception must be included as
       *             the cause property of this exception, if available.
       */
      @Override
      public boolean isReadOnly(ELContext context, Object base, Object property) {
          if (context == null) {
              throw new NullPointerException("context is null");
          }
          if (isResolvable(base)) {
              context.setPropertyResolved(true);
          }
          return readOnly;
      }
  
      /**
       * If the base object is a map, attempts to set the value associated with
       * the given key, as specified by the property argument. If the base is a
       * Map, the propertyResolved property of the ELContext object must be set to
       * true by this resolver, before returning. If this property is not true
       * after this method is called, the caller can safely assume no value was
       * set. If this resolver was constructed in read-only mode, this method will
       * always throw PropertyNotWritableException. If a Map was created using
       * java.util.Collections.unmodifiableMap(Map), this method must throw
       * PropertyNotWritableException. Unfortunately, there is no Collections API
       * method to detect this. However, an implementation can create a prototype
       * unmodifiable Map and query its runtime type to see if it matches the
       * runtime type of the base object as a workaround.
       *
       * @param context
       *            The context of this evaluation.
       * @param base
       *            The map to analyze. Only bases of type Map are handled by this
       *            resolver.
       * @param property
       *            The key to return the acceptable type for. Ignored by this
       *            resolver.
       * @param value
       *            The value to be associated with the specified key.
       * @throws ClassCastException
       *             if the class of the specified key or value prevents it from
       *             being stored in this map.
       * @throws NullPointerException
       *             if context is null, or if this map does not permit null keys
       *             or values, and the specified key or value is null.
       * @throws IllegalArgumentException
       *             if some aspect of this key or value prevents it from being
       *             stored in this map.
       * @throws PropertyNotWritableException
       *             if this resolver was constructed in read-only mode, or if the
       *             put operation is not supported by the underlying map.
       * @throws ELException
       *             if an exception was thrown while performing the property or
       *             variable resolution. The thrown exception must be included as
       *             the cause property of this exception, if available.
       */
      @Override
      public void setValue(ELContext context, Object base, Object property, Object value) {
          if (context == null) {
              throw new NullPointerException("context is null");
          }
          if (base instanceof ObjectNode node) {
              if (readOnly) {
                  throw new PropertyNotWritableException("resolver is read-only");
              }
              if (value instanceof BigDecimal decimal) {
                  node.put(property.toString(), decimal);
              } else if (value instanceof Boolean booleanValue) {
                  node.put(property.toString(), booleanValue);
              } else if (value instanceof Long longValue) {
                  node.put(property.toString(), longValue);
              } else if (value instanceof Double doubleValue) {
                  node.put(property.toString(), doubleValue);
              } else if (value != null) {
                  node.put(property.toString(), value.toString());
              } else {
                  node.putNull(property.toString());
              }
              context.setPropertyResolved(true);
          }
      }
  
      /**
       * Test whether the given base should be resolved by this ELResolver.
       */
      private final boolean isResolvable(Object base) {
          return base instanceof JsonNode;
      }
  }
  