From 03c89341225a7318e30e70ecfa3379c602b987a0 Mon Sep 17 00:00:00 2001
From: wolray <290061869@qq.com>
Date: Wed, 15 Mar 2023 16:49:28 +0800
Subject: [PATCH] [add] direct Stream support as output

---
 .../com/alibaba/excel/EasyExcelFactory.java   | 19 ++++++++++
 .../java/com/alibaba/excel/StreamBuilder.java | 36 +++++++++++++++++++
 2 files changed, 55 insertions(+)
 create mode 100644 easyexcel-core/src/main/java/com/alibaba/excel/StreamBuilder.java

diff --git a/easyexcel-core/src/main/java/com/alibaba/excel/EasyExcelFactory.java b/easyexcel-core/src/main/java/com/alibaba/excel/EasyExcelFactory.java
index 80c40851..6d85d296 100644
--- a/easyexcel-core/src/main/java/com/alibaba/excel/EasyExcelFactory.java
+++ b/easyexcel-core/src/main/java/com/alibaba/excel/EasyExcelFactory.java
@@ -3,7 +3,10 @@ package com.alibaba.excel;
 import java.io.File;
 import java.io.InputStream;
 import java.io.OutputStream;
+import java.util.function.Consumer;
+import java.util.stream.Stream;
 
+import com.alibaba.excel.context.AnalysisContext;
 import com.alibaba.excel.read.builder.ExcelReaderBuilder;
 import com.alibaba.excel.read.builder.ExcelReaderSheetBuilder;
 import com.alibaba.excel.read.listener.ReadListener;
@@ -246,6 +249,22 @@ public class EasyExcelFactory {
         return read(pathName, null, readListener);
     }
 
+    public static <T> Stream<T> read(String pathName, Class<T> head) {
+        Consumer<Consumer<T>> sequence = c -> {
+            ReadListener<T> listener = new ReadListener<>() {
+                @Override
+                public void invoke(T data, AnalysisContext context) {
+                    c.accept(data);
+                }
+
+                @Override
+                public void doAfterAllAnalysed(AnalysisContext context) {}
+            };
+            read(pathName, head, listener).sheet().doRead();
+        };
+        return StreamBuilder.stream(sequence);
+    }
+
     /**
      * Build excel the read
      *
diff --git a/easyexcel-core/src/main/java/com/alibaba/excel/StreamBuilder.java b/easyexcel-core/src/main/java/com/alibaba/excel/StreamBuilder.java
new file mode 100644
index 00000000..486edec4
--- /dev/null
+++ b/easyexcel-core/src/main/java/com/alibaba/excel/StreamBuilder.java
@@ -0,0 +1,36 @@
+package com.alibaba.excel;
+
+import java.util.Iterator;
+import java.util.NoSuchElementException;
+import java.util.Spliterator;
+import java.util.Spliterators;
+import java.util.function.Consumer;
+import java.util.stream.Stream;
+import java.util.stream.StreamSupport;
+
+/**
+ * build stream from generator
+ */
+public class StreamBuilder {
+    public static <T> Stream<T> stream(Consumer<Consumer<T>> sequence) {
+        Iterator<T> iterator = new Iterator<>() {
+            @Override
+            public boolean hasNext() {
+                throw new NoSuchElementException();
+            }
+
+            @Override
+            public T next() {
+                throw new NoSuchElementException();
+            }
+
+            @Override
+            public void forEachRemaining(Consumer<? super T> action) {
+                sequence.accept(action::accept);
+            }
+        };
+        return StreamSupport.stream(
+            Spliterators.spliteratorUnknownSize(iterator, Spliterator.ORDERED),
+            false);
+    }
+}