/*
 * This is free and unencumbered software released into the public domain.
 *
 * Anyone is free to copy, modify, publish, use, compile, sell, or
 * distribute this software, either in source code form or as a compiled
 * binary, for any purpose, commercial or non-commercial, and by any
 * means.
 *
 * In jurisdictions that recognize copyright laws, the author or authors
 * of this software dedicate any and all copyright interest in the
 * software to the public domain. We make this dedication for the benefit
 * of the public at large and to the detriment of our heirs and
 * successors. We intend this dedication to be an overt act of
 * relinquishment in perpetuity of all present and future rights to this
 * software under copyright law.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
 * IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR
 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 * OTHER DEALINGS IN THE SOFTWARE.
 *
 * For more information, please refer to <http://unlicense.org/>
 */
package jxtn.core.unix;

/**
 * Out/Ref reference
 *
 * @author aqd
 * @param <T> referenced value type
 */
public final class Out<T> {

    private boolean assigned;
    private T value;

    public T get() {
        if (!this.assigned) {
            throw new IllegalStateException("not assigned");
        }
        return this.value;
    }

    public void set(T value) {
        if (this.assigned) {
            throw new IllegalStateException("already assigned");
        }
        this.value = value;
        this.assigned = true;
    }

    @Override
    @SuppressWarnings("unchecked")
    public boolean equals(Object obj) {
        if (obj == this) {
            return true;
        }
        if (obj == null || this.getClass() != obj.getClass()) {
            return false;
        }
        return this.equals((Out<T>) obj);
    }

    public boolean equals(Out<T> other) {
        if (other == this) {
            return true;
        }
        if (other == null) {
            return false;
        }
        if (this.value == null) {
            return other.value == null;
        } else {
            return this.value.equals(other.value);
        }
    }

    @Override
    public int hashCode() {
        return this.value == null ? 0 : this.value.hashCode();
    }

    @Override
    public String toString() {
        return "out[" + this.value + "]";
    }

}