com.liveramp.megadesk.base.transaction.BaseVariableDependency.java Source code

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Here is the source code for com.liveramp.megadesk.base.transaction.BaseVariableDependency.java

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/**
 *  Copyright 2014 LiveRamp
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */

package com.liveramp.megadesk.base.transaction;

import org.apache.commons.lang.builder.CompareToBuilder;

import com.liveramp.megadesk.core.state.Lock;
import com.liveramp.megadesk.core.state.Variable;
import com.liveramp.megadesk.core.transaction.DependencyType;
import com.liveramp.megadesk.core.transaction.VariableDependency;

public class BaseVariableDependency<VALUE> implements VariableDependency<VALUE> {

    private final Variable<VALUE> variable;
    private final DependencyType type;

    public BaseVariableDependency(Variable<VALUE> variable, DependencyType type) {
        this.variable = variable;
        this.type = type;
    }

    public static <VALUE> BaseVariableDependency<VALUE> build(Variable<VALUE> variable, DependencyType type) {
        return new BaseVariableDependency<VALUE>(variable, type);
    }

    @Override
    public Variable<VALUE> variable() {
        return variable;
    }

    @Override
    public DependencyType type() {
        return type;
    }

    @Override
    public Lock lock() {
        switch (type) {
        case READ:
            return variable.driver().lock().readLock();
        case WRITE:
            return variable.driver().lock().writeLock();
        default:
            throw new IllegalStateException(); // TODO: message
        }
    }

    @Override
    public int compareTo(VariableDependency<VALUE> o) {
        return new CompareToBuilder().append(variable, o.variable()).toComparison();
    }
}