Find Field : Field « Reflection « Java






Find Field

     

//
//$Id: IntrospectionUtil.java 1540 2007-01-19 12:24:10Z janb $
//Copyright 2006 Mort Bay Consulting Pty. Ltd.
//------------------------------------------------------------------------
//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.
//

import java.lang.reflect.Field;
import java.lang.reflect.Member;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.util.Arrays;
import java.util.List;

public class IntrospectionUtil {


  public static Field findField(Class clazz, String targetName, Class targetType,
      boolean checkInheritance, boolean strictType) throws NoSuchFieldException {
    if (clazz == null)
      throw new NoSuchFieldException("No class");
    if (targetName == null)
      throw new NoSuchFieldException("No field name");

    try {
      Field field = clazz.getDeclaredField(targetName);
      if (strictType) {
        if (field.getType().equals(targetType))
          return field;
      } else {
        if (field.getType().isAssignableFrom(targetType))
          return field;
      }
      if (checkInheritance) {
        return findInheritedField(clazz.getPackage(), clazz.getSuperclass(), targetName,
            targetType, strictType);
      } else
        throw new NoSuchFieldException("No field with name " + targetName + " in class "
            + clazz.getName() + " of type " + targetType);
    } catch (NoSuchFieldException e) {
      return findInheritedField(clazz.getPackage(), clazz.getSuperclass(), targetName, targetType,
          strictType);
    }
  }

  public static boolean isInheritable(Package pack, Member member) {
    if (pack == null)
      return false;
    if (member == null)
      return false;

    int modifiers = member.getModifiers();
    if (Modifier.isPublic(modifiers))
      return true;
    if (Modifier.isProtected(modifiers))
      return true;
    if (!Modifier.isPrivate(modifiers) && pack.equals(member.getDeclaringClass().getPackage()))
      return true;

    return false;
  }

  public static boolean checkParams(Class[] formalParams, Class[] actualParams, boolean strict) {
    if (formalParams == null && actualParams == null)
      return true;
    if (formalParams == null && actualParams != null)
      return false;
    if (formalParams != null && actualParams == null)
      return false;

    if (formalParams.length != actualParams.length)
      return false;

    if (formalParams.length == 0)
      return true;

    int j = 0;
    if (strict) {
      while (j < formalParams.length && formalParams[j].equals(actualParams[j]))
        j++;
    } else {
      while ((j < formalParams.length) && (formalParams[j].isAssignableFrom(actualParams[j]))) {
        j++;
      }
    }

    if (j != formalParams.length) {
      return false;
    }

    return true;
  }

  public static boolean isSameSignature(Method methodA, Method methodB) {
    if (methodA == null)
      return false;
    if (methodB == null)
      return false;

    List parameterTypesA = Arrays.asList(methodA.getParameterTypes());
    List parameterTypesB = Arrays.asList(methodB.getParameterTypes());

    if (methodA.getName().equals(methodB.getName()) && parameterTypesA.containsAll(parameterTypesB))
      return true;

    return false;
  }

  public static boolean isTypeCompatible(Class formalType, Class actualType, boolean strict) {
    if (formalType == null && actualType != null)
      return false;
    if (formalType != null && actualType == null)
      return false;
    if (formalType == null && actualType == null)
      return true;

    if (strict)
      return formalType.equals(actualType);
    else
      return formalType.isAssignableFrom(actualType);
  }

  public static boolean containsSameMethodSignature(Method method, Class c, boolean checkPackage) {
    if (checkPackage) {
      if (!c.getPackage().equals(method.getDeclaringClass().getPackage()))
        return false;
    }

    boolean samesig = false;
    Method[] methods = c.getDeclaredMethods();
    for (int i = 0; i < methods.length && !samesig; i++) {
      if (IntrospectionUtil.isSameSignature(method, methods[i]))
        samesig = true;
    }
    return samesig;
  }

  public static boolean containsSameFieldName(Field field, Class c, boolean checkPackage) {
    if (checkPackage) {
      if (!c.getPackage().equals(field.getDeclaringClass().getPackage()))
        return false;
    }

    boolean sameName = false;
    Field[] fields = c.getDeclaredFields();
    for (int i = 0; i < fields.length && !sameName; i++) {
      if (fields[i].getName().equals(field.getName()))
        sameName = true;
    }
    return sameName;
  }

  protected static Method findInheritedMethod(Package pack, Class clazz, String methodName,
      Class[] args, boolean strictArgs) throws NoSuchMethodException {
    if (clazz == null)
      throw new NoSuchMethodException("No class");
    if (methodName == null)
      throw new NoSuchMethodException("No method name");

    Method method = null;
    Method[] methods = clazz.getDeclaredMethods();
    for (int i = 0; i < methods.length && method == null; i++) {
      if (methods[i].getName().equals(methodName) && isInheritable(pack, methods[i])
          && checkParams(methods[i].getParameterTypes(), args, strictArgs))
        method = methods[i];
    }
    if (method != null) {
      return method;
    } else
      return findInheritedMethod(clazz.getPackage(), clazz.getSuperclass(), methodName, args,
          strictArgs);
  }

  protected static Field findInheritedField(Package pack, Class clazz, String fieldName,
      Class fieldType, boolean strictType) throws NoSuchFieldException {
    if (clazz == null)
      throw new NoSuchFieldException("No class");
    if (fieldName == null)
      throw new NoSuchFieldException("No field name");
    try {
      Field field = clazz.getDeclaredField(fieldName);
      if (isInheritable(pack, field) && isTypeCompatible(fieldType, field.getType(), strictType))
        return field;
      else
        return findInheritedField(clazz.getPackage(), clazz.getSuperclass(), fieldName, fieldType,
            strictType);
    } catch (NoSuchFieldException e) {
      return findInheritedField(clazz.getPackage(), clazz.getSuperclass(), fieldName, fieldType,
          strictType);
    }
  }

}

   
    
    
    
    
  








Related examples in the same category

1.Field Reflection
2.How to set public field objects
3.Class Reflection: field informationClass Reflection: field information
4.Object Reflection: get field valueObject Reflection: get field value
5.Object Reflection: set valueObject Reflection: set value
6.Get field of a class object and set or get its value
7.All Fields Snippet
8.Field modifiers: isSynthetic, isEnumConstant
9.Field with annotations
10.Set private field value
11.Get fields of a class object
12.Get all object accessible public fields
13.Getting the Field Objects of a Class Object: By obtaining a list of all declared fields.
14.Getting the Field Objects of a Class Object: By obtaining a list of all public fields, both declared and inherited.
15.Getting the Field Objects of a Class Object: By obtaining a particular Field object.
16.Get all declared fields from a class
17.Retrieving a Predefined Color by Name
18.Get a variable value from the variable name
19.Fetches all fields of all access types from the supplied class and super classes
20.Checks whether the specified class contains a field matching the specified name.
21.whether given field is a "public static final" constant
22.Process bean properties getter by applying the JavaBean naming conventions.
23.Fetches the property descriptor for the named property of the supplied class
24.Return a list of all fields (whatever access status, and on whatever superclass they were defined) that can be found on this class.
25.Get all fields of a class.
26.Find field 2
27.Get class field/property
28.Accessible Field Iterator
29.Adds all Fields (from Class.getFields) to the list
30.Retrieve a value from a property
31.Set the value of the field of the object to the given value.
32.Fast Property accessor for a single class.