org.eclipse.gyrex.server.internal.opsmode.OpsMode.java Source code

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Here is the source code for org.eclipse.gyrex.server.internal.opsmode.OpsMode.java

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/*******************************************************************************
 * Copyright (c) 2010, 2012 AGETO Service GmbH and others.
 * All rights reserved.
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v1.0 which accompanies this distribution,
 * and is available at http://www.eclipse.org/legal/epl-v10.html.
 *
 * Contributors:
 *     Gunnar Wagenknecht - initial API and implementation
 *******************************************************************************/
package org.eclipse.gyrex.server.internal.opsmode;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.concurrent.atomic.AtomicReference;

import org.eclipse.gyrex.boot.internal.BootActivator;
import org.eclipse.gyrex.server.Platform;

import org.apache.commons.io.FileUtils;
import org.apache.commons.io.IOUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Ops mode util.
 */
public class OpsMode {

    /**
     * Returns the instance node id file.
     * 
     * @return the instance node id file
     */
    private static File getInstanceStateFile() {
        return Platform.getStateLocation(BootActivator.getInstance().getBundle()).append(STATE_FILE_NAME).toFile();
    }

    /**
     * property key '<code>gyrex.operation.mode</code>' for
     * <code>config.ini</code>
     */
    String PROPERTY_KEY_OPS_MODE = "gyrex.operation.mode";

    private static final Logger LOG = LoggerFactory.getLogger(OpsMode.class);
    private static final String STATE_FILE_NAME = "operationMode";
    private static final String DEVELOPMENT = "development";
    private static final String PRODUCTION = "production";

    /** operation mode */
    private final AtomicReference<OperationMode> operationMode = new AtomicReference<OperationMode>();

    /**
     * Creates a new instance.
     */
    public OpsMode() {
        initializeOpsMode();
    }

    /**
     * Returns the mode.
     * 
     * @return the mode (defaults to {@link OperationMode#DEVELOPMENT} if not
     *         {@link #isSet() set})
     */
    public OperationMode getMode() {
        final OperationMode mode = operationMode.get();
        if (null != mode) {
            return mode;
        }
        return OperationMode.DEVELOPMENT;
    }

    /**
     * Initialize the configuration mode.
     * 
     * @param context
     */
    private void initializeOpsMode() {
        // read instance state
        String mode = readInstanceState();

        // fallback to config.ini property
        if (null == mode) {
            mode = BootActivator.getInstance().getContext().getProperty(PROPERTY_KEY_OPS_MODE);

            // persist state
            if (null != mode) {
                persistInstanceState(OperationMode.fromString(mode));
            }
        }

        // initialize
        if (null != mode) {
            operationMode.compareAndSet(null, OperationMode.fromString(mode));
        }
    }

    /**
     * Indicates if the operation mode is set (explicitly initialized).
     * 
     * @return <code>true</code> if the operation mode is set,
     *         <code>false</code> otherwise
     */
    public boolean isSet() {
        return null != operationMode.get();
    }

    /**
     * Writes the instance state
     * 
     * @param mode
     */
    private void persistInstanceState(final OperationMode mode) {
        if (null == mode) {
            return;
        }
        final File instanceState = getInstanceStateFile();
        if ((null == instanceState) || instanceState.exists()) {
            // never overwrite existing file
            return;
        }

        // make sure the folders exists
        instanceState.getParentFile().mkdirs();

        FileOutputStream stream = null;
        try {
            stream = FileUtils.openOutputStream(instanceState);
            switch (mode) {
            case PRODUCTION:
                stream.write('p');
                break;

            case DEVELOPMENT:
            default:
                stream.write('d');
                break;
            }
        } catch (final IOException e) {
            LOG.warn("Error saving operation mode. {}", e.getMessage());
        } finally {
            IOUtils.closeQuietly(stream);
        }

    }

    /**
     * Reads the persistent state from the instance.
     * 
     * @return the persistent state
     */
    private String readInstanceState() {
        final File instanceState = getInstanceStateFile();
        if ((null == instanceState) || !instanceState.canRead()) {
            return null;
        }

        FileInputStream stream = null;
        try {
            stream = new FileInputStream(instanceState);
            final int data = stream.read();
            if (data == 'p') {
                return PRODUCTION;
            } else {
                return DEVELOPMENT;
            }
        } catch (final IOException e) {
            // ignore;
            return null;
        } finally {
            if (null != stream) {
                try {
                    stream.close();
                } catch (final IOException e) {
                    // ignore
                }
            }
        }
    }

    public void setMode(final OperationMode mode) {
        if (mode != null) {
            persistInstanceState(mode);
        }
    }
}