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Collection of reusable (not depending on any other UberFire module) components for Uberfire.
There is a newer version: 7.74.1.Final
package org.uberfire.commons.config;

import static org.uberfire.commons.validation.PortablePreconditions.*;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Properties;

/**
 * Encapsulates a collection of Java System Properties by name and value. Includes handy methods for providing and
 * identifying application-provided default values and converting from Strings to other common types.
 */
public class ConfigProperties {

    private final Map configuredValues;
    private final List configSummary = new ArrayList();

    /**
     * Creates a new container of configured values from which specific config properties can be obtained.
     *
     * @param configuredValues
     *            The configured values, which may have been hardcoded in a Map, read from a config file, or whatever.
     */
    public ConfigProperties(Map configuredValues) {
        this.configuredValues = checkNotNull( "configuredValues", configuredValues );
    }

    /**
     * Creates a new container of configured values from which specific config properties can be obtained.
     *
     * @param configuredValues
     *            The configured values, which may have been read from a properties file, or obtained from
     *            {@link System#getProperties()}. If the property set contains entries whose key and value are not both
     *            Strings, these entries will be ignored.
     */
    public ConfigProperties(Properties configuredValues) {
        Map stringProperties = new HashMap();
        for ( String key : configuredValues.stringPropertyNames() ) {
            stringProperties.put( key, configuredValues.getProperty( key ) );
        }
        this.configuredValues = stringProperties;
    }

    /**
     * Returns the ConfigProperty instance corresponding to the configured value of the given property, or the default
     * if no configured value exists.
     *
     * @param name
     *            the property name. Must not be null.
     * @param defaultValue
     *            the value to use if no configured value exists. May be null.
     * @return
     */
    public ConfigProperty get( String name, String defaultValue ) {
        String val = configuredValues.get( name );
        ConfigProperty cp;
        if ( val == null || val.trim().length() == 0 ) {
            cp = new ConfigProperty( name, defaultValue, true );
        } else {
            cp = new ConfigProperty( name, val.trim(), false );
        }
        configSummary.add( cp );
        return cp;
    }

    /**
     * Returns a multi-line string containing a list of all the properties that were retrieved from this instance, in
     * the order they were retrieved. Does not list unused values from the map given in the constructor, since these may
     * contain a lot of unrelated information (for example, when using System.getProperties()). This is useful for
     * printing a summary of the configuration in a given subsystem. It also helps users learn about available
     * configuration values.
     *
     * @param heading
     *            a line of text to print before listing the configuration values
     */
    public String getConfigurationSummary( String heading ) {
        final String newLine = System.getProperty( "line.separator" );
        StringBuilder sb = new StringBuilder( heading );
        for ( ConfigProperty cp : configSummary ) {
            sb.append( newLine ).append( cp );
        }
        return sb.toString();
    }

    public static class ConfigProperty {

        private final String name;
        private final String value;
        private final boolean isDefault;

        ConfigProperty(String name, String value, boolean isDefault) {
            this.name = name;
            this.value = value;
            this.isDefault = isDefault;
        }

        /**
         * Returns the name (map key) of this property.
         */
        public String getName() {
            return name;
        }

        /**
         * Returns the value of this property, which may or may not have been the default value.
         *
         * @see #isDefault()
         * @return the property value. Will be null if both the configured value was missing and the default was given
         *         as null.
         */
        public String getValue() {
            return value;
        }

        /**
         * Returns false if this value appeared among the user-supplied values; false if it came from the
         * application-provided default.
         *
         * @return whether this value is a default
         */
        public boolean isDefault() {
            return isDefault;
        }

        /**
         * Returns the boolean value of this property, converting from string using the same rules as
         * {@link Boolean#valueOf(String)}.
         */
        public boolean getBooleanValue() {
            return Boolean.valueOf( value );
        }

        /**
         * Returns the integer value of this property, converting from string using the same rules as
         * {@link Integer#parseInt(String)}.
         *
         * @throws NumberFormatException
         *             if the value cannot be parsed as an integer.
         */
        public int getIntValue() {
            return Integer.parseInt( value );
        }

        @Override
        public String toString() {
            return name + " = \"" + value + "\"" + (isDefault ? " (Defaulted)" : "");
        }
    }

}