org.prebake.core.ImmutableGlobSet.java Source code

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Here is the source code for org.prebake.core.ImmutableGlobSet.java

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// Copyright 2010, Mike Samuel
//
// 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 org.prebake.core;

import java.util.Collections;
import java.util.Iterator;

import com.google.common.collect.ImmutableList;

/**
 * An immutable {@link GlobSet}.
 *
 * @author Mike Samuel <mikesamuel@gmail.com>
 */
public final class ImmutableGlobSet extends GlobSet {
    private ImmutableGlobSet(GlobSet gset) {
        super(gset);
    }

    private ImmutableGlobSet(Iterable<? extends Glob> globs) {
        snapshot = ImmutableList.copyOf(globs); // Preserve iteration order.
        for (Glob g : snapshot) {
            this.add(g);
        }
    }

    public static ImmutableGlobSet copyOf(GlobSet gset) {
        if (gset instanceof ImmutableGlobSet) {
            return (ImmutableGlobSet) gset;
        }
        return new ImmutableGlobSet(gset);
    }

    public static ImmutableGlobSet of(Iterable<? extends Glob> globs) {
        return new ImmutableGlobSet(globs);
    }

    public static ImmutableGlobSet empty() {
        return of(Collections.<Glob>emptySet());
    }

    private ImmutableList<Glob> snapshot;

    @Override
    public Iterator<Glob> iterator() {
        if (snapshot == null) {
            snapshot = snapshot();
        }
        return snapshot.iterator();
    }

    @Override
    public boolean equals(Object o) {
        if (o == null || o.getClass() != getClass()) {
            return false;
        }
        if (o == this) {
            return true;
        }
        ImmutableGlobSet that = (ImmutableGlobSet) o;
        Iterator<Glob> thisIt = this.iterator(), thatIt = that.iterator();
        while (thisIt.hasNext()) {
            if (!thatIt.hasNext()) {
                return false;
            }
            if (!thisIt.next().equals(thatIt.next())) {
                return false;
            }
        }
        return !thatIt.hasNext();
    }

    private int hc;

    @Override
    public int hashCode() {
        if (hc == 0) {
            int hc = 0;
            Iterator<Glob> thisIt = this.iterator();
            while (thisIt.hasNext()) {
                hc = hc * 31 + thisIt.next().hashCode();
            }
            if (hc == 0) {
                hc = 1;
            }
            this.hc = hc;
        }
        return hc;
    }
}