net.conquiris.qs.QueryToken.java Source code

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Here is the source code for net.conquiris.qs.QueryToken.java

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/*
 * Copyright 2008-2011 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.qs;

import static com.google.common.collect.Iterables.concat;
import static com.google.common.collect.Iterables.transform;
import static java.util.Arrays.asList;

import java.io.IOException;
import java.util.Arrays;

import com.google.common.base.Objects;
import com.google.common.collect.ImmutableList;

/**
 * Base class for query QS tokens.
 * @author Andres Rodriguez
 */
public abstract class QueryToken extends Token {
    /** Token arguments. */
    private final ImmutableList<Token> arguments;

    /**
     * Helper method to call the constructor.
     * @param t Token.
     * @return Constructor argument.
     */
    protected static Iterable<Token> tokens(Token t) {
        return ImmutableList.of(t);
    }

    /**
     * Helper method to call the constructor.
     * @param tokens Array of tokens.
     * @return Constructor argument.
     */
    protected static Iterable<Token> tokens(Token... tokens) {
        return asList(tokens);
    }

    /**
     * Helper method to call the constructor.
     * @param a Iterable of tokens.
     * @param b Array of tokens.
     * @return Constructor argument.
     */
    protected static Iterable<Token> tokens(Iterable<? extends Token> a, Token... b) {
        return concat(a, tokens(b));
    }

    /**
     * Helper method to call the constructor.
     * @param tokens Array of strings.
     * @return Constructor argument.
     */
    protected static Iterable<StringToken> strings(String... strings) {
        return transform(Arrays.asList(strings), StringToken.STRING2TOKEN);
    }

    /**
     * Constructor.
     * @param arguments Query arguments.
     * @throws NullPointerException if any of the arguments is null.
     */
    protected QueryToken(Iterable<? extends Token> arguments) {
        this.arguments = ImmutableList.copyOf(arguments);
    }

    /** Returns the query arguments. */
    public ImmutableList<Token> getArguments() {
        return arguments;
    }

    /**
     * Returns an argument with a specific token type.
     * @param i Argument index.
     * @param type Argument type.
     * @return The requested argument.
     * @throws IndexOutOfBoundsException if the index is incorrect.
     */
    public <T extends Token> T getArgument(int i, Class<T> type) {
        return type.cast(arguments.get(i));
    }

    @Override
    void write(QS qs, Appendable a) throws IOException {
        a.append('(');
        a.append(qs.getQueryKey(this));
        a.append(' ');
        for (Token t : arguments) {
            t.write(false, qs, a);
        }
        a.append(')');
    }

    @Override
    public int hashCode() {
        return Objects.hashCode(getClass(), arguments);
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj) {
            return true;
        }
        if (obj == null || getClass() != obj.getClass()) {
            return false;
        }
        return arguments.equals(((QueryToken) obj).arguments);
    }

}