Constants.java

/*
 * Licensed to Elasticsearch under one or more contributor
 * license agreements. See the NOTICE file distributed with
 * this work for additional information regarding copyright
 * ownership. Elasticsearch 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.elasticsearch.hadoop.util;

import java.lang.reflect.Field;
import java.util.Collections;

// taken from Apache Lucene
public abstract class Constants {

    public static final String OS_ARCH = System.getProperty("os.arch");

    public static final boolean JRE_IS_MINIMUM_JAVA7;
    public static final boolean JRE_IS_MINIMUM_JAVA8;

    /** True if running on a 64bit JVM */
    public static final boolean JRE_IS_64BIT;

    static {
        boolean is64Bit = false;
        try {
            final Class<?> unsafeClass = Class.forName("sun.misc.Unsafe");
            final Field unsafeField = unsafeClass.getDeclaredField("theUnsafe");
            unsafeField.setAccessible(true);
            final Object unsafe = unsafeField.get(null);
            final int addressSize = ((Number) unsafeClass.getMethod("addressSize").invoke(unsafe)).intValue();
            //System.out.println("Address size: " + addressSize);
            is64Bit = addressSize >= 8;
        } catch (Exception e) {
            final String x = System.getProperty("sun.arch.data.model");
            if (x != null) {
                is64Bit = x.indexOf("64") != -1;
            }
            else {
                if (OS_ARCH != null && OS_ARCH.indexOf("64") != -1) {
                    is64Bit = true;
                }
                else {
                    is64Bit = false;
                }
            }
        }
        JRE_IS_64BIT = is64Bit;

        // this method only exists in Java 7:
        boolean v7 = true;
        try {
            Throwable.class.getMethod("getSuppressed");
        } catch (NoSuchMethodException nsme) {
            v7 = false;
        }
        JRE_IS_MINIMUM_JAVA7 = v7;

        if (JRE_IS_MINIMUM_JAVA7) {
            // this method only exists in Java 8:
            boolean v8 = true;
            try {
                Collections.class.getMethod("emptySortedSet");
            } catch (NoSuchMethodException nsme) {
                v8 = false;
            }
            JRE_IS_MINIMUM_JAVA8 = v8;
        }
        else {
            JRE_IS_MINIMUM_JAVA8 = false;
        }
    }
}