MethodIdentificationSupport.java

/**
 * OpenSpotLight - Open Source IT Governance Platform
 *
 * Copyright (c) 2009, CARAVELATECH CONSULTORIA E TECNOLOGIA EM INFORMATICA LTDA
 * or third-party contributors as indicated by the @author tags or express
 * copyright attribution statements applied by the authors.  All third-party
 * contributions are distributed under license by CARAVELATECH CONSULTORIA E
 * TECNOLOGIA EM INFORMATICA LTDA.
 *
 * This copyrighted material is made available to anyone wishing to use, modify,
 * copy, or redistribute it subject to the terms and conditions of the GNU
 * Lesser General Public License, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 *
 * See the GNU Lesser General Public License  for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this distribution; if not, write to:
 * Free Software Foundation, Inc.
 * 51 Franklin Street, Fifth Floor
 * Boston, MA  02110-1301  USA
 *
 ***********************************************************************
 * OpenSpotLight - Plataforma de Governança de TI de Código Aberto
 *
 * Direitos Autorais Reservados (c) 2009, CARAVELATECH CONSULTORIA E TECNOLOGIA
 * EM INFORMATICA LTDA ou como contribuidores terceiros indicados pela etiqueta
 * @author ou por expressa atribuição de direito autoral declarada e atribuída pelo autor.
 * Todas as contribuições de terceiros estão distribuídas sob licença da
 * CARAVELATECH CONSULTORIA E TECNOLOGIA EM INFORMATICA LTDA.
 *
 * Este programa é software livre; você pode redistribuí-lo e/ou modificá-lo sob os
 * termos da Licença Pública Geral Menor do GNU conforme publicada pela Free Software
 * Foundation.
 *
 * Este programa é distribuído na expectativa de que seja útil, porém, SEM NENHUMA
 * GARANTIA; nem mesmo a garantia implícita de COMERCIABILIDADE OU ADEQUAÇÃO A UMA
 * FINALIDADE ESPECÍFICA. Consulte a Licença Pública Geral Menor do GNU para mais detalhes.
 *
 * Você deve ter recebido uma cópia da Licença Pública Geral Menor do GNU junto com este
 * programa; se não, escreva para:
 * Free Software Foundation, Inc.
 * 51 Franklin Street, Fifth Floor
 * Boston, MA  02110-1301  USA
 */

package org.openspotlight.common.util.reflection;

import java.lang.reflect.Method;

/**
 * This class contains some useful static methods and inner classes to be used to identify a method or a method with specific
 * parameters. This class should be used only on API stuffs.
 * 
 * @author feu
 */
public class MethodIdentificationSupport {

    /**
     * Parameter key to be used as a key inside the cache map for method invocation.
     * 
     * @author feu
     */
    public static final class MethodWithParametersKey {

        /** The hashcode. */
        private final int      hashcode;

        /** The key. */
        private final String   key;

        /** The parameters. */
        private final Object[] parameters;

        /**
         * Constructor with final fields.
         * 
         * @param key the key
         * @param parameters the parameters
         */
        public MethodWithParametersKey(
                                        final String key, final Object... parameters) {
            if (parameters == null) { throw new IllegalArgumentException(); }
            if (key == null) { throw new IllegalArgumentException(); }
            if (key.length() == 0) { throw new IllegalArgumentException(); }
            this.key = key;
            this.parameters = parameters;
            int hashing = 7;
            hashing = 31 * hashing + key.hashCode();
            for (final Object parameter: parameters) {
                hashing = 31 * hashing + (parameter == null ? 0 : parameter.hashCode());
            }
            hashcode = hashing;
        }

        @Override
        public boolean equals(final Object obj) {
            if (obj == this) { return true; }
            if (!(obj instanceof MethodWithParametersKey)) { return false; }
            final MethodWithParametersKey that = (MethodWithParametersKey) obj;
            if (that.parameters.length != parameters.length) { return false; }
            if (!isEquals(key, that.key)) { return false; }
            for (int i = 0, size = parameters.length; i < size; i++) {
                if (!isEquals(parameters[i], that.parameters[i])) { return false; }
            }
            return true;
        }

        @Override
        public int hashCode() {
            return hashcode;
        }

    }

    /**
     * This enum specifies the behavior applied on the new object. It should behave like a wrapped object when the default
     * constructor is used, or like enhanced object when the non default constructor is called.
     */
    public static enum UseEnhanced {

        /** use enhanced. */
        USE_ENHANCED,

        /** use wrapped. */
        USE_WRAPPED
    }

    /**
     * Checks if is equals in a null pointer safe way.
     * 
     * @param o1 the o1
     * @param o2 the o2
     * @return true, if is equals
     */
    static boolean isEquals(final Object o1,
                             final Object o2) {
        if (o1 == o2) { return true; }
        if (o1 == null) { return false; }
        if (o2 == null) { return false; }
        return o1.equals(o2);
    }

    /**
     * Gets the method unique name.
     * 
     * @param arg1 the arg1
     * @return the method unique name
     */
    public static String getMethodUniqueName(final Method arg1) {
        final Class<?>[] parameterTypes = arg1.getParameterTypes();
        final StringBuilder nameBuff = new StringBuilder();
        nameBuff.append(arg1.getName());
        nameBuff.append(':');
        nameBuff.append(arg1.getReturnType().getName());
        nameBuff.append('/');
        for (int i = 0, size = parameterTypes.length; i < size; i++) {
            nameBuff.append(parameterTypes[i].getName());
            if (i != size - 1) {
                nameBuff.append(',');
            }
        }
        return nameBuff.toString();
    }

}