// Licensed to the Apache Software Foundation (ASF) under one

// or more contributor license agreements. See the NOTICE file

// distributed with this work for additional information

// regarding copyright ownership. The ASF licenses this file

// to you under the Apache License, Version 2.0 (the

// "License"); you may not use this file except in compliance

// 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.cloud.utils.db;

import java.lang.reflect.Method;

import java.util.Collection;

import java.util.HashMap;

import java.util.Map;

import net.sf.cglib.proxy.MethodInterceptor;

import net.sf.cglib.proxy.MethodProxy;

import com.cloud.utils.Ternary;

import com.cloud.utils.exception.CloudRuntimeException;

public class UpdateBuilder implements MethodInterceptor {

protected Map<String, Ternary<Attribute, Boolean, Object>> _changes;

protected HashMap<Attribute, Object> _collectionChanges;

protected GenericDaoBase<?, ?> _dao;

protected UpdateBuilder(GenericDaoBase<?, ?> dao) {

_dao = dao;

_changes = new HashMap<String, Ternary<Attribute, Boolean, Object>>();

}

@Override

public Object intercept(Object object, Method method, Object[] args, MethodProxy methodProxy) throws Throwable {

String name = method.getName();

if (name.startsWith("set")) {

String field = methodToField(name, 3);

makeChange(field, args[0]);

} else if (name.startsWith("incr")) {

makeIncrChange(name, args);

} else if (name.startsWith("decr")) {

makeDecrChange(name, args);

}

return methodProxy.invokeSuper(object, args);

}

private final String methodToField(String method, int start) {

char[] chs = method.toCharArray();

chs[start] = Character.toLowerCase(chs[start]);

return new String(chs, start, chs.length - start);

}

protected Attribute makeChange(String field, Object value) {

Attribute attr = _dao._allAttributes.get(field);

assert (attr == null || attr.isUpdatable()) : "Updating an attribute that's not updatable: " + field;

if (attr != null) {

if (attr.attache == null) {

_changes.put(field, new Ternary<Attribute, Boolean, Object>(attr, null, value));

} else {

if (_collectionChanges == null) {

_collectionChanges = new HashMap<Attribute, Object>();

}

_collectionChanges.put(attr, value);

}

}

return attr;

}

protected void makeIncrChange(String method, Object[] args) {

String field = methodToField(method, 4);

Attribute attr = _dao._allAttributes.get(field);

assert (attr != null && attr.isUpdatable()) : "Updating an attribute that's not updatable: " + field;

incr(attr, args == null || args.length == 0 ? 1 : args[0]);

}

protected void makeDecrChange(String method, Object[] args) {

String field = methodToField(method, 4);

Attribute attr = _dao._allAttributes.get(field);

assert (attr != null && attr.isUpdatable()) : "Updating an attribute that's not updatable: " + field;

decr(attr, args == null || args.length == 0 ? 1 : args[0]);

}

public void set(Object entity, String name, Object value) {

Attribute attr = makeChange(name, value);

set(entity, attr, value);

}

public void set(Object entity, Attribute attr, Object value) {

_changes.put(attr.field.getName(), new Ternary<Attribute, Boolean, Object>(attr, null, value));

try {

attr.field.set(entity, value);

} catch (IllegalArgumentException e) {

throw new CloudRuntimeException("Unable to update " + attr.field.getName() + " with " + value, e);

} catch (IllegalAccessException e) {

throw new CloudRuntimeException("Unable to update " + attr.field.getName() + " with " + value, e);

}

}

public void incr(Attribute attr, Object value) {

_changes.put(attr.field.getName(), new Ternary<Attribute, Boolean, Object>(attr, true, value));

}

public void decr(Attribute attr, Object value) {

_changes.put(attr.field.getName(), new Ternary<Attribute, Boolean, Object>(attr, false, value));

}

public boolean hasChanges() {

return (_changes.size() + (_collectionChanges != null ? _collectionChanges.size() : 0)) != 0;

}

public boolean has(String name) {

return _changes.containsKey(name);

}

public Map<Attribute, Object> getCollectionChanges() {

return _collectionChanges;

}

public void clear() {

_changes.clear();

if (_collectionChanges != null) {

_collectionChanges.clear();

_collectionChanges = null;

}

}

public StringBuilder toSql(String tables) {

if (_changes.isEmpty()) {

return null;

}

return SqlGenerator.buildMysqlUpdateSql(tables, _changes.values());

}

public Collection<Ternary<Attribute, Boolean, Object>> getChanges() {

return _changes.values();

}

}