com.couchbase.client.java.query.dsl.clause.UpdateForClause Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of java-client Show documentation
The official Couchbase Java SDK
There is a newer version: 3.7.7
/*
 * Copyright (C) 2016 Couchbase, Inc.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALING
 * IN THE SOFTWARE.
 */

package com.couchbase.client.java.query.dsl.clause;

import static com.couchbase.client.java.query.dsl.Expression.x;

import java.util.ArrayList;

import com.couchbase.client.java.query.dsl.Expression;

/**
 * UpdateForClause is a clause used in N1QL Updates, more specifically in the "set" part. For example:
 *
 * UPDATE bucket1 USE KEYS "abc123" SET "version.description" = "blabla" FOR variable IN path WHEN condition END;.
 *
 * This Clause allows you to produce an {@link Expression} that corresponds to "FOR variable IN path WHEN condition END".
 *
 * @author Simon Baslé
 * @since 2.2
 */
public class UpdateForClause {

    private ArrayList vars = new ArrayList();

    private UpdateForClause() { }

    /**
     * Creates an updateFor clause that starts with FOR variable IN path.
     * @param variable the first variable in the clause.
     * @param path the first path in the clause, an IN path.
     * @return the clause, for chaining. See {@link #when(Expression)} and {@link #end()} to complete the clause.
     */
    public static UpdateForClause forIn(String variable, String path) {
        UpdateForClause clause = new UpdateForClause();
        return clause.in(variable, path);
    }

    /**
     * Creates an updateFor clause that starts with FOR variable WITHIN path.
     *
     * @param variable the first variable in the clause.
     * @param path the first path in the clause, a WITHIN path.
     * @return the clause, for chaining. See {@link #when(Expression)} and {@link #end()} to complete the clause.
     */
    public static UpdateForClause forWithin(String variable, String path) {
        UpdateForClause clause = new UpdateForClause();
        return clause.within(variable, path);
    }

    /**
     * Adds a "variable IN path" section to the clause.
     *
     * @param variable the next variable to add to the clause.
     * @param path the path for the variable, an IN path.
     * @return the clause, for chaining. See {@link #when(Expression)} and {@link #end()} to complete the clause.
     */
    public UpdateForClause in(String variable, String path) {
        Expression in = x(variable + " IN " + path);
        vars.add(in);
        return this;
    }

    /**
     * Adds a "variable WITHIN path" section to the clause.
     *
     * @param variable the next variable to add to the clause.
     * @param path the path for the variable, a WITHIN path.
     * @return the clause, for chaining. See {@link #when(Expression)} and {@link #end()} to complete the clause.
     */
    public UpdateForClause within(String variable, String path) {
        vars.add(x(variable + " WITHIN " + path));
        return this;
    }

    /**
     * Terminates the clause by adding a condition to it ("WHEN condition END") and
     * returns the corresponding {@link Expression}.
     *
     * @param condition the condition to add to the clause, in a WHEN section.
     * @return the {@link Expression} representing the updateFor clause.
     * @see #end() if you don't need a condition.
     */
    public Expression when(Expression condition) {
        StringBuilder updateFor = new StringBuilder("FOR ");
        for (Expression var : vars) {
            updateFor.append(var.toString()).append(", ");
        }
        updateFor.delete(updateFor.length() - 2, updateFor.length());
        if (condition != null) {
            updateFor.append(" WHEN ").append(condition.toString());
        }
        updateFor.append(" END");
        return x(updateFor.toString());
    }

    /**
     * Terminates the clause without a particular WHEN condition ("END") and
     * returns the corresponding {@link Expression}.
     *
     * @return the {@link Expression} representing the updateFor clause.
     * @see #when(Expression) if you need a condition.
     */
    public Expression end() {
        return when(null);
    }
}