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A JSR330 style dependency injection solution

There is a newer version: 1.13.2

package org.osgl.inject;

import org.osgl.$;

/**
 * `KeyExtractor` can be used to extract or derive "key" from
 * a value data. The result "key" can be used to index the value
 * in a {@link java.util.Map} data structure.
 * 
 * A general contract implementation must obey is
 * different value must generate different key
 *
 * @param  generic type of the key
 * @param  generic type of the value
 */
public interface KeyExtractor {
    /**
     * Get the key of data
     *
     * @param hint optional, a string value provides hint to extract key
     * @param data the value data
     * @return the key of the data
     */
    K keyOf(String hint, V data);

    class PropertyExtractor implements KeyExtractor {
        @Override
        public Object keyOf(String hint, Object data) {
            return $.getProperty(data, hint);
        }
    }
}