eu.unicore.persist.impl.ClassScanner Maven / Gradle / Ivy
package eu.unicore.persist.impl;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.util.ArrayList;
import java.util.List;
import eu.unicore.persist.annotations.Column;
import eu.unicore.persist.annotations.ID;
import eu.unicore.persist.annotations.Table;
/**
* Helper for evaluating annotations on a persistent class
*
* @see PersistenceDescriptor
* @author schuller
*/
public class ClassScanner {
private ClassScanner(){}
/**
* figure out the table name to use. If no {@link Table} annotation is
* present, the class name is used as default
*
* @param daoClass
* @return table name
*/
public static String getTableName(ClassdaoClass){
if(daoClass.getAnnotation(Table.class)!=null){
return ((Table)daoClass.getAnnotation(Table.class)).name();
}
return daoClass.getSimpleName();
}
/**
* retrieve the {@link Method} to use for getting the unique ID
* of an entity. This is selected by an {@link ID} annotation,
* either on a field (which MUST have an associated getNNN() method!!)
* or on a method.
* Both field and method must be of type {@link String}
*
* @param daoClass - the Class of the entity
* @return
*/
public static Method getGetIdMethod(ClassdaoClass){
for(Method m: daoClass.getDeclaredMethods()){
if(m.getAnnotation(ID.class)!=null){
if(!String.class.equals(m.getReturnType())){
throw new IllegalArgumentException("ID method must return java.lang.String");
}
return m;
}
}
//else check if a field has the required annotation
for(Field f: daoClass.getDeclaredFields()){
if(f.getAnnotation(ID.class)!=null){
//find getter
String name="get"+f.getName();
Method m=findMethod(daoClass, name);
if(m!=null){
if(!String.class.equals(m.getReturnType())){
throw new IllegalArgumentException("ID method must return java.lang.String");
}
return m;
}
}
}
throw new IllegalArgumentException("Class has no useable ID annotation!");
}
public static List getColumns(ClassdaoClass){
Listresult=new ArrayList();
for(Method m: daoClass.getDeclaredMethods()){
if(m.getAnnotation(Column.class)!=null){
String name=((Column)m.getAnnotation(Column.class)).name();
ColumnDescriptor cd=new ColumnDescriptor(m,name);
result.add(cd);
}
}
//else check if a field has the required annotation
for(Field f: daoClass.getDeclaredFields()){
if(f.getAnnotation(Column.class)!=null){
//find getter
String name="get"+f.getName();
Method m=findMethod(daoClass, name);
if(m==null)throw new IllegalArgumentException("Can't find getter method for column "+f.getName());
String columnName=((Column)f.getAnnotation(Column.class)).name();
if(columnName==null)columnName=f.getName();
ColumnDescriptor cd=new ColumnDescriptor(m,columnName);
result.add(cd);
}
}
return result;
}
private static Method findMethod(ClassdaoClass, String name){
for(Method m: daoClass.getDeclaredMethods()){
if(m.getName().equalsIgnoreCase(name)){
return m;
}
}
return null;
}
}