Merge branch 'master' of https://github.com/manwar/perlweeklychallenge-club

1 files changed, 74 insertions, 0 deletions

diff --git a/challenge-255/luca-ferrari/pljava/src/main/java/Task1.java b/challenge-255/luca-ferrari/pljava/src/main/java/Task1.java
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+++ b/challenge-255/luca-ferrari/pljava/src/main/java/Task1.java
@@ -0,0 +1,74 @@
+package PWC255;
+
+/**
+ * PL/Java implementation for PWC 255
+ * Task 1
+ * See <https://perlweeklychallenge.org/blog/perl-weekly-challenge-255>
+ *
+ *
+ * To compile on the local machine:
+
+ $ export JAVA_HOME=/usr/lib/jvm/java-17-openjdk-amd64/  # if not already set
+ $ mvn clean build
+ $ $ scp target/PWC253-1.jar  luca@venkman:/tmp
+
+
+ * To install into PostgreSQL execute:
+
+ select sqlj.install_jar( 'file:///tmp/PWC255-1.jar', 'PWC255', true );
+ select sqlj.set_classpath( 'public', 'PWC255' );
+
+ select task1_pljava();
+
+ and then to redeploy:
+
+ select sqlj.replace_jar( 'file:///tmp/PWC255-1.jar', 'PWC255', true );
+
+*/
+
+import org.postgresql.pljava.*;
+import org.postgresql.pljava.annotation.Function;
+import static org.postgresql.pljava.annotation.Function.Effects.IMMUTABLE;
+import static org.postgresql.pljava.annotation.Function.OnNullInput.RETURNS_NULL;
+
+import java.util.*;
+import java.sql.SQLException;
+import java.util.logging.*;
+
+public class Task1 {
+
+    private final static Logger logger = Logger.getAnonymousLogger();
+
+    @Function( onNullInput = RETURNS_NULL, effects = IMMUTABLE )
+    public static final String task1_pljava( String origin, String shuffled ) throws SQLException {
+	logger.log( Level.INFO, "Entering task1_pljava" );
+
+	if ( origin.length() + 1 != shuffled.length() ) {
+	    throw new SQLException( "Shuffled string should be one character longer than the original one" );
+	}
+
+	Map<String, Integer> classification = new HashMap<String, Integer>();
+	for ( String needle : shuffled.split( "" ) ) {
+	    int value = classification.keySet().contains( needle )
+		? classification.get( needle )
+		: 0;
+
+	    classification.put( needle, ++value );
+	}
+
+
+	for ( String comparison : origin.split( "" ) ) {
+	    int value = classification.get( comparison );
+	    value--;
+
+	    if ( value > 0 )
+		classification.put( comparison, value );
+	    else
+		classification.remove( comparison );
+	}
+
+
+	return classification.keySet().iterator().next();
+
+    }
+}