org.springframework.batch.repeat.context.SynchronizedAttributeAccessor Maven / Gradle / Ivy
/*
* Copyright 2006-2007 the original author or authors.
*
* 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
*
* https://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.springframework.batch.repeat.context;
import org.springframework.core.AttributeAccessor;
import org.springframework.core.AttributeAccessorSupport;
/**
* An {@link AttributeAccessor} that synchronizes on a mutex (not this) before
* modifying or accessing the underlying attributes.
*
* @author Dave Syer
*
*/
public class SynchronizedAttributeAccessor implements AttributeAccessor {
/**
* All methods are delegated to this support object.
*/
AttributeAccessorSupport support = new AttributeAccessorSupport() {
/**
* Generated serial UID.
*/
private static final long serialVersionUID = -7664290016506582290L;
};
/*
* (non-Javadoc)
* @see org.springframework.core.AttributeAccessor#attributeNames()
*/
@Override
public String[] attributeNames() {
synchronized (support) {
return support.attributeNames();
}
}
/*
* (non-Javadoc)
* @see java.lang.Object#equals(java.lang.Object)
*/
@Override
public boolean equals(Object other) {
if (this == other) {
return true;
}
AttributeAccessorSupport that;
if (other instanceof SynchronizedAttributeAccessor) {
that = ((SynchronizedAttributeAccessor) other).support;
}
else if (other instanceof AttributeAccessorSupport) {
that = (AttributeAccessorSupport) other;
}
else {
return false;
}
synchronized (support) {
return support.equals(that);
}
}
/*
* (non-Javadoc)
* @see org.springframework.core.AttributeAccessor#getAttribute(java.lang.String)
*/
@Override
public Object getAttribute(String name) {
synchronized (support) {
return support.getAttribute(name);
}
}
/*
* (non-Javadoc)
* @see org.springframework.core.AttributeAccessor#hasAttribute(java.lang.String)
*/
@Override
public boolean hasAttribute(String name) {
synchronized (support) {
return support.hasAttribute(name);
}
}
/*
* (non-Javadoc)
* @see java.lang.Object#hashCode()
*/
@Override
public int hashCode() {
return support.hashCode();
}
/*
* (non-Javadoc)
* @see org.springframework.core.AttributeAccessor#removeAttribute(java.lang.String)
*/
@Override
public Object removeAttribute(String name) {
synchronized (support) {
return support.removeAttribute(name);
}
}
/*
* (non-Javadoc)
* @see org.springframework.core.AttributeAccessor#setAttribute(java.lang.String,
* java.lang.Object)
*/
@Override
public void setAttribute(String name, Object value) {
synchronized (support) {
support.setAttribute(name, value);
}
}
/**
* Additional support for atomic put if absent.
* @param name the key for the attribute name
* @param value the value of the attribute
* @return null if the attribute was not already set, the existing value
* otherwise.
*/
public Object setAttributeIfAbsent(String name, Object value) {
synchronized (support) {
Object old = getAttribute(name);
if (old != null) {
return old;
}
setAttribute(name, value);
}
return null;
}
/*
* (non-Javadoc)
* @see java.lang.Object#toString()
*/
@Override
public String toString() {
StringBuilder buffer = new StringBuilder("SynchronizedAttributeAccessor: [");
synchronized (support) {
String[] names = attributeNames();
for (int i = 0; i < names.length; i++) {
String name = names[i];
buffer.append(names[i]).append("=").append(getAttribute(name));
if (i < names.length - 1) {
buffer.append(", ");
}
}
buffer.append("]");
return buffer.toString();
}
}
}