com.netflix.nfsidecar.configSource.SystemPropertiesConfigSource Maven / Gradle / Ivy

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package com.netflix.nfsidecar.configSource;

import java.util.Map;
import java.util.Properties;

import com.google.common.base.Preconditions;
import com.google.common.collect.Maps;

/**
 * Loads {@link System#getProperties()} as a source.
 *
 * Implementation note: {@link #set(String, String)} does not write to system properties, but will write to a new map.
 * This means that setting values to this source has no effect on system properties or other instances of this class.
 */
public final class SystemPropertiesConfigSource extends AbstractConfigSource 
{
    private static final String BLANK = "";

    private final Map data = Maps.newConcurrentMap();

    @Override
    public void intialize(final String asgName, final String region) 
    {
        super.intialize(asgName, region);

        Properties systemProps = System.getProperties();

        for (final String key : systemProps.stringPropertyNames()) 
        {
            final String value = systemProps.getProperty(key);
            if (value != null && !BLANK.equals(value)) 
            {
                data.put(key, value);
            }
        }
    }

    @Override
    public int size() 
    {
        return data.size();
    }

    @Override
    public String get(final String key) 
    {
        return data.get(key);
    }

    @Override
    public void set(final String key, final String value) 
    {
        Preconditions.checkNotNull(value, "Value can not be null for configurations.");
        data.put(key, value);
    }
}