org.haiku.haikudepotserver.support.cayenne.ExpressionHelper.java Source code

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Here is the source code for org.haiku.haikudepotserver.support.cayenne.ExpressionHelper.java

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/*
 * Copyright 2018, Andrew Lindesay
 * Distributed under the terms of the MIT License.
 */

package org.haiku.haikudepotserver.support.cayenne;

import com.google.common.base.Preconditions;
import com.google.common.collect.ImmutableList;
import org.apache.cayenne.exp.Expression;
import org.apache.cayenne.exp.ExpressionFactory;
import org.haiku.haikudepotserver.dataobjects.PkgVersion;
import org.haiku.haikudepotserver.support.VersionCoordinates;

import java.util.Collection;

public class ExpressionHelper {

    public static Expression toExpression(VersionCoordinates coordinates) {
        return toExpression(coordinates, null);
    }

    private static String prefixKey(String prefix, String key) {
        if (null == prefix) {
            return key;
        }

        return prefix + "." + key;
    }

    /**
     * <p>This method will produce an expression that can be used in a Cayenne query.</p>
     */

    public static Expression toExpression(VersionCoordinates coordinates, String prefix) {
        Preconditions.checkNotNull(coordinates);
        Expression majorE = ExpressionFactory.matchExp(prefixKey(prefix, PkgVersion.MAJOR.getName()),
                coordinates.getMajor());
        Expression minorE = ExpressionFactory.matchExp(prefixKey(prefix, PkgVersion.MINOR.getName()),
                coordinates.getMinor());
        Expression microE = ExpressionFactory.matchExp(prefixKey(prefix, PkgVersion.MICRO.getName()),
                coordinates.getMicro());
        Expression preReleaseE = ExpressionFactory.matchExp(prefixKey(prefix, PkgVersion.PRE_RELEASE.getName()),
                coordinates.getPreRelease());
        Expression revisionE = ExpressionFactory.matchExp(prefixKey(prefix, PkgVersion.REVISION.getName()),
                coordinates.getRevision());
        return andAll(ImmutableList.of(majorE, minorE, microE, preReleaseE, revisionE));
    }

    private static Expression andAll(Collection<Expression> expressions) {
        Preconditions.checkNotNull(expressions);
        Expression result = null;

        for (Expression expression : expressions) {
            if (null == result) {
                result = expression;
            } else {
                result = result.andExp(expression);
            }
        }

        return result;
    }

}