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a-base is a library of basic (hence the name) classes, most notably immutable collection classes with copy-on-write operations

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package com.ajjpj.abase.collection;


import java.io.Serializable;


/**
 * This class wraps arbitrary objects, providing customizable equals() and hashCode() behavior based
 *  on an AEquality instance. Calls to equals() or hashCode() on the wrapper are delegated
 *  to the corresponding calls on the AEquality instance. 
 *
 * This is a rather low-level class that is primarily useful for infrstructure code. If you do not understand its usefulness, you
 *  probably do not need it.
 *
 * @author arno
 */
public class AEqualsWrapper implements Serializable { //TODO junit
    final AEquality equality;
    public final T value;

    public AEqualsWrapper(AEquality equality, T value) {
        this.equality = equality;
        this.value = value;
    }

    @SuppressWarnings("EqualsWhichDoesntCheckParameterClass")
    @Override public boolean equals(Object obj) {
        return equality.equals(value, ((AEqualsWrapper)obj).value);
    }

    @Override public int hashCode() {
        return equality.hashCode(value);
    }

    @Override
    public String toString() {
        return value.toString();
    }
}