org.springframework.web.context.support.ServletContextParameterFactoryBean Maven / Gradle / Ivy
/*
* Copyright 2002-2017 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.web.context.support;
import javax.servlet.ServletContext;
import org.springframework.beans.factory.FactoryBean;
import org.springframework.lang.Nullable;
import org.springframework.web.context.ServletContextAware;
/**
* {@link FactoryBean} that retrieves a specific ServletContext init parameter
* (that is, a "context-param" defined in {@code web.xml}).
* Exposes that ServletContext init parameter when used as bean reference,
* effectively making it available as named Spring bean instance.
*
* NOTE: As of Spring 3.0, you may also use the "contextParameters" default
* bean which is of type Map, and dereference it using an "#{contextParameters.myKey}"
* expression to access a specific parameter by name.
*
* @author Juergen Hoeller
* @since 1.2.4
* @see org.springframework.web.context.WebApplicationContext#CONTEXT_PARAMETERS_BEAN_NAME
* @see ServletContextAttributeFactoryBean
*/
public class ServletContextParameterFactoryBean implements FactoryBean, ServletContextAware {
@Nullable
private String initParamName;
@Nullable
private String paramValue;
/**
* Set the name of the ServletContext init parameter to expose.
*/
public void setInitParamName(String initParamName) {
this.initParamName = initParamName;
}
@Override
public void setServletContext(ServletContext servletContext) {
if (this.initParamName == null) {
throw new IllegalArgumentException("initParamName is required");
}
this.paramValue = servletContext.getInitParameter(this.initParamName);
if (this.paramValue == null) {
throw new IllegalStateException("No ServletContext init parameter '" + this.initParamName + "' found");
}
}
@Override
@Nullable
public String getObject() {
return this.paramValue;
}
@Override
public Class getObjectType() {
return String.class;
}
@Override
public boolean isSingleton() {
return true;
}
}