GridTestPrintStreamFactory.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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 org.apache.ignite.internal.util.test;

import java.io.PrintStream;

/**
 * Factory that allow to acquire/release Print Stream for test logging.
 */
public final class GridTestPrintStreamFactory {
    /** */
    private static final PrintStream sysOut = System.out;

    /** */
    private static final PrintStream sysErr = System.err;

    /** */
    private static GridTestPrintStream testOut;

    /** */
    private static GridTestPrintStream testErr;

    /** */
    private static long outCnt = 0;

    /** */
    private static long errCnt = 0;

    /**
     * Enforces singleton.
     */
    private GridTestPrintStreamFactory() {
        // No-op.
    }

    /**
     * Gets original standard out.
     *
     * @return Original standard out.
     */
    public static synchronized PrintStream getStdOut() {
        return sysOut;
    }

    /**
     * Gets original standard error.
     *
     * @return Original standard error.
     */
    public static synchronized PrintStream getStdErr() {
        return sysErr;
    }

    /**
     * Acquires output stream for logging tests.
     *
     * @return Junit out print stream.
     */
    public static synchronized GridTestPrintStream acquireOut() {
        // Lazy initialization is required here to ensure that parent
        // thread group is picked off correctly by implementation.
        if (testOut == null)
            testOut = new GridTestPrintStream(sysOut);

        if (outCnt == 0)
            System.setOut(testOut);

        outCnt++;

        return testOut;
    }

    /**
     * Acquires output stream for logging errors in tests.
     *
     * @return Junit error print stream.
     */
    public static synchronized GridTestPrintStream acquireErr() {
        // Lazy initialization is required here to ensure that parent
        // thread group is picked off correctly by implementation.
        if (testErr == null)
            testErr = new GridTestPrintStream(sysErr);

        if (errCnt == 0)
            System.setErr(testErr);

        errCnt++;

        return testErr;
    }

    /**
     * Releases standard out. If there are no more acquired standard outs,
     * then it is reset to its original value.
     */
    public static synchronized void releaseOut() {
        outCnt--;

        if (outCnt == 0)
            System.setOut(sysOut);
    }

    /**
     * Releases standard error. If there are no more acquired standard errors,
     * then it is reset to its original value.
     */
    public static synchronized void releaseErr() {
        errCnt--;

        if (errCnt == 0)
            System.setErr(sysErr);
    }
}