/**
 * OSHI (https://github.com/oshi/oshi)
 *
 * Copyright (c) 2010 - 2019 The OSHI Project Team:
 * https://github.com/oshi/oshi/graphs/contributors
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */
package oshi.hardware.platform.windows;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.sun.jna.platform.win32.Kernel32; // NOSONAR squid:S1191
import com.sun.jna.platform.win32.Psapi;
import com.sun.jna.platform.win32.Psapi.PERFORMANCE_INFORMATION;

import oshi.hardware.VirtualMemory;
import oshi.hardware.common.AbstractGlobalMemory;

/**
 * Memory obtained by Performance Info.
 */
public class WindowsGlobalMemory extends AbstractGlobalMemory {

    private static final long serialVersionUID = 1L;

    private static final Logger LOG = LoggerFactory.getLogger(WindowsGlobalMemory.class);

    /**
     * {@inheritDoc}
     */
    @Override
    public VirtualMemory getVirtualMemory() {
        if (this.virtualMemory == null) {
            this.virtualMemory = new WindowsVirtualMemory();
        }
        return null;
    }

    /**
     * Update the performance information no more frequently than every 100ms
     */
    @Override
    public void updateAttributes() {
        PERFORMANCE_INFORMATION perfInfo = new PERFORMANCE_INFORMATION();
        if (!Psapi.INSTANCE.GetPerformanceInfo(perfInfo, perfInfo.size())) {
            LOG.error("Failed to get Performance Info. Error code: {}", Kernel32.INSTANCE.GetLastError());
            return;
        }
        this.pageSize = perfInfo.PageSize.longValue();
        this.memAvailable = this.pageSize * perfInfo.PhysicalAvailable.longValue();
        this.memTotal = this.pageSize * perfInfo.PhysicalTotal.longValue();
    }
}

/**
 * OSHI (https://github.com/oshi/oshi)
 *
 * Copyright (c) 2010 - 2019 The OSHI Project Team:
 * https://github.com/oshi/oshi/graphs/contributors
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */
package oshi.hardware.platform.windows;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.sun.jna.platform.win32.Kernel32; // NOSONAR squid:S1191
import com.sun.jna.platform.win32.Psapi;
import com.sun.jna.platform.win32.Psapi.PERFORMANCE_INFORMATION;

import oshi.hardware.VirtualMemory;
import oshi.hardware.common.AbstractGlobalMemory;

/**
 * Memory obtained by Performance Info.
 */
public class WindowsGlobalMemory extends AbstractGlobalMemory {

    private static final long serialVersionUID = 1L;

    private static final Logger LOG = LoggerFactory.getLogger(WindowsGlobalMemory.class);

    /**
     * {@inheritDoc}
     */
    @Override
    public VirtualMemory getVirtualMemory() {
        if (this.virtualMemory == null) {
            this.virtualMemory = new WindowsVirtualMemory();
        }
        return this.virtualMemory;
    }

    /**
     * Update the performance information no more frequently than every 100ms
     */
    @Override
    public void updateAttributes() {
        PERFORMANCE_INFORMATION perfInfo = new PERFORMANCE_INFORMATION();
        if (!Psapi.INSTANCE.GetPerformanceInfo(perfInfo, perfInfo.size())) {
            LOG.error("Failed to get Performance Info. Error code: {}", Kernel32.INSTANCE.GetLastError());
            return;
        }
        this.pageSize = perfInfo.PageSize.longValue();
        this.memAvailable = this.pageSize * perfInfo.PhysicalAvailable.longValue();
        this.memTotal = this.pageSize * perfInfo.PhysicalTotal.longValue();
    }
}

Return the object, not null!