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/*
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
 *
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 * and Distribution License("CDDL") (collectively, the "License").  You
 * may not use this file except in compliance with the License.  You can
 * obtain a copy of the License at
 * http://glassfish.java.net/public/CDDL+GPL_1_1.html
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package org.glassfish.jersey.internal.util;

import java.lang.reflect.Constructor;
import java.lang.reflect.Method;
import java.util.Map;

/**
 * Helper class containing convenience methods for reading
 * {@link org.glassfish.jersey.server.ResourceConfig} and {@link javax.ws.rs.client.Configuration} properties.
 *
 * @author Martin Matula (martin.matula at oracle.com)
 */
public class PropertiesHelper {
    /**
     * Returns value of a specified property. If the property is not set or the real value type is not compatible with
     * defaultValue type, the specified defaultValue is returned. Calling this method is equivalent to calling
     * {@code PropertyHelper.getValue(properties, key, defaultValue, (Class) defaultValue.getClass())}
     *
     * @param properties Map of properties to get the property value from.
     * @param key Name of the property.
     * @param defaultValue Default value to be returned if the specified property is not set or cannot be read.
     * @param  Type of the property value.
     * @return Value of the property or defaultValue.
     */
    public static  T getValue(Map properties, String key, T defaultValue) {
        return getValue(properties, key, defaultValue, (Class) defaultValue.getClass());
    }

    /**
     * Returns value of a specified property. If the property is not set or the real value type is not compatible with
     * the specified value type, returns defaultValue.
     *
     * @param properties Map of properties to get the property value from.
     * @param key Name of the property.
     * @param defaultValue Default value of the property.
     * @param type Type to retrieve the value as.
     * @param  Type of the property value.
     * @return Value of the property or null.
     */
    public static  T getValue(Map properties, String key, T defaultValue, Class type) {
        T value = getValue(properties, key, type);
        if (value == null) {
            value = defaultValue;
        }
        return value;
    }

    /**
     * Returns value of a specified property. If the property is not set or the real value type is not compatible with
     * the specified value type, returns null.
     *
     * @param properties Map of properties to get the property value from.
     * @param key Name of the property.
     * @param type Type to retrieve the value as.
     * @param  Type of the property value.
     * @return Value of the property or null.
     */
    public static  T getValue(Map properties, String key, Class type) {
        Object value = properties.get(key);

        if (value == null) {
            return null;
        }

        if (!type.isInstance(value)) {
            // TODO: Move string value readers from server to common and utilize them here
            final Constructor constructor = ReflectionHelper.getStringConstructor(type);
            if (constructor != null) {
                try {
                    return type.cast(constructor.newInstance(value));
                } catch (Exception e) {
                    // calling the constructor wasn't successful - ignore and try valueOf()
                }
            }

            final Method valueOf = ReflectionHelper.getValueOfStringMethod(type);
            if (valueOf != null) {
                try {
                    return type.cast(valueOf.invoke(null, value));
                } catch (Exception e) {
                    // calling valueOf wasn't successful
                }
            }

            // at this point we don't know what to return -> return null
            // TODO: should also log warning
            return null;
        }

        return type.cast(value);
    }
}