document/src/main/java/com/yahoo/document/TestAndSetCondition.java


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// Copyright 2016 Yahoo Inc. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
package com.yahoo.document;

import com.google.common.annotations.Beta;

import java.util.Optional;

/**
 * The TestAndSetCondition class represents a test and set condition.
 * A test and set condition is an (optional) string representing a
 * document selection (cf. document selection language), which is used
 * to match a document for test and set. If #isPresent evaluates to false,
 * the condition is not present and matches any document.
 *
 * @author Vegard Sjonfjell
 */
@Beta
public class TestAndSetCondition {
    public static final TestAndSetCondition NOT_PRESENT_CONDITION = new TestAndSetCondition();

    private final String conditionStr;

    public TestAndSetCondition() {
        this("");
    }

    public TestAndSetCondition(String conditionStr) {
        this.conditionStr = conditionStr;
    }

    public String getSelection() { return conditionStr; }

    public boolean isPresent() { return !conditionStr.isEmpty(); }

    /**
     * Maps and optional test and set conditiong string to a TestAndSetCondition.
     * If the condition string is not present, a "not present" condition is returned
     * @param conditionString test and set conditiong string (document selection)
     * @return a TestAndSetCondition representing the condition string or a "not present" condition
     */
    public static TestAndSetCondition fromConditionString(Optional<String> conditionString) {
        return conditionString
                .map(TestAndSetCondition::new)
                .orElse(TestAndSetCondition.NOT_PRESENT_CONDITION);
    }
}