/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.commons.functor;

/**
 * Functor marker interface.  All provided functor interfaces extend this interface.
 * <p>
 * Implementors are encouraged but not required to make their functors
 * {@link java.io.Serializable Serializable}.
 * </p>
 *
 * @since 1.0
 * @version $Revision$ $Date$
 */
public interface Functor {

    /**
     * Returns a human readable description of this functor.
     * Implementators are strongly encouraged but not
     * strictly required to override the default {@link Object}
     * implementation of this method.
     *
     * @return a human readable description of this functor
     */
    String toString();

    /**
     * Returns a hash code for this functor adhering to the
     * general {@link Object#hashCode Object.hashCode} contract.
     * Implementators are strongly encouraged but not
     * strictly required to override the default {@link Object}
     * implementation of this method.
     *
     * @see #equals
     * @return a hash code for this functor
     */
    int hashCode();

    /**
     * Indicates whether some other object is &quot;equal to&quot;
     * this functor.  This method must adhere to
     * general {@link Object#equals Object.equals} contract.
     * Additionally, this method can return
     * <tt>true</tt> <i>only</i> if the specified Object implements
     * the same functor interface and is known to produce the same
     * results and/or side-effects for the same arguments (if any).
     * <p>
     * While implementators are strongly encouraged to override
     * the default Object implementation of this method,
     * note that the default Object implementation
     * does in fact adhere to the functor <code>equals</code> contract.
     * </p>
     * @param that the object to compare this functor to
     * @see #hashCode
     * @return <code>true</code> iff the given object implements
     *         this functor interface, and is known to produce the same
     *         results and/or side-effects for the same arguments
     *         (if any).
     */
    boolean equals(Object that);
}

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.commons.functor;

/**
 * Functor marker interface.  All provided functor interfaces extend this interface.
 * <p>
 * While not strictly required,
 * it is <em>encouraged</em> that functor implementations:
 * <ul>
 *   <li>Implement {@link java.io.Serializable Serializable}</li>
 *   <li>Override {@link java.lang.Object#equals(java.lang.Object)}</li>
 *   <li>Override {@link java.lang.Object#hashCode()}</li>
 *   <li>Override {@link java.lang.Object#toString()}</li>
 * </ul>
 * </p>
 *
 * @since 1.0
 * @version $Revision$ $Date$
 */
public interface Functor {
}

Remove method definitions from oacf.Functor interface