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--- documents:120206pyip_cooking:python_imagej_cookbook [2022/10/07 19:50] – [Plugin: MorphoLibJ] kota
+++ documents:120206pyip_cooking:python_imagej_cookbook [2022/10/16 06:37] – [Using Java8 Stream] kota
@@ Line 787: / Line 787: @@
 zip command creates a list of tuples from elements of arrays a and b.
+==== Using Java8 Stream ====
+Stream-related syntax introduced from Java8 is useful for writing clear codes, but cannot be directly used in Jython. Below is a way to use StreamAPI, by introducing Jython classes implementing the Consumer interface. I took this idea from [[https://stackoverflow.com/questions/45417732/jython-function-to-java-consumer|here]].
+<code python>
+from java.util.Arrays import asList
+from java.util.function import Predicate, Consumer, Function
+from java.util.stream import Collectors
+from java.util import Arrays
+class jc(Consumer):
+    def __init__(self, fn):
+        self.accept=fn
+class jf(Function):
+    def __init__(self, fn):
+        self.apply = fn
+class jp(Predicate):
+    def __init__(self, fn):
+        self.test = fn
+def jprint(x):
+	print x
+tt = ["a", "b", "c"]
+c = Arrays.stream(tt).count()
+print c
+print "forEach printing"
+Arrays.stream(tt).forEach(jc(lambda x: jprint("="+x)))
+print "forEach printing parallelly"
+Arrays.stream(tt).parallel().forEach(jc(lambda x: jprint("="+x)))
+print "has b?", Arrays.stream(tt).anyMatch(jp(lambda x: x=="b"))
+print "has z?", Arrays.stream(tt).anyMatch(jp(lambda x: x=="z"))
+# convert to Java List<>
+jtt = Arrays.asList(tt)
+jtt.stream().forEach(jc(lambda x: jprint("+"+x)))
+</code>
 ===== Event Listener =====