edu.cornell.mannlib.vitro.webapp.config.RevisionInfoBean.java Source code

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Here is the source code for edu.cornell.mannlib.vitro.webapp.config.RevisionInfoBean.java

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/* $This file is distributed under the terms of the license in /doc/license.txt$ */

package edu.cornell.mannlib.vitro.webapp.config;

import java.util.Date;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.List;

import javax.servlet.ServletContext;
import javax.servlet.http.HttpSession;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import com.ibm.icu.text.SimpleDateFormat;

/**
 * Information about the provenance of this application: release, revision
 * level, build date, etc.
 * 
 * Except for the build date, the information is stored for all levels of the
 * application. So an instance of NIHVIVO might read:
 * 
 * date: 2010-11-09 12:15:44
 * 
 * level: vitro-core, trunk, 1234:1236M
 * 
 * level: vivo, branch rel_1.1_maint, 798
 * 
 * Note that the levels should be listed from inner to outer.
 * 
 * Instances of this class are immutable.
 */
public class RevisionInfoBean {
    private static final Log log = LogFactory.getLog(RevisionInfoBean.class);

    /** A dummy bean to use if there is no real one. */
    static final RevisionInfoBean DUMMY_BEAN = new RevisionInfoBean(new Date(0),
            Collections.singleton(LevelRevisionInfo.DUMMY_LEVEL));

    /** The bean is attached to the session by this name. */
    static final String ATTRIBUTE_NAME = RevisionInfoBean.class.getName();

    // ----------------------------------------------------------------------
    // static methods
    // ----------------------------------------------------------------------

    /** Package access: should only be used during setup. */
    static void setBean(ServletContext context, RevisionInfoBean bean) {
        if (bean == null) {
            bean = DUMMY_BEAN;
        }
        context.setAttribute(ATTRIBUTE_NAME, bean);
        log.info(bean);
    }

    public static RevisionInfoBean getBean(HttpSession session) {
        if (session == null) {
            log.warn("Tried to get revision info bean with a null session!");
            return DUMMY_BEAN;
        }

        return getBean(session.getServletContext());
    }

    public static RevisionInfoBean getBean(ServletContext context) {
        if (context == null) {
            log.warn("Tried to get revision info bean from a null context");
            return DUMMY_BEAN;
        }

        Object o = context.getAttribute(ATTRIBUTE_NAME);
        if (o == null) {
            log.warn("Tried to get revision info bean, but didn't find any.");
            return DUMMY_BEAN;
        }

        if (!(o instanceof RevisionInfoBean)) {
            log.error("Tried to get revision info bean, but found an instance of " + o.getClass().getName() + ": "
                    + o);
            return DUMMY_BEAN;
        }

        return (RevisionInfoBean) o;
    }

    public static void removeBean(ServletContext context) {
        context.removeAttribute(ATTRIBUTE_NAME);
    }

    // ----------------------------------------------------------------------
    // the bean
    // ----------------------------------------------------------------------

    private final long buildDate;
    private final List<LevelRevisionInfo> levelInfos;

    RevisionInfoBean(Date buildDate, Collection<LevelRevisionInfo> levelInfos) {
        this.buildDate = buildDate.getTime();
        this.levelInfos = Collections.unmodifiableList(new ArrayList<LevelRevisionInfo>(levelInfos));
    }

    public Date getBuildDate() {
        return new Date(buildDate);
    }

    public List<LevelRevisionInfo> getLevelInfos() {
        return levelInfos;
    }

    public String getReleaseLabel() {
        if (levelInfos.isEmpty()) {
            return LevelRevisionInfo.DUMMY_LEVEL.getRelease();
        }

        int lastIndex = levelInfos.size() - 1;
        LevelRevisionInfo outerLevel = levelInfos.get(lastIndex);
        return outerLevel.getRelease();
    }

    @Override
    public String toString() {
        return "Revision info [build date: " + new SimpleDateFormat().format(new Date(buildDate)) + ", level info: "
                + levelInfos + "]";
    }

    @Override
    public boolean equals(Object obj) {
        if (obj == this) {
            return true;
        }
        if (!(obj instanceof RevisionInfoBean)) {
            return false;
        }
        RevisionInfoBean that = (RevisionInfoBean) obj;
        return (this.buildDate == that.buildDate) && this.levelInfos.equals(that.levelInfos);
    }

    @Override
    public int hashCode() {
        return new Long(buildDate).hashCode() ^ levelInfos.hashCode();
    }

    // ----------------------------------------------------------------------
    // helper class
    // ----------------------------------------------------------------------

    /**
     * Revision info about one level of the application -- e.g. vitro, vivo,
     * vivoCornell, etc.
     */
    public static class LevelRevisionInfo {
        /** A level to use when no actual level can be found. */
        static final LevelRevisionInfo DUMMY_LEVEL = new LevelRevisionInfo("no name", "unknown", "unknown");

        private final String name;
        private final String release;
        private final String revision;

        LevelRevisionInfo(String name, String release, String revision) {
            this.name = name;
            this.release = release;
            this.revision = revision;
        }

        public String getName() {
            return name;
        }

        public String getRelease() {
            return release;
        }

        public String getRevision() {
            return revision;
        }

        @Override
        public String toString() {
            return "[" + name + ", " + release + ", " + revision + "]";
        }

        @Override
        public boolean equals(Object obj) {
            if (obj == this) {
                return true;
            }
            if (!(obj instanceof LevelRevisionInfo)) {
                return false;
            }
            LevelRevisionInfo that = (LevelRevisionInfo) obj;
            return this.name.equals(that.name) && this.release.equals(that.release)
                    && this.revision.equals(that.revision);
        }

        @Override
        public int hashCode() {
            return name.hashCode() ^ release.hashCode() ^ revision.hashCode();
        }

    }

}