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Simplified JDBC access for simplified code.
/*
* ao-dbc - Simplified JDBC access for simplified code.
* Copyright (C) 2009, 2010, 2011, 2013, 2015, 2016 AO Industries, Inc.
* [email protected]
* 7262 Bull Pen Cir
* Mobile, AL 36695
*
* This file is part of ao-dbc.
*
* ao-dbc is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* ao-dbc is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with ao-dbc. If not, see valueOf(int) or valueOf(String) methods to create the object instance.
*
* @author AO Industries, Inc.
*/
public class AutoObjectFactory implements ObjectFactory {
static final String EOL = System.getProperty("line.separator");
/**
* Concurrent map can't store nulls, uses this in place of null values when lookup fails.
*/
private static final Method notExists;
static {
try {
notExists = AutoObjectFactory.class.getMethod("getValueOfStringMethod", Class.class);
} catch(NoSuchMethodException err) {
throw new RuntimeException(err);
}
}
private static final ConcurrentMap,Method> valueOfIntMethods = new ConcurrentHashMap<>();
/**
* Gets the valueOf(int) for the provided class or null if doesn't
* exist or is non-static or non-public.
*/
public static Method getValueOfIntMethod(Class clazz) {
Method existing = valueOfIntMethods.get(clazz);
if(existing==null) {
Method newMethod;
try {
newMethod = clazz.getMethod("valueOf", Integer.TYPE);
int mod = newMethod.getModifiers();
if(!Modifier.isStatic(mod) || !Modifier.isPublic(mod)) newMethod = notExists;
} catch(NoSuchMethodException err) {
newMethod = notExists;
}
existing = valueOfIntMethods.put(clazz, newMethod);
if(existing==null) existing = newMethod;
}
return existing==notExists ? null : existing;
}
private static final ConcurrentMap,Method> valueOfStringMethods = new ConcurrentHashMap<>();
/**
* Gets the valueOf(String) for the provided class or null if doesn't
* exist or is non-static or non-public.
*/
public static Method getValueOfStringMethod(Class clazz) {
//System.err.println("clazz="+clazz);
Method existing = valueOfStringMethods.get(clazz);
if(existing==null) {
Method newMethod;
try {
newMethod = clazz.getMethod("valueOf", String.class);
int mod = newMethod.getModifiers();
if(!Modifier.isStatic(mod) || !Modifier.isPublic(mod)) newMethod = notExists;
} catch(NoSuchMethodException err) {
newMethod = notExists;
}
existing = valueOfStringMethods.put(clazz, newMethod);
if(existing==null) existing = newMethod;
}
return existing==notExists ? null : existing;
}
private final Class clazz;
private final Object[] prefixParams;
public AutoObjectFactory(Class clazz, Object... prefixParams) {
this.clazz = clazz;
this.prefixParams = prefixParams;
}
/**
* Creates one object from the current values in the ResultSet. Looks for a
* constructor that is assignable to the prefixParams and the result set values.
* The constructor must exactly match the number of prefixParams plus the
* result set.
*/
@Override
public T createObject(ResultSet result) throws SQLException {
try {
ResultSetMetaData metaData = result.getMetaData();
int numColumns = metaData.getColumnCount();
int numParams = prefixParams.length + numColumns;
Object[] params = new Object[numParams];
// Find the candidate constructor
List warnings = null;
Constructor[] constructors = clazz.getConstructors();
CONSTRUCTORS :
for(Constructor constructor : constructors) {
Class[] paramTypes = constructor.getParameterTypes();
if(paramTypes.length==numParams) {
for(int i=0;i paramType = paramTypes[i];
if(!paramType.isAssignableFrom(prefixParams[i].getClass())) continue CONSTRUCTORS;
params[i] = prefixParams[i];
//System.err.println(paramType.getName()+" ? "+(params[i]==null ? "null" : params[i].getClass()));
}
// All remaining columns must be assignable from JDBC
for(int c=1; c<=numColumns; c++) {
int i = prefixParams.length + c-1;
Class paramType = paramTypes[i];
// String first because it is commonly used
if(paramType==String.class) {
params[i] = result.getString(c);
// Primitives
} else if(paramType==Integer.TYPE) {
int value = result.getInt(c);
if(result.wasNull()) throw new SQLException(c+": "+metaData.getColumnName(c)+": null int");
params[i] = value;
} else if(paramType==Short.TYPE) {
short value = result.getShort(c);
if(result.wasNull()) throw new SQLException(c+": "+metaData.getColumnName(c)+": null short");
params[i] = value;
} else if(paramType==Boolean.TYPE) {
boolean b = result.getBoolean(c);
if(result.wasNull()) throw new SQLException(c+": "+metaData.getColumnName(c)+": null boolean");
params[i] = b;
} else if(paramType==Float.TYPE) {
float value = result.getFloat(c);
if(result.wasNull()) throw new SQLException(c+": "+metaData.getColumnName(c)+": null float");
params[i] = value;
} else if(paramType==Long.TYPE) {
long value = result.getLong(c);
if(result.wasNull()) throw new SQLException(c+": "+metaData.getColumnName(c)+": null long");
params[i] = value;
// Other types
} else if(paramType==Date.class) {
params[i] = result.getDate(c);
} else if(paramType==Boolean.class) {
boolean b = result.getBoolean(c);
params[i] = result.wasNull() ? null : b;
} else if(paramType==Timestamp.class) {
params[i] = result.getTimestamp(c);
} else if(paramType==Integer.class) {
int value = result.getInt(c);
params[i] = result.wasNull() ? null : value;
} else if(paramType==Float.class) {
float value = result.getFloat(c);
params[i] = result.wasNull() ? null : value;
} else if(paramType==Short.class) {
short value = result.getShort(c);
params[i] = result.wasNull() ? null : value;
} else if(paramType==Long.class) {
long value = result.getLong(c);
params[i] = result.wasNull() ? null : value;
} else {
// Try to find valueOf(int) for unknown types
Method valueOfIntMethod = getValueOfIntMethod(paramType);
if(valueOfIntMethod!=null) {
int value = result.getInt(c);
if(result.wasNull()) params[i] = null;
params[i] = valueOfIntMethod.invoke(null, value);
} else {
// Try to find valueOf(String) for unknown types
Method valueOfStringMethod = getValueOfStringMethod(paramType);
if(valueOfStringMethod!=null) {
String value = result.getString(c);
params[i] = result.wasNull() ? null : valueOfStringMethod.invoke(null, value);
} else {
if(warnings==null) warnings = new ArrayList<>();
warnings.add("Unexpected parameter class: "+paramType.getName());
continue CONSTRUCTORS;
}
}
}
//System.err.println(paramType.getName()+" ? "+(params[i]==null ? "null" : params[i].getClass()));
}
Object newInstance = constructor.newInstance(params);
//System.err.println(newInstance.getClass().getName()+": "+newInstance);
return clazz.cast(newInstance);
}
}
StringBuilder message = new StringBuilder("Unable to find matching constructor");
if(warnings!=null) for(String warning : warnings) message.append(EOL).append(warning);
throw new SQLException(message.toString());
} catch(InstantiationException | IllegalAccessException | InvocationTargetException err) {
throw new SQLException(err);
}
}
}