io.milton.context.RequestContext Maven / Gradle / Ivy
/*
*
* Copyright 2014 McEvoy Software 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.
*/
package io.milton.context;
import java.util.ArrayList;
public class RequestContext extends Context implements RemovalCallback {
private static final ThreadLocal tlContext = new ThreadLocal<>();
private final RootContext parent;
/**
* For convenience, equivalent to RequestContext.getCurrent().get(c)
*
* This method assumes that the requested class is required and will throw
* an exception if it is not found
*
* @param - the type expected to be returned
* @param c - the class to
* @return - an object of the given type
*/
public static T C(Class c) throws ClassNotInContextException {
T t = getCurrent().get(c);
if (t == null) {
throw new ClassNotInContextException(c);
}
return t;
}
/**
* For convenience, equivalent to RequestContext.getCurrent().get(c)
*
* Returns the object in context of the given type or null if not found and
* required is false.
*
* @param
* @param c
* @param required - if true will throw an exception if the requested class
* is not found. Otherwise will return null.
* @return - an object of the given type
*/
public static T C(Class c, boolean required) throws ClassNotInContextException {
T t = getCurrent().get(c);
if (t == null && required) {
throw new ClassNotInContextException(c);
}
return t;
}
public static RequestContext getCurrent() {
return tlContext.get();
}
static void setCurrent(RequestContext rc) {
if (rc == null) {
tlContext.remove();
} else {
tlContext.set(rc);
}
}
public static RequestContext getInstance(RootContext parent) {
RequestContext c = getCurrent();
if (c == null) {
c = new RequestContext(parent);
setCurrent(c);
}
return c;
}
public static RequestContext peekInstance() {
return getCurrent();
}
private RequestContext(RootContext parent) {
if (parent == null) {
throw new IllegalArgumentException("parent cannot be null");
}
this.parent = parent;
}
public RootContext getRootContext() {
return parent;
}
@Override
protected Registration getRegistration(Class c) {
return getOrCreateRegistration(c, this);
}
@Override
protected Registration getRegistration(String id) {
return getOrCreateRegistration(id, this);
}
@Override
protected Registration getOrCreateRegistration(Class c, Context context) {
Registration reg = super.getRegistration(c);
if (reg != null) {
return reg;
}
return parent.getOrCreateRegistration(c, this);
}
@Override
Registration getOrCreateRegistration(String id, Context context) {
Registration reg = super.getRegistration(id);
if (reg != null) {
return reg;
}
return parent.getRegistration(id);
}
/**
* Called when this request context goes out of context. Should shutdown all
* of its contents
*/
@Override
public void onRemove(Object item) {
tlContext.remove();
ArrayList items = new ArrayList<>(this.itemByClass.values());
for (Registration reg : items) {
reg.remove();
}
}
}