Glassfish example source code file (MapUtil.java)

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

Java - Glassfish tags/keywords

class, hashmap, illegalargumentexception, k, k, map, map, object, set, string, string, t, util, v, v

The Glassfish MapUtil.java source code

/*
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
 *
 * Copyright (c) 1997-2010 Oracle and/or its affiliates. All rights reserved.
 *
 * The contents of this file are subject to the terms of either the GNU
 * General Public License Version 2 only ("GPL") or the Common Development
 * and Distribution License("CDDL") (collectively, the "License").  You
 * may not use this file except in compliance with the License.  You can
 * obtain a copy of the License at
 * https://glassfish.dev.java.net/public/CDDL+GPL_1_1.html
 * or packager/legal/LICENSE.txt.  See the License for the specific
 * language governing permissions and limitations under the License.
 *
 * When distributing the software, include this License Header Notice in each
 * file and include the License file at packager/legal/LICENSE.txt.
 *
 * GPL Classpath Exception:
 * Oracle designates this particular file as subject to the "Classpath"
 * exception as provided by Oracle in the GPL Version 2 section of the License
 * file that accompanied this code.
 *
 * Modifications:
 * If applicable, add the following below the License Header, with the fields
 * enclosed by brackets [] replaced by your own identifying information:
 * "Portions Copyright [year] [name of copyright owner]"
 *
 * Contributor(s):
 * If you wish your version of this file to be governed by only the CDDL or
 * only the GPL Version 2, indicate your decision by adding "[Contributor]
 * elects to include this software in this distribution under the [CDDL or GPL
 * Version 2] license."  If you don't indicate a single choice of license, a
 * recipient has the option to distribute your version of this file under
 * either the CDDL, the GPL Version 2 or to extend the choice of license to
 * its licensees as provided above.  However, if you add GPL Version 2 code
 * and therefore, elected the GPL Version 2 license, then the option applies
 * only if the new code is made subject to such option by the copyright
 * holder.
 */

package org.glassfish.admin.amx.util;

import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Properties;
import java.util.Set;

public final class MapUtil
{
    private MapUtil()
    {
        // disallow instantiation
    }

    public static <K, V> V getWithDefault(final Map m, final K key, V defaultValue)
    {
        return m.containsKey(key) ? m.get(key) : defaultValue;
    }

    public static Object[] getKeyObjects(final Map<?, ?> m)
    {
        final Object[] keys = new Object[m.keySet().size()];
        m.keySet().toArray(keys);
        return keys;
    }

    public static String[] getKeyStrings(final Map<?, ?> m)
    {
        return (SetUtil.toSortedStringArray(m.keySet()));
    }

    /** assignable to any map type, keeps things short on the rhs */
    public static <K, V> Map newMap()
    {
        return new HashMap<K, V>();
    }

    /**
    Create a new Map consisting of a single key/value pair.
     */
    public static <V> Map newMap(
            final String key,
            final V value)
    {
        final Map<String, V> m = new HashMap();

        m.put(key, value);

        return (m);
    }

    /**
    Create a new Map consisting of a single key/value pair.
     */
    public static <K, V> Map newMap(
            final Map<K, V> m1,
            final Map<K, V> m2)
    {
        final Map<K, V> m = new HashMap();

        if (m1 != null)
        {
            m.putAll(m1);
        }
        if (m2 != null)
        {
            m.putAll(m2);
        }

        return (m);
    }

    public static <K, V> Map toMap(final Object[] params, final Class keyClass, final Class valueClass)
    {
        final Map<K, V> m = new HashMap();

        for (int i = 0; i < params.length; i += 2)
        {
            final Object key = params[i];
            if (key == null)
            {
                throw new IllegalArgumentException();
            }

            if (!keyClass.isAssignableFrom(key.getClass()))
            {
                throw new IllegalArgumentException("Key of class " + key.getClass().getName() + " not assignable to " + keyClass.getName());
            }

            final Object value = params[i + 1];
            if (value != null && !valueClass.isAssignableFrom(value.getClass()))
            {
                throw new IllegalArgumentException("Value of class " + value.getClass().getName() + " not assignable to " + valueClass.getName());
            }

            m.put(keyClass.cast(key), valueClass.cast(value));
        }
        return m;
    }

    /**
    Create a new Map and insert the specified mappings as found in 'mappings'.
    The even-numbered entries are the keys, and the odd-numbered entries are
    the values.
     */
    public static <T> Map newMap(final T... mappings)
    {
        if ((mappings.length % 2) != 0)
        {
            throw new IllegalArgumentException("mappings must have even length");
        }

        final Map<T, T> m = new HashMap();

        for (int i = 0; i < mappings.length; i += 2)
        {
            m.put(mappings[i], mappings[i + 1]);
        }

        return (m);
    }

    /**
    Create a new Map and insert the specified mappings as found in 'mappings'.
    The even-numbered entries are the keys, and the odd-numbered entries are
    the values.
     */
    public static Map<String, String> newMap(final String... mappings)
    {
        if ((mappings.length % 2) != 0)
        {
            throw new IllegalArgumentException("mappings must have even length");
        }

        final Map<String, String> m = new HashMap();

        for (int i = 0; i < mappings.length; i += 2)
        {
            m.put(mappings[i], mappings[i + 1]);
        }

        return (m);
    }

    /**
    Remove all entries keyed by 'keys'
     */
    public static <T> void removeAll(
            final Map<T, ?> m,
            final T[] keys)
    {
        for (int i = 0; i < keys.length; ++i)
        {
            m.remove(keys[i]);
        }
    }

    public static boolean mapsEqual(
            final Map<?, ?> m1,
            final Map<?, ?> m2)
    {
        if (m1 == m2)
        {
            return (true);
        }

        boolean equal = false;

        if (m1.size() == m2.size() &&
            m1.keySet().equals(m2.keySet()))
        {
            equal = true;

            for (final Object key : m1.keySet())
            {
                final Object value1 = m1.get(key);
                final Object value2 = m2.get(key);

                if (!CompareUtil.objectsEqual(value1, value2))
                {
                    equal = false;
                    break;
                }
            }
        }

        return (equal);
    }

    public static <K, V> Map newMapNoNullValues(final Map m)
    {
        final Map<K, V> result = new HashMap();

        for (final K key : m.keySet())
        {
            final V value = m.get(key);

            if (value != null)
            {
                result.put(key, value);
            }
        }

        return (result);
    }

    public static String toString(final Map<?, ?> m)
    {
        return (toString(m, ","));
    }

    public static String toString(final Map<?, ?> m, final String separator)
    {
        if (m == null)
        {
            return ("null");
        }

        final StringBuffer buf = new StringBuffer();

        final String[] keyStrings = getKeyStrings(m);
        for (final String key : keyStrings)
        {
            final Object value = m.get(key);

            buf.append(key);
            buf.append("=");
            buf.append(StringUtil.toString(value));
            buf.append(separator);
        }
        if (buf.length() != 0)
        {
            // strip trailing separator
            buf.setLength(buf.length() - separator.length());
        }

        return (buf.toString());
    }

    public static <K> Set getNullValueKeys(final Map m)
    {
        final Set<K> s = new HashSet();

        for (final K key : m.keySet())
        {
            if (m.get(key) == null)
            {
                s.add(key);
            }
        }
        return (s);
    }

    public static <K, V> Map toMap(final Properties props, final Class kClass, final Class vClass)
    {
        return TypeCast.checkMap(props, kClass, vClass);
    }

    public static <K> void removeAll(final Map m, final Set s)
    {
        for (final K key : s)
        {
            m.remove(key);
        }
    }

    /**
    @return true if non-null Map and all keys and values are of type java.lang.String
     */
    public static boolean isAllStrings(final Map<?, ?> m)
    {
        return m != null && CollectionUtil.isAllStrings(m.keySet()) &&
               CollectionUtil.isAllStrings(m.values());
    }

    /**
    Convert an arbitrary Map to one whose keys and values
    are both of type String.
     */
    public static Map<String, String> toStringStringMap(final Map m)
    {
        if (m == null)
        {
            return null;
        }

        Map<String, String> result = null;

        if (isAllStrings(m))
        {
            result = TypeCast.asMap(m);
        }
        else
        {
            result = new HashMap<String, String>();

            for (final Object key : m.keySet())
            {
                final Object value = m.get(key);

                if ((key instanceof String) && (value instanceof String))
                {
                    result.put((String) key, (String) value);
                }
                else
                {
                    result.put("" + key, "" + value);
                }
            }
        }

        return result;
    }

}