diff --git a/src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/network/response/ErrorResponse.java b/src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/network/response/ErrorResponse.java new file mode 100644 index 0000000..602181b --- /dev/null +++ b/src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/network/response/ErrorResponse.java @@ -0,0 +1,34 @@ +package ch.unibas.dmi.dbis.cs108.casono.server.network.response; + +import ch.unibas.dmi.dbis.cs108.casono.server.network.sessions.SessionId; + +/** Response representing an error outcome for a client's request. */ +public class ErrorResponse extends Response { + /** + * Construct an error response with a code and message. + * + * @param sessionId the target session id + * @param requestId the originating request id + * @param errorCode a short error code identifying the failure + * @param errorMessage a human readable error message + */ + public ErrorResponse( + SessionId sessionId, int requestId, String errorCode, String errorMessage) { + super( + sessionId, + requestId, + ResponseBody.builder().param("CODE", errorCode).param("MSG", errorMessage).build()); + } + + /** + * {@inheritDoc} + * + *

This implementation returns the fixed {@code -ERR} prefix. + * + * @return the {@code -ERR} prefix + */ + @Override + public String prefix() { + return "-ERR"; + } +} diff --git a/src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/network/response/OkResponse.java b/src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/network/response/OkResponse.java new file mode 100644 index 0000000..a3f26c5 --- /dev/null +++ b/src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/network/response/OkResponse.java @@ -0,0 +1,20 @@ +package ch.unibas.dmi.dbis.cs108.casono.server.network.response; + +import ch.unibas.dmi.dbis.cs108.casono.server.network.sessions.SessionId; + +/** + * A simple success response with an empty body. + * + *

Use this to acknowledge successful requests that do not carry additional payload data. + */ +public class OkResponse extends SuccessResponse { + /** + * Create a minimal successful response (no body content). + * + * @param sessionId the target session id + * @param requestId the originating request id + */ + public OkResponse(SessionId sessionId, int requestId) { + super(sessionId, requestId, ResponseBody.builder().build()); + } +} diff --git a/src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/network/response/PrimitiveResponse.java b/src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/network/response/PrimitiveResponse.java index 38a7422..1ef7a6a 100644 --- a/src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/network/response/PrimitiveResponse.java +++ b/src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/network/response/PrimitiveResponse.java @@ -2,4 +2,11 @@ package ch.unibas.dmi.dbis.cs108.casono.server.network.response; import ch.unibas.dmi.dbis.cs108.casono.server.network.sessions.SessionId; +/** + * Immutable transport record representing an encoded response ready for delivery to a session. + * + * @param sessionId the target session id + * @param requestId the originating request id + * @param payload the serialized response payload + */ public record PrimitiveResponse(SessionId sessionId, int requestId, String payload) {} diff --git a/src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/network/response/Response.java b/src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/network/response/Response.java new file mode 100644 index 0000000..8a3cf96 --- /dev/null +++ b/src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/network/response/Response.java @@ -0,0 +1,58 @@ +package ch.unibas.dmi.dbis.cs108.casono.server.network.response; + +import ch.unibas.dmi.dbis.cs108.casono.server.network.sessions.SessionId; + +/** Abstract base class for all server responses sent to clients. */ +public abstract class Response { + private final SessionId sessionId; + private final int requestId; + private final ResponseBody body; + + /** + * Create a new {@code Response}. + * + * @param sessionId the id of the session this response targets + * @param requestId the request identifier this response corresponds to + * @param body the structured response body + */ + protected Response(SessionId sessionId, int requestId, ResponseBody body) { + this.sessionId = sessionId; + this.requestId = requestId; + this.body = body; + } + + /** + * Returns the protocol prefix for this response (for example {@code "+OK"} or {@code "-ERR"}). + * + * @return the response prefix string used by the encoder + */ + public abstract String prefix(); + + /** + * Returns the session id that should receive this response. + * + * @return the target {@link SessionId} + */ + public SessionId getSessionId() { + return sessionId; + } + + /** + * Returns the request identifier associated with this response. + * + * @return the numeric request id + */ + public int getRequestId() { + return requestId; + } + + /** + * Returns the immutable {@link ResponseBody} that carries the structured payload for this + * response. + * + * @return the response body + */ + public ResponseBody getBody() { + return body; + } +} diff --git a/src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/network/response/ResponseBlock.java b/src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/network/response/ResponseBlock.java new file mode 100644 index 0000000..075abaf --- /dev/null +++ b/src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/network/response/ResponseBlock.java @@ -0,0 +1,12 @@ +package ch.unibas.dmi.dbis.cs108.casono.server.network.response; + +import java.util.List; + +/** + * A block node that contains a tag and a list of child {@link ResponseNode} elements. Blocks can be + * nested to build hierarchical response bodies. + * + * @param tag the block tag + * @param children the child nodes contained in this block + */ +public record ResponseBlock(String tag, List children) implements ResponseNode {} diff --git a/src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/network/response/ResponseBody.java b/src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/network/response/ResponseBody.java new file mode 100644 index 0000000..8c52ffc --- /dev/null +++ b/src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/network/response/ResponseBody.java @@ -0,0 +1,40 @@ +package ch.unibas.dmi.dbis.cs108.casono.server.network.response; + +import java.util.List; + +/** + * Immutable container for the structured content of a {@link Response}. + * + *

A {@code ResponseBody} holds an ordered list of {@link ResponseNode} items (parameters and + * blocks). Use {@link #builder()} to construct instances. + */ +public class ResponseBody { + private final List nodes; + + /** + * Package-private constructor used by {@link ResponseBodyBuilder}. + * + * @param nodes the list of response nodes to include in this body + */ + ResponseBody(List nodes) { + this.nodes = List.copyOf(nodes); + } + + /** + * Create a new {@link ResponseBodyBuilder} for assembling a response body. + * + * @return a fresh builder instance + */ + public static ResponseBodyBuilder builder() { + return new ResponseBodyBuilder(); + } + + /** + * Returns the ordered list of {@link ResponseNode} elements contained in this body. + * + * @return an immutable list of nodes + */ + public List nodes() { + return nodes; + } +} diff --git a/src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/network/response/ResponseBodyBuilder.java b/src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/network/response/ResponseBodyBuilder.java new file mode 100644 index 0000000..f6491b0 --- /dev/null +++ b/src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/network/response/ResponseBodyBuilder.java @@ -0,0 +1,51 @@ +package ch.unibas.dmi.dbis.cs108.casono.server.network.response; + +import java.util.ArrayList; +import java.util.List; +import java.util.function.Consumer; + +/** + * Builder for {@link ResponseBody} instances. + * + *

Provides methods to append parameter nodes and nested blocks and to produce an immutable + * {@link ResponseBody} via {@link #build()}. + */ +public class ResponseBodyBuilder { + private final List nodes = new ArrayList<>(); + + /** + * Add a key/value parameter to the response body under construction. + * + * @param key the parameter name + * @param value the parameter value (will be converted to string when encoded) + * @return this builder for fluent chaining + */ + public ResponseBodyBuilder param(String key, Object value) { + nodes.add(new ResponseParameter(key, value)); + return this; + } + + /** + * Add a nested block with the given tag. The provided consumer receives a child builder to + * populate the block content. + * + * @param tag the block tag + * @param content consumer that appends child nodes to the block + * @return this builder for fluent chaining + */ + public ResponseBodyBuilder block(String tag, Consumer content) { + ResponseBodyBuilder childBuilder = new ResponseBodyBuilder(); + content.accept(childBuilder); + nodes.add(new ResponseBlock(tag, childBuilder.build().nodes())); + return this; + } + + /** + * Build an immutable {@link ResponseBody} from the accumulated nodes. + * + * @return a new {@link ResponseBody} + */ + public ResponseBody build() { + return new ResponseBody(nodes); + } +} diff --git a/src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/network/response/ResponseDispatcher.java b/src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/network/response/ResponseDispatcher.java new file mode 100644 index 0000000..57b9181 --- /dev/null +++ b/src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/network/response/ResponseDispatcher.java @@ -0,0 +1,36 @@ +package ch.unibas.dmi.dbis.cs108.casono.server.network.response; + +import ch.unibas.dmi.dbis.cs108.casono.server.network.sessions.Session; +import ch.unibas.dmi.dbis.cs108.casono.server.network.sessions.SessionManager; + +/** + * Helper that dispatches {@link Response} instances to the corresponding {@link Session} by + * encoding them and enqueuing the resulting {@link PrimitiveResponse} into the session's response + * queue. + */ +public class ResponseDispatcher { + private final SessionManager sessionManager; + + /** + * Create a dispatcher bound to a {@link SessionManager}. + * + * @param sessionManager manager used to resolve sessions + */ + public ResponseDispatcher(SessionManager sessionManager) { + this.sessionManager = sessionManager; + } + + /** + * Encode the given {@link Response} and enqueue the resulting {@link PrimitiveResponse} into + * the target session's response queue. + * + * @param response the response to dispatch + * @throws InterruptedException if the thread is interrupted while waiting to enqueue the + * primitive response + */ + public void dispatch(Response response) throws InterruptedException { + PrimitiveResponse primitiveResponse = ResponseEncoder.encode(response); + Session session = sessionManager.getSessionById(response.getSessionId()); + session.getResponseQueue().put(primitiveResponse); + } +} diff --git a/src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/network/response/ResponseEncoder.java b/src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/network/response/ResponseEncoder.java new file mode 100644 index 0000000..dbe8d12 --- /dev/null +++ b/src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/network/response/ResponseEncoder.java @@ -0,0 +1,98 @@ +package ch.unibas.dmi.dbis.cs108.casono.server.network.response; + +/** + * Utility responsible for encoding a {@link Response} into a protocol payload string and wrapping + * it into a {@link PrimitiveResponse} suitable for transmission. + */ +public class ResponseEncoder { + private static final String INDENT = "\t"; + private static final String NEWLINE = "\n"; + + /** + * Encode a {@link Response} into a {@link PrimitiveResponse} containing the serialized payload + * string. + * + * @param response the response to encode + * @return a {@link PrimitiveResponse} with encoded payload + */ + public static PrimitiveResponse encode(Response response) { + StringBuilder sb = new StringBuilder(); + sb.append(response.prefix()); + + for (ResponseNode node : response.getBody().nodes()) { + sb.append(NEWLINE); + encodeNode(node, sb, 1); + } + + sb.append(NEWLINE).append("END"); + + return new PrimitiveResponse( + response.getSessionId(), response.getRequestId(), sb.toString()); + } + + /** + * Internal helper to encode any {@link ResponseNode}. + * + * @param node node to encode + * @param sb string builder to append to + * @param depth current indentation depth + */ + private static void encodeNode(ResponseNode node, StringBuilder sb, int depth) { + if (node instanceof ResponseParameter param) { + encodeParameter(param, sb, depth); + } else if (node instanceof ResponseBlock block) { + encodeBlock(block, sb, depth); + } + } + + /** + * Encode a {@link ResponseParameter} into the string builder. + * + * @param param the parameter to encode + * @param sb the output builder + * @param depth indentation depth + */ + private static void encodeParameter(ResponseParameter param, StringBuilder sb, int depth) { + sb.append(INDENT.repeat(depth)); + sb.append(param.key()); + sb.append("="); + sb.append(maskIfNeeded(param.value().toString())); + } + + /** + * Encode a {@link ResponseBlock}, including its children and terminating with an {@code END} + * marker. + * + * @param block the block to encode + * @param sb the output builder + * @param depth current indentation depth + */ + private static void encodeBlock(ResponseBlock block, StringBuilder sb, int depth) { + sb.append(INDENT.repeat(depth)); + sb.append(block.tag()); + + for (ResponseNode child : block.children()) { + sb.append(NEWLINE); + encodeNode(child, sb, depth + 1); + } + + sb.append(NEWLINE); + sb.append(INDENT.repeat(depth)); + sb.append("END"); + } + + /** + * Quote or escape the provided value if it contains whitespace or single quotes so the encoded + * payload remains parseable. + * + * @param value the raw string value + * @return quoted/escaped value + */ + private static String maskIfNeeded(String value) { + if (value.contains(" ") || value.contains("'")) { + String escaped = value.replace("'", "\\'"); + return "'" + escaped + "'"; + } + return value; + } +} diff --git a/src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/network/response/ResponseNode.java b/src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/network/response/ResponseNode.java new file mode 100644 index 0000000..c3af815 --- /dev/null +++ b/src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/network/response/ResponseNode.java @@ -0,0 +1,8 @@ +package ch.unibas.dmi.dbis.cs108.casono.server.network.response; + +/** + * Marker interface for elements that may appear in a {@link ResponseBody}. + * + *

Implementations include {@link ResponseParameter} and {@link ResponseBlock}. + */ +public interface ResponseNode {} diff --git a/src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/network/response/ResponseParameter.java b/src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/network/response/ResponseParameter.java new file mode 100644 index 0000000..87f599a --- /dev/null +++ b/src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/network/response/ResponseParameter.java @@ -0,0 +1,23 @@ +package ch.unibas.dmi.dbis.cs108.casono.server.network.response; + +/** + * A parameter node stored in a {@link ResponseBody}. + * + *

Represents a simple key/value pair. Callers can use {@link #rawValue()} to obtain the string + * representation of the stored value. + * + * @param key the parameter name + * @param value the parameter value + */ +public record ResponseParameter(String key, Object value) implements ResponseNode { + /** + * Returns the raw string representation of the stored value. This is a convenience wrapper + * around {@code Object#toString()} and may throw {@link NullPointerException} if the stored + * value is {@code null}. + * + * @return the value as string + */ + public String rawValue() { + return value.toString(); + } +} diff --git a/src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/network/response/SuccessResponse.java b/src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/network/response/SuccessResponse.java new file mode 100644 index 0000000..e88913f --- /dev/null +++ b/src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/network/response/SuccessResponse.java @@ -0,0 +1,34 @@ +package ch.unibas.dmi.dbis.cs108.casono.server.network.response; + +import ch.unibas.dmi.dbis.cs108.casono.server.network.sessions.SessionId; + +/** + * Abstract {@link Response} specialization indicating a successful outcome. + * + *

Implementations of this class use the {@code +OK} prefix. It provides a protected constructor + * so subclasses can supply the response body content. + */ +public abstract class SuccessResponse extends Response { + /** + * Create a successful response with the provided body. + * + * @param sessionId the session id this response targets + * @param requestId the originating request id + * @param body the response body + */ + protected SuccessResponse(SessionId sessionId, int requestId, ResponseBody body) { + super(sessionId, requestId, body); + } + + /** + * {@inheritDoc} + * + *

This implementation returns the fixed {@code +OK} prefix. + * + * @return the {@code +OK} prefix + */ + @Override + public final String prefix() { + return "+OK"; + } +}