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Java example source code file (InterceptorList.java)

This example Java source code file (InterceptorList.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

arraylist, class, comparable, corba, duplicatename, interceptor, interceptor_type_client, interceptor_type_ior, interceptor_type_server, interceptorlist, interceptorssystemexception, iterator, num_interceptor_types, reflection, string, util

The InterceptorList.java Java example source code

/*
 * Copyright (c) 2000, 2003, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code 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 General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

package com.sun.corba.se.impl.interceptors;

import org.omg.PortableInterceptor.Interceptor;
import org.omg.PortableInterceptor.ORBInitInfo;
import org.omg.PortableInterceptor.ORBInitInfoPackage.DuplicateName;

import org.omg.CORBA.INTERNAL;

import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;
import java.lang.reflect.Array;

import com.sun.corba.se.impl.logging.InterceptorsSystemException ;

/**
 * Provides a repository of registered Portable Interceptors, organized
 * by type.  This list is designed to be accessed as efficiently as
 * possible during runtime, with the expense of added complexity during
 * initialization and interceptor registration.  The class is designed
 * to easily allow for the addition of new interceptor types.
 */
public class InterceptorList {

    // Interceptor type list.  If additional interceptors are needed,
    // add additional types in numerical order (do not skip numbers),
    // and update NUM_INTERCEPTOR_TYPES and classTypes accordingly.
    // NUM_INTERCEPTOR_TYPES represents the number of interceptor
    // types, so we know how many lists to maintain.
    static final int INTERCEPTOR_TYPE_CLIENT            = 0;
    static final int INTERCEPTOR_TYPE_SERVER            = 1;
    static final int INTERCEPTOR_TYPE_IOR               = 2;

    static final int NUM_INTERCEPTOR_TYPES              = 3;

    // Array of class types for interceptors.  This is used to create the
    // appropriate array type for each interceptor type.  These must
    // match the indices of the constants declared above.
    static final Class[] classTypes = {
        org.omg.PortableInterceptor.ClientRequestInterceptor.class,
        org.omg.PortableInterceptor.ServerRequestInterceptor.class,
        org.omg.PortableInterceptor.IORInterceptor.class
    };

    // True if no further interceptors may be registered with this list.
    private boolean locked = false;
    private InterceptorsSystemException wrapper ;

    // List of interceptors currently registered.  There are
    // NUM_INTERCEPTOR_TYPES lists of registered interceptors.
    // For example, interceptors[INTERCEPTOR_TYPE_CLIENT] contains an array
    // of objects of type ClientRequestInterceptor.
    private Interceptor[][] interceptors =
        new Interceptor[NUM_INTERCEPTOR_TYPES][];

    /**
     * Creates a new Interceptor List.  Constructor is package scope so
     * only the ORB can create it.
     */
    InterceptorList( InterceptorsSystemException wrapper ) {
        this.wrapper = wrapper ;
        // Create empty interceptors arrays for each type:
        initInterceptorArrays();
    }

    /**
     * Registers an interceptor of the given type into the interceptor list.
     * The type is one of:
     * <ul>
     *   <li>INTERCEPTOR_TYPE_CLIENT - ClientRequestInterceptor
     *   <li>INTERCEPTOR_TYPE_SERVER - ServerRequestInterceptor
     *   <li>INTERCEPTOR_TYPE_IOR - IORInterceptor
     * </ul>
     *
     * @exception DuplicateName Thrown if an interceptor of the given
     *     name already exists for the given type.
     */
    void register_interceptor( Interceptor interceptor, int type )
        throws DuplicateName
    {
        // If locked, deny any further addition of interceptors.
        if( locked ) {
            throw wrapper.interceptorListLocked() ;
        }

        // Cache interceptor name:
        String interceptorName = interceptor.name();
        boolean anonymous = interceptorName.equals( "" );
        boolean foundDuplicate = false;
        Interceptor[] interceptorList = interceptors[type];

        // If this is not an anonymous interceptor,
        // search for an interceptor of the same name in this category:
        if( !anonymous ) {
            int size = interceptorList.length;

            // An O(n) search will suffice because register_interceptor is not
            // likely to be called often.
            for( int i = 0; i < size; i++ ) {
                Interceptor in = (Interceptor)interceptorList[i];
                if( in.name().equals( interceptorName ) ) {
                    foundDuplicate = true;
                    break;
                }
            }
        }

        if( !foundDuplicate ) {
            growInterceptorArray( type );
            interceptors[type][interceptors[type].length-1] = interceptor;
        }
        else {
            throw new DuplicateName( interceptorName );
        }
    }

    /**
     * Locks this interceptor list so that no more interceptors may be
     * registered.  This method is called after all interceptors are
     * registered for security reasons.
     */
    void lock() {
        locked = true;
    }

    /**
     * Retrieves an array of interceptors of the given type.  For efficiency,
     * the type parameter is assumed to be valid.
     */
    Interceptor[] getInterceptors( int type ) {
        return interceptors[type];
    }

    /**
     * Returns true if there is at least one interceptor of the given type,
     * or false if not.
     */
    boolean hasInterceptorsOfType( int type ) {
        return interceptors[type].length > 0;
    }

    /**
     * Initializes all interceptors arrays to zero-length arrays of the
     * correct type, based on the classTypes list.
     */
    private void initInterceptorArrays() {
        for( int type = 0; type < NUM_INTERCEPTOR_TYPES; type++ ) {
            Class classType = classTypes[type];

            // Create a zero-length array for each type:
            interceptors[type] =
                (Interceptor[])Array.newInstance( classType, 0 );
        }
    }

    /**
     * Grows the given interceptor array by one:
     */
    private void growInterceptorArray( int type ) {
        Class classType = classTypes[type];
        int currentLength = interceptors[type].length;
        Interceptor[] replacementArray;

        // Create new array to replace the old one.  The new array will be
        // one element larger but have the same type as the old one.
        replacementArray = (Interceptor[])
            Array.newInstance( classType, currentLength + 1 );
        System.arraycopy( interceptors[type], 0,
                          replacementArray, 0, currentLength );
        interceptors[type] = replacementArray;
    }

    /**
     * Destroys all interceptors in this list by invoking their destroy()
     * method.
     */
    void destroyAll() {
        int numTypes = interceptors.length;

        for( int i = 0; i < numTypes; i++ ) {
            int numInterceptors = interceptors[i].length;
            for( int j = 0; j < numInterceptors; j++ ) {
                interceptors[i][j].destroy();
            }
        }
    }

    /**
     * Sort interceptors.
     */
    void sortInterceptors() {
        List sorted = null;
        List unsorted = null;

        int numTypes = interceptors.length;

        for( int i = 0; i < numTypes; i++ ) {
            int numInterceptors = interceptors[i].length;
            if (numInterceptors > 0) {
                // Get fresh sorting bins for each non empty type.
                sorted = new ArrayList(); // not synchronized like we want.
                unsorted = new ArrayList();
            }
            for( int j = 0; j < numInterceptors; j++ ) {
                Interceptor interceptor = interceptors[i][j];
                if (interceptor instanceof Comparable) {
                    sorted.add(interceptor);
                } else {
                    unsorted.add(interceptor);
                }
            }
            if (numInterceptors > 0 && sorted.size() > 0) {
                // Let the RuntimeExceptions thrown by sort
                // (i.e., ClassCastException and UnsupportedOperationException)
                // flow back to the user.
                Collections.sort(sorted);
                Iterator sortedIterator = sorted.iterator();
                Iterator unsortedIterator = unsorted.iterator();
                for( int j = 0; j < numInterceptors; j++ ) {
                    if (sortedIterator.hasNext()) {
                        interceptors[i][j] =
                            (Interceptor) sortedIterator.next();
                    } else if (unsortedIterator.hasNext()) {
                        interceptors[i][j] =
                            (Interceptor) unsortedIterator.next();
                    } else {
                        throw wrapper.sortSizeMismatch() ;
                    }
                }
            }
        }
    }
}

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