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Code Issues Actions 8 Packages Projects Releases Wiki Activity

Warn re Environment construction and instance vars 

- Add warning regarding access to default instance variable values
   during AbstractEnvironment#customizePropertySources callback

 - Polish AbstractEnvironment Javadoc and formatting

Issue: SPR-9013
This commit is contained in:
Chris Beams 2012-02-16 20:51:05 +01:00
parent 80dd32e95c
commit 7535e24deb
1 changed files with 56 additions and 17 deletions
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73
org.springframework.core/src/main/java/org/springframework/core/env/AbstractEnvironment.java vendored
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@ -1,5 +1,5 @@
/*
* Copyright 2002-2011 the original author or authors.
* Copyright 2002-2012 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.
@ -16,11 +16,8 @@
package org.springframework.core.env;
import static java.lang.String.format;
import static org.springframework.util.StringUtils.commaDelimitedListToStringArray;
import static org.springframework.util.StringUtils.trimAllWhitespace;
import java.security.AccessControlException;
import java.util.Collections;
import java.util.LinkedHashSet;
import java.util.Map;
@ -28,10 +25,14 @@ import java.util.Set;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.core.convert.support.ConfigurableConversionService;
import org.springframework.util.Assert;
import org.springframework.util.StringUtils;
import static java.lang.String.*;
import static org.springframework.util.StringUtils.*;
/**
* Abstract base class for {@link Environment} implementations. Supports the notion of
* reserved default profile names and enables specifying active and default profiles
@ -89,19 +90,39 @@ public abstract class AbstractEnvironment implements ConfigurableEnvironment {
protected final Log logger = LogFactory.getLog(getClass());
private Set<String> activeProfiles = new LinkedHashSet<String>();
private Set<String> defaultProfiles = new LinkedHashSet<String>(this.getReservedDefaultProfiles());
private final MutablePropertySources propertySources = new MutablePropertySources(logger);
private final ConfigurablePropertyResolver propertyResolver = new PropertySourcesPropertyResolver(propertySources);
private Set<String> defaultProfiles =
new LinkedHashSet<String>(this.getReservedDefaultProfiles());
private final MutablePropertySources propertySources =
new MutablePropertySources(this.logger);
private final ConfigurablePropertyResolver propertyResolver =
new PropertySourcesPropertyResolver(this.propertySources);
/**
* Create a new {@code Environment} instance, calling back to
* {@link #customizePropertySources(MutablePropertySources)} during construction to
* allow subclasses to contribute or manipulate {@link PropertySource} instances as
* appropriate.
* @see #customizePropertySources(MutablePropertySources)
*/
public AbstractEnvironment() {
String name = this.getClass().getSimpleName();
logger.debug(String.format("Initializing new %s", name));
this.customizePropertySources(propertySources);
logger.debug(String.format("Initialized %s with PropertySources %s", name, propertySources));
if (this.logger.isDebugEnabled()) {
this.logger.debug(format("Initializing new %s", name));
}
this.customizePropertySources(this.propertySources);
if (this.logger.isDebugEnabled()) {
this.logger.debug(format(
"Initialized %s with PropertySources %s", name, this.propertySources));
}
}
/**
* Customize the set of {@link PropertySource} objects to be searched by this
* {@code Environment} during calls to {@link #getProperty(String)} and related
@ -163,6 +184,17 @@ public abstract class AbstractEnvironment implements ConfigurableEnvironment {
* env.getPropertySources().addLast(new PropertySourceX(...));
* </pre>
*
* <h2>A warning about instance variable access</h2>
* Instance variables declared in subclasses and having default initial values should
* <em>not</em> be accessed from within this method. Due to Java object creation
* lifecycle constraints, any initial value will not yet be assigned when this
* callback is invoked by the {@link #AbstractEnvironment()} constructor, which may
* lead to a {@code NullPointerException} or other problems. If you need to access
* default values of instance variables, leave this method as a no-op and perform
* property source manipulation and instance variable access directly within the
* subclass constructor. Note that <em>assigning</em> values to instance variables is
* not problematic; it is only attempting to read default values that must be avoided.
*
* @see MutablePropertySources
* @see PropertySourcesPropertyResolver
* @see org.springframework.context.ApplicationContextInitializer
@ -217,7 +249,9 @@ public abstract class AbstractEnvironment implements ConfigurableEnvironment {
}
public void addActiveProfile(String profile) {
logger.debug(String.format("Activating profile '%s'", profile));
if (this.logger.isDebugEnabled()) {
this.logger.debug(format("Activating profile '%s'", profile));
}
this.validateProfile(profile);
this.activeProfiles.add(profile);
}
@ -312,8 +346,10 @@ public abstract class AbstractEnvironment implements ConfigurableEnvironment {
}
catch (AccessControlException ex) {
if (logger.isInfoEnabled()) {
logger.info(format("Caught AccessControlException when accessing system environment variable " +
"[%s]; its value will be returned [null]. Reason: %s", variableName, ex.getMessage()));
logger.info(format("Caught AccessControlException when " +
"accessing system environment variable [%s]; its " +
"value will be returned [null]. Reason: %s",
variableName, ex.getMessage()));
}
return null;
}
@ -338,8 +374,10 @@ public abstract class AbstractEnvironment implements ConfigurableEnvironment {
}
catch (AccessControlException ex) {
if (logger.isInfoEnabled()) {
logger.info(format("Caught AccessControlException when accessing system property " +
"[%s]; its value will be returned [null]. Reason: %s", propertyName, ex.getMessage()));
logger.info(format("Caught AccessControlException when " +
"accessing system property [%s]; its value will be " +
"returned [null]. Reason: %s",
propertyName, ex.getMessage()));
}
return null;
}
@ -428,7 +466,8 @@ public abstract class AbstractEnvironment implements ConfigurableEnvironment {
@Override
public String toString() {
return format("%s {activeProfiles=%s, defaultProfiles=%s, propertySources=%s}",
getClass().getSimpleName(), this.activeProfiles, this.defaultProfiles, this.propertySources);
getClass().getSimpleName(), this.activeProfiles, this.defaultProfiles,
this.propertySources);
}
}