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);
}
}
}
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