com.facebook.buck.rules.AbstractSourcePath.java Source code

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Here is the source code for com.facebook.buck.rules.AbstractSourcePath.java

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/*
 * Copyright 2013-present Facebook, Inc.
 *
 * 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.facebook.buck.rules;

import com.google.common.base.Preconditions;

import java.util.Objects;

/**
 * Abstract base class for implementations of {@link SourcePath}.
 */
abstract class AbstractSourcePath<T extends AbstractSourcePath<T>> implements SourcePath {

    /**
     * @return An opaque representation of the source path in a stable manner.
     */
    protected abstract Object asReference();

    protected abstract int compareReferences(T o);

    @SuppressWarnings("unchecked")
    @Override
    public int compareTo(SourcePath o) {
        if (o == this) {
            return 0;
        }

        int result = this.getClass().getName().compareTo(o.getClass().getName());
        if (result != 0) {
            return result;
        }

        Preconditions.checkState(this.getClass().equals(o.getClass()),
                "Classes are different but have the same name.");

        return this.compareReferences((T) o);
    }

    @Override
    public int hashCode() {
        return asReference().hashCode();
    }

    @Override
    public boolean equals(Object other) {
        if (other == null || !(other instanceof AbstractSourcePath)) {
            return false;
        }

        AbstractSourcePath<?> that = (AbstractSourcePath<?>) other;

        return Objects.equals(this.asReference(), that.asReference());
    }

    @Override
    public String toString() {
        return String.valueOf(asReference());
    }
}