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/*
* ============LICENSE_START=======================================================
* ONAP
* ================================================================================
* Copyright (C) 2018 AT&T Intellectual Property. All rights reserved.
* ================================================================================
* 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.
* ============LICENSE_END=========================================================
*/
package org.onap.policy.drools.util;
import java.lang.annotation.Annotation;
import java.lang.reflect.Field;
import java.util.Properties;
import org.onap.policy.common.utils.properties.SpecPropertyConfiguration;
import org.onap.policy.common.utils.properties.exception.PropertyException;
/**
* Checks whether or not a feature is enabled. The name of the "enable" property
* is assumed to be of the form accepted by a {@link SpecPropertyConfiguration},
* which contains a substitution place-holder into which a "specializer" (e.g.,
* controller or session name) is substituted.
*/
public class FeatureEnabledChecker {
/**
*
*/
private FeatureEnabledChecker() {
super();
}
/**
* Determines if a feature is enabled for a particular specializer.
*
* @param props properties from which to extract the "enabled" flag
* @param specializer specializer to be substituted into the property name
* when extracting
* @param propName the name of the "enabled" property
* @return {@code true} if the feature is enabled, or {@code false} if it is
* not enabled (or if the property doesn't exist)
* @throws IllegalArgumentException if the "enabled" property is not a
* boolean value
*/
public static boolean isFeatureEnabled(Properties props, String specializer, String propName) {
try {
return new Config(specializer, props, propName).isEnabled();
} catch (PropertyException e) {
throw new IllegalArgumentException("cannot check property " + propName, e);
}
}
/**
* Configuration used to extract the value.
*/
private static class Config extends SpecPropertyConfiguration {
/**
* There is a bit of trickery here. This annotation is just a
* place-holder to get the superclass to invoke the
* {@link #setValue(java.lang.reflect.Field, Properties, Property)
* setValue()} method. When that's invoked, we'll substitute
* {@link #propOverride} instead of this annotation.
*/
@Property(name = "feature-enabled-property-place-holder")
private boolean enabled;
/**
* Annotation that will actually be used to set the field.
*/
private Property propOverride;
/**
*
* @param specializer specializer to be substituted into the property
* name when extracting
* @param props properties from which to extract the "enabled" flag
* @param propName the name of the "enabled" property
* @throws PropertyException if an error occurs
*/
public Config(String specializer, Properties props, String propName) throws PropertyException {
super(specializer);
propOverride = new Property() {
@Override
public String name() {
return propName;
}
@Override
public String defaultValue() {
// feature is disabled by default
return "false";
}
@Override
public String accept() {
return "";
}
@Override
public Class<? extends Annotation> annotationType() {
return Property.class;
}
};
setAllFields(props);
}
/**
* Substitutes {@link #propOverride} for "prop".
*/
@Override
protected boolean setValue(Field field, Properties props, Property prop) throws PropertyException {
return super.setValue(field, props, propOverride);
}
/**
*
* @return {@code true} if the feature is enabled, {@code false}
* otherwise
*/
public boolean isEnabled() {
return enabled;
}
};
}
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