All Downloads are FREE. Search and download functionalities are using the official Maven repository.
  • Log In
  • Register

    • com.querydsl.core.util.BeanMap Maven / Gradle / Ivy

    The newest version!
    /*
 *  Copyright 2001-2004 The Apache Software Foundation
 *
 *  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 com.querydsl.core.util;

import java.beans.IntrospectionException;
import java.beans.Introspector;
import java.beans.PropertyDescriptor;
import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.AbstractMap;
import java.util.AbstractSet;
import java.util.ArrayList;
import java.util.Collection;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.function.Function;

/**
 * An implementation of Map for JavaBeans which uses introspection to get and put properties in the
 * bean.
 *
 * 
    If an exception occurs during attempts to get or set a property then the property is
 * considered non existent in the Map
 *
 * 
    
 *
 * @author James Strachan
 * @author Matt Hall, John Watkinson, Stephen Colebourne
 * @version $Revision: 1.1 $ $Date: 2005/10/11 17:05:19 $
 * @since Commons Collections 1.0
 */
@SuppressWarnings("rawtypes")
public class BeanMap extends AbstractMap implements Cloneable {

  private transient Object bean;

  private transient Map readMethods = new HashMap<>();
  private transient Map writeMethods = new HashMap<>();
  private transient Map> types = new HashMap<>();

  /** An empty array. Used to invoke accessors via reflection. */
  private static final Object[] NULL_ARGUMENTS = {};

  /**
   * Maps primitive Class types to transformers. The transformer transform strings into the
   * appropriate primitive wrapper.
   */
  private static final Map, Function> defaultFunctions = new HashMap<>();

  static {
    defaultFunctions.put(
        Boolean.TYPE,
        new Function() {
          @Override
          public Object apply(Object input) {
            return Boolean.valueOf(input.toString());
          }
        });
    defaultFunctions.put(
        Character.TYPE,
        new Function() {
          @Override
          public Object apply(Object input) {
            return input.toString().charAt(0);
          }
        });
    defaultFunctions.put(
        Byte.TYPE,
        new Function() {
          @Override
          public Object apply(Object input) {
            return Byte.valueOf(input.toString());
          }
        });
    defaultFunctions.put(
        Short.TYPE,
        new Function() {
          @Override
          public Object apply(Object input) {
            return Short.valueOf(input.toString());
          }
        });
    defaultFunctions.put(
        Integer.TYPE,
        new Function() {
          @Override
          public Object apply(Object input) {
            return Integer.valueOf(input.toString());
          }
        });
    defaultFunctions.put(
        Long.TYPE,
        new Function() {
          @Override
          public Object apply(Object input) {
            return Long.valueOf(input.toString());
          }
        });
    defaultFunctions.put(
        Float.TYPE,
        new Function() {
          @Override
          public Object apply(Object input) {
            return Float.valueOf(input.toString());
          }
        });
    defaultFunctions.put(
        Double.TYPE,
        new Function() {
          @Override
          public Object apply(Object input) {
            return Double.valueOf(input.toString());
          }
        });
  }

  // Constructors
  // -------------------------------------------------------------------------

  /** Constructs a new empty {@code BeanMap}. */
  public BeanMap() {}

  /**
   * Constructs a new {@code BeanMap} that operates on the specified bean. If the given bean is
   * {@code null}, then this map will be empty.
   *
   * @param bean the bean for this map to operate on
   */
  public BeanMap(Object bean) {
    this.bean = bean;
    initialise();
  }

  // Map interface
  // -------------------------------------------------------------------------

  @Override
  public String toString() {
    return "BeanMap<" + bean + ">";
  }

  /**
   * Clone this bean map using the following process:
   *
   * 
    
   *
   * 
      
   *   
    • If there is no underlying bean, return a cloned BeanMap without a bean.
   *       
      
   *   
    • Since there is an underlying bean, try to instantiate a new bean of the same type using
   *       Class.newInstance().
   *       
      
   *   
    • If the instantiation fails, throw a CloneNotSupportedException
   *       
      
   *   
    • Clone the bean map and set the newly instantiated bean as the underlying bean for the
   *       bean map.
   *       
      
   *   
    • Copy each property that is both readable and writable from the existing object to a
   *       cloned bean map.
   *       
      
   *   
    • If anything fails along the way, throw a CloneNotSupportedException.
   *       
      
   * 
    
   */
  @Override
  public Object clone() throws CloneNotSupportedException {
    var newMap = (BeanMap) super.clone();

    if (bean == null) {
      // no bean, just an empty bean map at the moment.  return a newly
      // cloned and empty bean map.
      return newMap;
    }

    Object newBean = null;
    Class beanClass = null;
    try {
      beanClass = bean.getClass();
      newBean = beanClass.getDeclaredConstructor().newInstance();
    } catch (Exception e) {
      // unable to instantiate
      throw new CloneNotSupportedException(
          "Unable to instantiate the underlying bean \"" + beanClass.getName() + "\": " + e);
    }

    try {
      newMap.setBean(newBean);
    } catch (Exception exception) {
      throw new CloneNotSupportedException(
          "Unable to set bean in the cloned bean map: " + exception);
    }

    try {
      // copy only properties that are readable and writable.  If its
      // not readable, we can't get the value from the old map.  If
      // its not writable, we can't write a value into the new map.
      for (String key : readMethods.keySet()) {
        if (getWriteMethod(key) != null) {
          newMap.put(key, get(key));
        }
      }
    } catch (Exception exception) {
      throw new CloneNotSupportedException(
          "Unable to copy bean values to cloned bean map: " + exception);
    }

    return newMap;
  }

  /**
   * Puts all of the writable properties from the given BeanMap into this BeanMap. Read-only and
   * Write-only properties will be ignored.
   *
   * @param map the BeanMap whose properties to put
   */
  public void putAllWriteable(BeanMap map) {
    for (String key : map.readMethods.keySet()) {
      if (getWriteMethod(key) != null) {
        this.put(key, map.get(key));
      }
    }
  }

  /**
   * This method reinitializes the bean map to have default values for the bean's properties. This
   * is accomplished by constructing a new instance of the bean which the map uses as its underlying
   * data source. This behavior for {@code Map#clear()} differs from the Map contract in that the
   * mappings are not actually removed from the map (the mappings for a BeanMap are fixed).
   */
  @Override
  public void clear() {
    if (bean == null) {
      return;
    }
    Class beanClass = null;
    try {
      beanClass = bean.getClass();
      bean = beanClass.getDeclaredConstructor().newInstance();
    } catch (Exception e) {
      throw new UnsupportedOperationException(
          "Could not create new instance of class: " + beanClass);
    }
  }

  /**
   * Returns true if the bean defines a property with the given name.
   *
   * 
    The given name must be a {@code String}; if not, this method returns false. This method will
   * also return false if the bean does not define a property with that name.
   *
   * 
    Write-only properties will not be matched as the test operates against property read
   * methods.
   *
   * @param name the name of the property to check
   * @return false if the given name is null or is not a {@code String}; false if the bean does not
   *     define a property with that name; or true if the bean does define a property with that name
   */
  public boolean containsKey(String name) {
    var method = getReadMethod(name);
    return method != null;
  }

  /**
   * Returns the value of the bean's property with the given name.
   *
   * 
    The given name must be a {@code String} and must not be null; otherwise, this method returns
   * {@code null}. If the bean defines a property with the given name, the value of that property is
   * returned. Otherwise, {@code null} is returned.
   *
   * 
    Write-only properties will not be matched as the test operates against property read
   * methods.
   *
   * @param name the name of the property whose value to return
   * @return the value of the property with that name
   */
  public Object get(String name) {
    if (bean != null) {
      var method = getReadMethod(name);
      if (method != null) {
        try {
          return method.invoke(bean, NULL_ARGUMENTS);
        } catch (IllegalAccessException
            | NullPointerException
            | InvocationTargetException
            | IllegalArgumentException e) {
        }
      }
    }
    return null;
  }

  /**
   * Sets the bean property with the given name to the given value.
   *
   * @param name the name of the property to set
   * @param value the value to set that property to
   * @return the previous value of that property
   */
  @Override
  public Object put(String name, Object value) {
    if (bean != null) {
      var oldValue = get(name);
      var method = getWriteMethod(name);
      if (method == null) {
        throw new IllegalArgumentException(
            "The bean of type: " + bean.getClass().getName() + " has no property called: " + name);
      }
      try {
        var arguments = createWriteMethodArguments(method, value);
        method.invoke(bean, arguments);

        var newValue = get(name);
        firePropertyChange(name, oldValue, newValue);
      } catch (InvocationTargetException | IllegalAccessException e) {
        throw new IllegalArgumentException(e.getMessage());
      }
      return oldValue;
    }
    return null;
  }

  /**
   * Returns the number of properties defined by the bean.
   *
   * @return the number of properties defined by the bean
   */
  @Override
  public int size() {
    return readMethods.size();
  }

  /**
   * Get the keys for this BeanMap.
   *
   * 
    Write-only properties are not included in the returned set of property names,
   * although it is possible to set their value and to get their type.
   *
   * @return BeanMap keys. The Set returned by this method is not modifiable.
   */
  @Override
  public Set keySet() {
    return readMethods.keySet();
  }

  /**
   * Gets a Set of MapEntry objects that are the mappings for this BeanMap.
   *
   * 
    Each MapEntry can be set but not removed.
   *
   * @return the unmodifiable set of mappings
   */
  @Override
  public Set> entrySet() {
    return new AbstractSet<>() {
      @Override
      public Iterator> iterator() {
        return entryIterator();
      }

      @Override
      public int size() {
        return BeanMap.this.readMethods.size();
      }
    };
  }

  /**
   * Returns the values for the BeanMap.
   *
   * @return values for the BeanMap. The returned collection is not modifiable.
   */
  @Override
  public Collection values() {
    List answer = new ArrayList<>(readMethods.size());
    for (var iter = valueIterator(); iter.hasNext(); ) {
      answer.add(iter.next());
    }
    return answer;
  }

  // Helper methods
  // -------------------------------------------------------------------------

  /**
   * Returns the type of the property with the given name.
   *
   * @param name the name of the property
   * @return the type of the property, or {@code null} if no such property exists
   */
  public Class getType(String name) {
    return types.get(name);
  }

  /**
   * Convenience method for getting an iterator over the keys.
   *
   * 
    Write-only properties will not be returned in the iterator.
   *
   * @return an iterator over the keys
   */
  public Iterator keyIterator() {
    return readMethods.keySet().iterator();
  }

  /**
   * Convenience method for getting an iterator over the values.
   *
   * @return an iterator over the values
   */
  public Iterator valueIterator() {
    final var iter = keyIterator();
    return new Iterator<>() {
      @Override
      public boolean hasNext() {
        return iter.hasNext();
      }

      @Override
      public Object next() {
        Object key = iter.next();
        return get(key);
      }

      @Override
      public void remove() {
        throw new UnsupportedOperationException("remove() not supported for BeanMap");
      }
    };
  }

  /**
   * Convenience method for getting an iterator over the entries.
   *
   * @return an iterator over the entries
   */
  public Iterator> entryIterator() {
    final var iter = keyIterator();
    return new Iterator<>() {
      @Override
      public boolean hasNext() {
        return iter.hasNext();
      }

      @Override
      public Entry next() {
        var key = iter.next();
        var value = get(key);
        return new MyMapEntry(BeanMap.this, key, value);
      }

      @Override
      public void remove() {
        throw new UnsupportedOperationException("remove() not supported for BeanMap");
      }
    };
  }

  // Properties
  // -------------------------------------------------------------------------

  /**
   * Returns the bean currently being operated on. The return value may be null if this map is
   * empty.
   *
   * @return the bean being operated on by this map
   */
  public Object getBean() {
    return bean;
  }

  /**
   * Sets the bean to be operated on by this map. The given value may be null, in which case this
   * map will be empty.
   *
   * @param newBean the new bean to operate on
   */
  public void setBean(Object newBean) {
    bean = newBean;
    reinitialise();
  }

  /**
   * Returns the accessor for the property with the given name.
   *
   * @param name the name of the property
   * @return the accessor method for the property, or null
   */
  public Method getReadMethod(String name) {
    return readMethods.get(name);
  }

  /**
   * Returns the mutator for the property with the given name.
   *
   * @param name the name of the property
   * @return the mutator method for the property, or null
   */
  public Method getWriteMethod(String name) {
    return writeMethods.get(name);
  }

  // Implementation methods
  // -------------------------------------------------------------------------

  /**
   * Reinitializes this bean. Called during {@link #setBean(Object)}. Does introspection to find
   * properties.
   */
  protected void reinitialise() {
    readMethods.clear();
    writeMethods.clear();
    types.clear();
    initialise();
  }

  private void initialise() {
    if (getBean() == null) {
      return;
    }

    Class beanClass = getBean().getClass();
    try {
      // BeanInfo beanInfo = Introspector.getBeanInfo( bean, null );
      var beanInfo = Introspector.getBeanInfo(beanClass);
      var propertyDescriptors = beanInfo.getPropertyDescriptors();
      if (propertyDescriptors != null) {
        for (PropertyDescriptor propertyDescriptor : propertyDescriptors) {
          if (propertyDescriptor != null) {
            var name = propertyDescriptor.getName();
            var readMethod = propertyDescriptor.getReadMethod();
            var writeMethod = propertyDescriptor.getWriteMethod();
            Class aType = propertyDescriptor.getPropertyType();

            if (readMethod != null) {
              readMethods.put(name, readMethod);
            }
            if (writeMethods != null) {
              writeMethods.put(name, writeMethod);
            }
            types.put(name, aType);
          }
        }
      }
    } catch (IntrospectionException e) {

    }
  }

  /**
   * Called during a successful {@link #put(Object,Object)} operation. Default implementation does
   * nothing. Override to be notified of property changes in the bean caused by this map.
   *
   * @param key the name of the property that changed
   * @param oldValue the old value for that property
   * @param newValue the new value for that property
   */
  protected void firePropertyChange(String key, Object oldValue, Object newValue) {}

  // Implementation classes
  // -------------------------------------------------------------------------

  /** Map entry used by {@link BeanMap}. */
  protected static class MyMapEntry implements Map.Entry {
    private final BeanMap owner;

    private String key;

    private Object value;

    /**
     * Constructs a new MyMapEntry.
     *
     * @param owner the BeanMap this entry belongs to
     * @param key the key for this entry
     * @param value the value for this entry
     */
    protected MyMapEntry(BeanMap owner, String key, Object value) {
      this.key = key;
      this.value = value;
      this.owner = owner;
    }

    /**
     * Sets the value.
     *
     * @param value the new value for the entry
     * @return the old value for the entry
     */
    @Override
    public Object setValue(Object value) {
      var key = getKey();
      var oldValue = owner.get(key);

      owner.put(key, value);
      var newValue = owner.get(key);
      this.value = newValue;
      return oldValue;
    }

    @Override
    public String getKey() {
      return key;
    }

    @Override
    public Object getValue() {
      return value;
    }
  }

  /**
   * Creates an array of parameters to pass to the given mutator method. If the given object is not
   * the right type to pass to the method directly, it will be converted using {@link
   * #convertType(Class,Object)}.
   *
   * @param method the mutator method
   * @param value the value to pass to the mutator method
   * @return an array containing one object that is either the given value or a transformed value
   * @throws IllegalAccessException if {@link #convertType(Class,Object)} raises it
   * @throws IllegalArgumentException if any other exception is raised by {@link
   *     #convertType(Class,Object)}
   */
  protected Object[] createWriteMethodArguments(Method method, Object value)
      throws IllegalAccessException {
    try {
      if (value != null) {
        var types = method.getParameterTypes();
        if (types != null && types.length > 0) {
          Class paramType = types[0];
          if (paramType.isPrimitive()) {
            paramType = PrimitiveUtils.wrap(paramType);
          }
          if (!paramType.isAssignableFrom(value.getClass())) {
            value = convertType(paramType, value);
          }
        }
      }
      return new Object[] {value};
    } catch (InvocationTargetException | InstantiationException e) {
      throw new IllegalArgumentException(e.getMessage());
    }
  }

  /**
   * Converts the given value to the given type. First, reflection is is used to find a public
   * constructor declared by the given class that takes one argument, which must be the precise type
   * of the given value. If such a constructor is found, a new object is created by passing the
   * given value to that constructor, and the newly constructed object is returned.
   *
   * 
    
   *
   * 
    If no such constructor exists, and the given type is a primitive type, then the given value
   * is converted to a string using its {@link Object#toString() toString()} method, and that string
   * is parsed into the correct primitive type using, for instance, {@link Integer#valueOf(String)}
   * to convert the string into an {@code int}.
   *
   * 
    
   *
   * 
    If no special constructor exists and the given type is not a primitive type, this method
   * returns the original value.
   *
   * @param newType the type to convert the value to
   * @param value the value to convert
   * @return the converted value
   * @throws NumberFormatException if newType is a primitive type, and the string representation of
   *     the given value cannot be converted to that type
   * @throws InstantiationException if the constructor found with reflection raises it
   * @throws InvocationTargetException if the constructor found with reflection raises it
   * @throws IllegalAccessException never
   */
  @SuppressWarnings({"rawtypes", "unchecked"})
  protected Object convertType(Class newType, Object value)
      throws InstantiationException, IllegalAccessException, InvocationTargetException {
    // try call constructor
    Class[] types = {value.getClass()};
    try {
      Constructor constructor = newType.getConstructor(types);
      Object[] arguments = {value};
      return constructor.newInstance(arguments);
    } catch (NoSuchMethodException e) {
      // try using the transformers
      Function function = getTypeFunction(newType);
      if (function != null) {
        return function.apply(value);
      }
      return value;
    }
  }

  /**
   * Returns a transformer for the given primitive type.
   *
   * @param aType the primitive type whose transformer to return
   * @return a transformer that will convert strings into that type, or null if the given type is
   *     not a primitive type
   */
  protected Function getTypeFunction(Class aType) {
    return defaultFunctions.get(aType);
  }
}
    
    
    
    

    




    
    
    © 2015 - 2024 Weber Informatics LLC | Privacy Policy