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package org.graalvm.polyglot.tck;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.List;
import java.util.Objects;
import java.util.stream.Collectors;
import org.graalvm.polyglot.Value;

The unit of execution with assigned parameters and result types. The Snippet represents an execution of value constructor, statement, expression and script. The Snippet provides parameter(s) and return types used to compose the Snippets. 
Since:
0.30/**
 * The unit of execution with assigned parameters and result types. The {@link Snippet} represents
 * an execution of value constructor, statement, expression and script. The {@link Snippet} provides
 * parameter(s) and return types used to compose the {@link Snippet}s.
 *
 * @since 0.30
 */
public final class Snippet {
    private final String id;
    private final Value executableValue;
    private final TypeDescriptor type;
    private final List<? extends TypeDescriptor> parameterTypes;
    private final ResultVerifier verifier;

    private Snippet(
                    final String id,
                    final Value executableValue,
                    final TypeDescriptor type,
                    final List<? extends TypeDescriptor> parameterTypes,
                    final ResultVerifier verifier) {
        if (!executableValue.canExecute()) {
            throw new IllegalArgumentException("The executableValue has to be executable.");
        }
        this.id = id;
        this.executableValue = executableValue;
        this.type = type;
        this.parameterTypes = parameterTypes;
        this.verifier = verifier;
    }

    
Returns the identifier of a snippet. The Snippets from a single LanguageProvider with the same identifier but different types are treated as overloads. 
Returns:
the Snippet identifier
Since:
0.30/**
     * Returns the identifier of a snippet. The {@link Snippet}s from a single
     * {@link LanguageProvider} with the same identifier but different types are treated as
     * overloads.
     *
     * @return the {@link Snippet} identifier
     * @since 0.30
     */
    public String getId() {
        return id;
    }

    
Returns the function executing the Snippet. 
Returns:
the executable Value
Since:
0.30/**
     * Returns the function executing the {@link Snippet}.
     *
     * @return the executable {@link Value}
     * @since 0.30
     */
    public Value getExecutableValue() {
        return executableValue;
    }

    
Returns the Snippet return type. 
Returns:
the return type
Since:
0.30/**
     * Returns the {@link Snippet} return type.
     *
     * @return the return type
     * @since 0.30
     */
    public TypeDescriptor getReturnType() {
        return type;
    }

    
Returns the types of Snippet formal parameters. 
Returns:
the parameter types
Since:
0.30/**
     * Returns the types of {@link Snippet} formal parameters.
     *
     * @return the parameter types
     * @since 0.30
     */
    public List<? extends TypeDescriptor> getParameterTypes() {
        return parameterTypes;
    }

    
Returns the ResultVerifier to verify the execution result. 
See Also:
ResultVerifier#accept(org.graalvm.polyglot.tck.ResultVerifier.SnippetRun).
Returns:
either a custom or the default ResultVerifier.
Since:
0.30/**
     * Returns the {@link ResultVerifier} to verify the execution result.
     *
     * @return either a custom or the default {@link ResultVerifier}.
     * @see ResultVerifier#accept(org.graalvm.polyglot.tck.ResultVerifier.SnippetRun).
     * @since 0.30
     */
    public ResultVerifier getResultVerifier() {
        return verifier;
    }

    
{@inheritDoc}
Since:
0.30/**
     * {@inheritDoc}
     *
     * @since 0.30
     */
    @Override
    public String toString() {
        return new StringBuilder(id).append(parameterTypes.stream().map(Object::toString).collect(Collectors.joining(", ", "(", ")"))).append(':').append(type).toString();
    }

    
Creates a new Snippet builder object. 
Params:
id – the Snippet identifier The Snippets from a single LanguageProvider with the same identifier but different types are treated as overloads.
executableValue – the executable Value used to execute the Snippet
executableReturnType – the Snippet return type
Returns:
the new Builder
Since:
0.30/**
     * Creates a new {@link Snippet} builder object.
     *
     * @param id the {@link Snippet} identifier The {@link Snippet}s from a single
     *            {@link LanguageProvider} with the same identifier but different types are treated
     *            as overloads.
     * @param executableValue the executable {@link Value} used to execute the {@link Snippet}
     * @param executableReturnType the {@link Snippet} return type
     * @return the new {@link Builder}
     * @since 0.30
     */
    public static Builder newBuilder(
                    final String id,
                    final Value executableValue,
                    final TypeDescriptor executableReturnType) {
        return new Builder(id, executableValue, executableReturnType);
    }

    
The builder of a Snippet. 
Since:
0.30/**
     * The builder of a {@link Snippet}.
     *
     * @since 0.30
     */
    public static final class Builder {
        private final String id;
        private final Value executableValue;
        private TypeDescriptor executableReturnType;
        private List<TypeDescriptor> parameterTypes;
        private ResultVerifier verifier;

        private Builder(
                        final String id,
                        final Value executableValue,
                        final TypeDescriptor executableReturnType) {
            Objects.requireNonNull(id);
            Objects.requireNonNull(executableValue);
            Objects.requireNonNull(executableReturnType);
            this.id = id;
            this.executableValue = executableValue;
            this.executableReturnType = executableReturnType;
            this.parameterTypes = new ArrayList<>();
        }

        
Sets the Snippet formal parameter types. 
Params:
parameterTypes – the types of Snippet's parameters
Returns:
this Builder
Since:
0.30/**
         * Sets the {@link Snippet} formal parameter types.
         *
         * @param parameterTypes the types of {@link Snippet}'s parameters
         * @return this {@link Builder}
         * @since 0.30
         */
        public Builder parameterTypes(@SuppressWarnings("hiding") final TypeDescriptor... parameterTypes) {
            Objects.requireNonNull(parameterTypes);
            this.parameterTypes = Arrays.asList(parameterTypes);
            return this;
        }

        
Sets a custom verifier of a result of the Snippet execution. 
Params:
resultVerifier – the custom ResultVerifier
See Also:
ResultVerifier#accept(org.graalvm.polyglot.tck.ResultVerifier.SnippetRun).
Returns:
this Builder
Since:
0.30/**
         * Sets a custom verifier of a result of the {@link Snippet} execution.
         *
         * @param resultVerifier the custom {@link ResultVerifier}
         * @return this {@link Builder}
         * @see ResultVerifier#accept(org.graalvm.polyglot.tck.ResultVerifier.SnippetRun).
         * @since 0.30
         */
        public Builder resultVerifier(final ResultVerifier resultVerifier) {
            this.verifier = resultVerifier;
            return this;
        }

        
Creates a new Snippet configured by this Builder. 
Returns:
the Snippet
Since:
0.30/**
         * Creates a new {@link Snippet} configured by this {@link Builder}.
         *
         * @return the {@link Snippet}
         * @since 0.30
         */
        public Snippet build() {
            return new Snippet(
                            id,
                            executableValue,
                            executableReturnType,
                            Collections.unmodifiableList(parameterTypes),
                            verifier != null ? verifier : ResultVerifier.getDefaultResultVerifier());
        }
    }
}