PrimaryKey.java

/*
 * Copyright 2014-2017 Amazon.com, Inc. or its affiliates. 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.
 * A copy of the License is located at
 *
 *  http://aws.amazon.com/apache2.0
 *
 * or in the "license" file accompanying this file. This file 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.amazonaws.services.dynamodbv2.document;

import java.util.Collection;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.Set;

import com.amazonaws.services.dynamodbv2.document.internal.InternalUtils;

/**
 * Used to represent a primary key that has one or multiple key components.
 */
public class PrimaryKey {
    private final Map<String, KeyAttribute> components = new LinkedHashMap<String, KeyAttribute>();

    public PrimaryKey() {}

    /**
     * Constructs with the specified key components.
     */
    public PrimaryKey(KeyAttribute ...components) {
        addComponents(components);
    }

    /**
     * Constructs with a hash key.
     */
    public PrimaryKey(String hashKeyName, Object hashKeyValue) {
        addComponent(hashKeyName, hashKeyValue);
    }

    /**
     * Constructs with a hash key and a range key.
     */
    public PrimaryKey(String hashKeyName, Object hashKeyValue,
            String rangeKeyName, Object rangeKeyValue) {
        if (hashKeyName.equals(rangeKeyName))
            throw new IllegalArgumentException("hashKyeName must not be the same as the rangeKeyName");
        addComponent(hashKeyName, hashKeyValue);
        addComponent(rangeKeyName, rangeKeyValue);
    }

    /**
     * Returns all the key components of this primary key.
     */
    public Collection<KeyAttribute> getComponents() {
        return components.values();
    }

    /**
     * Returns all the key component names of this primary key as a set.
     */
    public Set<String> getComponentNameSet() {
        return components.keySet();
    }

    /**
     * Returns true if this primary has the specified key attribute name;
     * false otherwise.
     */
    public boolean hasComponent(String attrName) {
        return components.containsKey(attrName);
    }

    /**
     * Add one or multiple key components to this primary key.
     *
     * Note adding a key component with the same name as that of an existing
     * one would overwrite and become a single key component instead of two.
     */
    public PrimaryKey addComponents(KeyAttribute ... components) {
        if (components != null) {
            for (KeyAttribute ka: components) {
                InternalUtils.rejectNullInput(ka);
                this.components.put(ka.getName(), ka);
            }
        }
        return this;
    }

    /**
     * Add a key component to this primary key.
     *
     * Note adding a key component with the same name as that of an existing
     * one would overwrite and become a single key component instead of two.
     */
    public PrimaryKey addComponent(String keyAttributeName, Object keyAttributeValue) {
        components.put(keyAttributeName,
            new KeyAttribute(keyAttributeName, keyAttributeValue));
        return this;
    }

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

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

    @Override
    public boolean equals(Object in) {
        if (in instanceof PrimaryKey) {
            PrimaryKey that = (PrimaryKey)in;
            return this.components.equals(that.components);
        } else {
            return false;
        }
    }
}