net.conquiris.schema.Schemas.java Source code

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Here is the source code for net.conquiris.schema.Schemas.java

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/*
 * Copyright (C) the original author or authors.
 *
 * 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 net.conquiris.schema;

import static com.google.common.base.Preconditions.checkNotNull;

import java.util.Arrays;

import com.google.common.collect.ImmutableBiMap;
import com.google.common.collect.ImmutableMap;

/**
 * Schema factory methods.
 * @author Andres Rodriguez
 */
public final class Schemas {
    /** Not instantiable. */
    private Schemas() {
        throw new AssertionError();
    }

    /** Empty schema. */
    private static final Schema EMPTY = new SchemaImpl(ImmutableBiMap.<String, SchemaItem>of());

    /** Returns the empty schema. */
    public static Schema empty() {
        return EMPTY;
    }

    /**
     * Creates a new schema.
     * @param items Schema items.
     * @return The created schema.
     * @throws NullPointerException if the argument or any of the items is {@code null}.
     * @throws IllegalArgumentException if there are duplicate items and/or item names.
     */
    public static Schema of(Iterable<? extends SchemaItem> items) {
        return EMPTY.override(items);
    }

    /**
     * Creates a new schema.
     * @param items Schema items.
     * @return The created schema.
     * @throws NullPointerException if the argument or any of the items is {@code null}.
     * @throws IllegalArgumentException if there are duplicate items and/or item names.
     */
    public static Schema of(SchemaItem... items) {
        return of(Arrays.asList(items));
    }

    /**
     * Creates a new schema with a single item.
     * @param item Schema item.
     * @return The created schema.
     * @throws NullPointerException if the argument is {@code null}.
     */
    public static Schema of(SchemaItem item) {
        checkNotNull(item, "The schema item must be provided");
        return new SchemaImpl(ImmutableMap.of(item.getName(), item));
    }

}