org.apache.ws.commons.schema.utils.CollectionFactory Maven / Gradle / Ivy
/**
* 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
* 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 org.apache.ws.commons.schema.utils;
import java.security.AccessController;
import java.security.PrivilegedAction;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
/**
* There are many collections of XML Schema objects inside XmlSchema. This class provides consistent
* construction to centralize policy for thread synchronization and the like.
*/
public final class CollectionFactory {
private static final String PROTECT_READ_ONLY_COLLECTIONS_PROP =
"org.apache.ws.commons.schema.protectReadOnlyCollections";
private static final boolean DEFAULT_PROTECT_READ_ONLY_COLLECTIONS;
private static final ThreadLocal PROTECT_READ_ONLY_COLLECTIONS = new ThreadLocal();
static {
DEFAULT_PROTECT_READ_ONLY_COLLECTIONS = AccessController.doPrivileged(new PrivilegedAction() {
public Boolean run() {
return Boolean.parseBoolean(System.getProperty(PROTECT_READ_ONLY_COLLECTIONS_PROP));
}
});
}
private CollectionFactory() {
}
public static List getList(Class type) {
return Collections.synchronizedList(new ArrayList());
}
public static Set getSet(Class type) {
return Collections.synchronizedSet(new HashSet());
}
private static boolean isProtected() {
Boolean b = PROTECT_READ_ONLY_COLLECTIONS.get();
if (b == null) {
return DEFAULT_PROTECT_READ_ONLY_COLLECTIONS;
}
return b.booleanValue();
}
/**
* Turns on or off protection of collections for this thread.
* Note that this sets a thread local. If you want to return the
* thread to default state, use the clearProtection method.
* @param b
*/
public static void setProtected(boolean b) {
PROTECT_READ_ONLY_COLLECTIONS.set(b);
}
public static void clearProtection() {
PROTECT_READ_ONLY_COLLECTIONS.remove();
}
/**
* Call this to obtain a list to return from a public API where the caller is not supposed to modify the
* list. If org.apache.ws.commons.schema.protectReadOnlyCollections is 'true', this will return a list
* that checks at runtime.
*
* @param Generic parameter type of the list.
* @param list the list.
* @return
*/
public static List getProtectedList(List list) {
if (isProtected()) {
return Collections.unmodifiableList(list);
} else {
return list;
}
}
/**
* Call this to obtain a map to return from a public API where the caller is not supposed to modify the
* map. If org.apache.ws.commons.schema.protectReadOnlyCollections is 'true', this will return a map that
* checks at runtime.
*
* @param key type
* @param value type
* @param map the map.
* @return
*/
public static Map getProtectedMap(Map map) {
if (isProtected()) {
return Collections.unmodifiableMap(map);
} else {
return map;
}
}
public static void withSchemaModifiable(Runnable action) {
Boolean saved = PROTECT_READ_ONLY_COLLECTIONS.get();
try {
PROTECT_READ_ONLY_COLLECTIONS.set(Boolean.FALSE);
action.run();
} finally {
if (saved == null) {
PROTECT_READ_ONLY_COLLECTIONS.remove();
} else {
PROTECT_READ_ONLY_COLLECTIONS.set(saved);
}
}
}
}