com.github.ngoanh2n.PropFile Maven / Gradle / Ivy

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package com.github.ngoanh2n;

import javax.annotation.ParametersAreNonnullByDefault;
import java.io.File;
import java.util.Properties;

/**
 * Reads properties file.
 *
 * @author Ho Huu Ngoan ([email protected])
 */
@ParametersAreNonnullByDefault
public class PropFile {
    private Properties props;

    /**
     * Constructs this with a resource name.
     *
     * @param name Name of properties file in resources dir.
     */
    public PropFile(String name) {
        loadPropFile(name);
    }

    /**
     * Constructs this with a {@link File}.
     *
     * @param file Properties file in resources dir.
     */
    public PropFile(File file) {
        loadPropFile(file);
    }

    //-------------------------------------------------------------------------------//

    /**
     * Get property value.

     * Priority order: JVM System Property > Properties file.
     *
     * @param name The name of a property.
     * @return The value of a property as {@link String}.
     */
    public synchronized String getPropValue(String name) {
        return getPropValue(Prop.string(name));
    }

    /**
     * Get property object.

     * Priority order: JVM System Property > Properties file > Default value.
     *
     * @param prop {@link Prop} object.
     * @return The value of a property.
     */
    public synchronized  T getPropValue(Prop prop) {
        String name = prop.getName();
        Class type = prop.getType();
        T value = new Prop<>(name, type).getValue();

        if (value == null) {
            String valueStr = props.getProperty(name);
            if (valueStr == null) {
                return prop.getDefaultValue();
            } else {
                return Commons.convertValue(type, valueStr);
            }
        }
        return value;
    }

    //-------------------------------------------------------------------------------//

    private void loadPropFile(String name) {
        try {
            File file = Resource.getFile(name);
            loadPropFile(file);
        } catch (RuntimeError ignored) {
            props = new Properties();
        }
    }

    private void loadPropFile(File file) {
        if (props == null) {
            try {
                props = Commons.readProps(file, "UTF-8");
            } catch (RuntimeError ignored) {
                props = new Properties();
            }
        }
    }
}