added ChainLinks which allows us to access the resulting Chain structure

Author: Hakenadu

src/main/java/com/github/hakenadu/javalangchains/chains/Chain.java

@@ -1,7 +1,5 @@
 package com.github.hakenadu.javalangchains.chains;
 
-import org.apache.logging.log4j.LogManager;
-
 /**
  * Basic interface for all modular components in this repository. A
  * {@link Chain} accepts an input of type *I* and provides an output of type
@@ -31,12 +29,7 @@ public interface Chain<I, O> {
  * @return a new {@link Chain} consisting of the original {@link Chain} and the
  * passed one
  */
-default <B> Chain<I, B> chain(final Chain<O, B> next) {
-return input -> {
-final O prevOutput = run(input);
-LogManager.getLogger(next.getClass()).info("\n\n=================== INPUT ===================\n{}\n=============================================\n", prevOutput);
-
-return next.run(prevOutput);
-};
+default <B> ChainLink<I, O, B> chain(final Chain<O, B> next) {
+return new ChainLink<>(this, next);
 }
 }

src/main/java/com/github/hakenadu/javalangchains/chains/ChainLink.java

@@ -0,0 +1,60 @@
+package com.github.hakenadu.javalangchains.chains;
+
+/**
+ * A Link Between Worlds ;-)
+ *
+ * @param <I> type of the input chain's input
+ * @param <M> type of the input chain's output and the output chain's input
+ * @param <O> type of the output chain's output
+ */
+public final class ChainLink<I, M, O> implements Chain<I, O> {
+
+private final Chain<I, M> inputChain;
+private final Chain<M, O> outputChain;
+
+/**
+ * @param inputChain {@link #inputChain}
+ * @param outputChain {@link #outputChain}
+ */
+ChainLink(final Chain<I, M> inputChain, final Chain<M, O> outputChain) {
+this.inputChain = inputChain;
+this.outputChain = outputChain;
+}
+
+@Override
+public O run(final I input) {
+final M intermediateOutput = inputChain.run(input);
+
+final O output = outputChain.run(intermediateOutput);
+
+return output;
+}
+
+/**
+ * @return true if this {@link ChainLink} is the first one of the whole chain
+ */
+public boolean isHead() {
+return !(inputChain instanceof ChainLink);
+}
+
+/**
+ * @return true if this {@link ChainLink} is the final one of the whole chain
+ */
+public boolean isTail() {
+return !(outputChain instanceof ChainLink);
+}
+
+/**
+ * @return {@link #inputChain}
+ */
+public Chain<I, M> getInputChain() {
+return inputChain;
+}
+
+/**
+ * @return {@link #outputChain}
+ */
+public Chain<M, O> getOutputChain() {
+return outputChain;
+}
+}