com.enonic.cms.framework.util.PropertiesUtil.java Source code

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Here is the source code for com.enonic.cms.framework.util.PropertiesUtil.java

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/*
 * Copyright 2000-2011 Enonic AS
 * http://www.enonic.com/license
 */
package com.enonic.cms.framework.util;

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

import org.apache.commons.lang.text.StrLookup;
import org.apache.commons.lang.text.StrSubstitutor;

/**
 * This class implements properties utility methods.
 */
public final class PropertiesUtil {
    /**
     * Return a subset of properties.
     */
    public static Properties getSubSet(final Properties props, final String base) {
        Properties sub = new Properties();
        for (Map.Entry entry : props.entrySet()) {
            String key = (String) entry.getKey();
            String value = (String) entry.getValue();

            if (key.startsWith(base)) {
                sub.setProperty(key.substring(base.length()), value);
            }
        }

        return sub;
    }

    /**
     * Interpolate properties names like ${..}.
     */
    public static Properties interpolate(final Properties props) {
        Properties target = new Properties();

        Properties source = new Properties();
        source.putAll(System.getProperties());
        source.putAll(props);

        StrLookup lookup = StrLookup.mapLookup(source);
        StrSubstitutor substitutor = new StrSubstitutor(lookup);

        for (Object key : props.keySet()) {
            String value = props.getProperty((String) key);

            try {
                value = substitutor.replace(value);
            } catch (IllegalStateException e) {
                // Do nothing
            }

            target.put(key, value);
        }

        return target;
    }
}