com.google.devtools.build.lib.events.EventCollector.java Source code

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Here is the source code for com.google.devtools.build.lib.events.EventCollector.java

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// Copyright 2014 The Bazel Authors. All rights reserved.
//
// 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.google.devtools.build.lib.events;

import com.google.common.base.Predicate;
import com.google.common.collect.ImmutableSet;
import com.google.common.collect.Iterables;

import java.util.ArrayList;
import java.util.Collection;
import java.util.Iterator;
import java.util.Set;

/**
 * An {@link EventHandler} that collects all events it encounters, and makes them available via the
 * {@link Iterable} interface. The collected events contain not just the original event information
 * but also the location context.
 */
public final class EventCollector extends AbstractEventHandler implements Iterable<Event> {
    private final Collection<Event> collected;

    /**
     * This collector will collect all events that match the event mask.
     */
    public EventCollector(Set<EventKind> mask) {
        this(mask, new ArrayList<Event>());
    }

    /**
     * This collector will collect all events.
     */
    public EventCollector() {
        this(EventKind.ALL_EVENTS, new ArrayList<Event>());
    }

    /**
     * This collector will collect all events that match the event mask.
     */
    public EventCollector(EventKind... mask) {
        this(ImmutableSet.copyOf(mask), new ArrayList<Event>());
    }

    /**
     * This collector will save the Event instances in the provided
     * collection.
     */
    public EventCollector(Set<EventKind> mask, Collection<Event> collected) {
        super(mask);
        this.collected = collected;
    }

    /**
     * Implements {@link EventHandler#handle(Event)}.
     */
    @Override
    public synchronized void handle(Event event) {
        if (getEventMask().contains(event.getKind())) {
            collected.add(event);
        }
    }

    /**
     * Returns an iterator over the collected events. This must not be called in a scenario where
     * there may still be concurrent modifications to the collector.
     */
    @Override
    public Iterator<Event> iterator() {
        return collected.iterator();
    }

    /**
     * Returns an iterator over the collected events of the given kind. This must not be called in a
     * scenario where there may still be concurrent modifications to the collector.
     */
    public Iterable<Event> filtered(final EventKind eventKind) {
        return Iterables.filter(collected, new Predicate<Event>() {
            @Override
            public boolean apply(Event event) {
                return event.getKind() == eventKind;
            }
        });
    }

    /**
     * Returns the number of events collected.
     */
    public synchronized int count() {
        return collected.size();
    }

    /*
     * Clears the collected events
     */
    public synchronized void clear() {
        collected.clear();
    }

    @Override
    public synchronized String toString() {
        return "EventCollector: " + Iterables.toString(collected);
    }
}